ELECTROCATALYST COMPOSITION FOR WATER SPLITTING AND A PROCESS FOR ITS PREPARATION

Abstract

ABSTRACT ELECTROCATALYST COMPOSITION FOR WATER SPLITTING AND A PROCESS FOR ITS PREPARATION The present disclosure relates to electrocatalyst composition for water splitting. The electrocatalyst composition for water splitting is prepared with a polymer substrate containing metal composite microparticles. The metal composite microparticles are incorporated in a natural material eggshell microparticles. The electrocatalyst composition provides enhanced electrochemical performance, OER, and HER performance, and requires a low amount of energy. Figure 1

Specification

Description:FIELD
The present disclosure relates to electrocatalyst composition. Particularly, it relates to the electrocatalyst composition for water splitting and a process for its preparation. More particularly, the present disclosure relates to the electrocatalyst composition for the synthesis of hydrogen.
DEFINITIONS
As used in the present disclosure, the following terms are generally intended to have the meaning as set forth below, except to the extent that the context in which they are used indicates otherwise.
Electrocatalyst - The term 'electrocatalyst' refers to a material that increases the rate of an electrochemical reaction. The electrocatalyst works by lowering the activation energy of the reaction, which is the energy required to get the reaction started.
Oxygen evolution reaction (OER) - The term 'oxygen evolution reaction' refers to an electrochemical process that involves the splitting of water molecules (H2O) into oxygen gas (O2) and protons (H+).
Hydrogen evolution reaction (HER) - The term 'hydrogen evolution reaction' refers to an electrochemical process that involves the generation of hydrogen gas (H₂) from protons (H⁺).
BACKGROUND
The background information herein below relates to the present disclosure but is not necessarily prior art.
Water splitting is a process of splitting water (H2O) into hydrogen (H2) and oxygen (O2), offering a promising path towards clean and sustainable energy production. The process of water splitting is slow and consumes a high amount of energy, hence it is not feasible in the industry for the implementation of clean energy. The speed of the process can be enhanced by using electrocatalysts, which enable water splitting to occur more efficiently, consuming less electrical energy and maximizing hydrogen production.
Conventional electrocatalysts are prepared using transition metals and their compounds such as nickel, iron, cobalt, platinum, and their oxides or phosphides; perovskites; and carbon-based catalysts. These electrocatalysts for water splitting are associated with several challenges. Precious metal-based catalysts like platinum make large-scale implementation financially unfeasible increasing the cost of catalysts. Additionally, some catalysts degrade over time, requiring frequent replacements and raising environmental concerns. Moreover, while some catalysts excel at one reaction (HER or OER), they often struggle with the other, necessitating complex and expensive setups with multiple catalysts. Furthermore, the existing catalysts require significant energy input, leading to efficiency losses, and complexity in manufacturing. These drawbacks highlight the crucial need for developing cost-effective, durable, and efficient catalysts that minimize environmental impact and pave the way for the widespread adoption of water splitting as a clean energy source.
Therefore, there is a need to provide an electrocatalyst composition for the water splitting that mitigates the aforementioned drawbacks or at least provides a useful alternative.
OBJECTS
Some of the objects of the present disclosure, which at least one embodiment herein satisfies, are as follows.
It is an object of the present disclosure to ameliorate one or more problems of the background or to at least provide a useful alternative.
An object of the present disclosure is to provide an electrocatalyst composition.
It is an object of the present disclosure to provide an electrocatalyst composition for water splitting.
An object of the present disclosure is to provide an electrocatalyst composition that effectively catalyzes HER and OER.
Yet another object of the present disclosure is to provide an electrocatalyst composition prepared by using sustainable materials.
Another object of the present disclosure is to provide a process for the preparation of electrocatalyst composition.
Other objects and advantages of the present disclosure will be more apparent from the following description, which is not intended to limit the scope of the present disclosure.
SUMMARY
In one aspect of the present disclosure, it relates to an electrocatalyst composition for water splitting.
In an embodiment of the present disclosure, an electrocatalyst composition for water splitting comprises a predetermined amount of metal composite microparticles; a predetermined amount of eggshell microparticles; and a predetermined amount of a polymer substrate.
In an embodiment of the present disclosure, the electrocatalyst composition is configured to provide an oxygen evolution reaction (OER) with an over potential of 186 mV for 10 mA cm-2 and a hydrogen evolution reaction (HER) with an overpotential of 97 mV for 10 mA cm-2.
In an embodiment of the present disclosure, the electrocatalyst composition catalyzes an OER and HER in alkaline solutions.
In an embodiment of the present disclosure, the metal composite is selected from the group consisting of nickel phosphide, tungsten sulphide, nickel sulphide, cobalt oxide, and nickel chloride hexahydrate.
In an embodiment of the present disclosure, the eggshell is the dried eggshell of the hen egg.
In an embodiment of the present disclosure, polymer substrate is selected from the group consisting of polypyrrole, polyaniline, and polystyrene.
In an embodiment of the present disclosure, a predetermined particle size of the metal composite microparticles is in the range of 3 µm to 5 µm.
In an embodiment of the present disclosure, the predetermined amount of metal composite microparticles is in the range of 25 mass% to 50 mass% of the electrocatalyst composition.
In an embodiment of the present disclosure, a predetermined particle size of eggshell microparticles is in the range of 6 µm to 8µm.
In an embodiment of the present disclosure, the predetermined amount of eggshell microparticles is in the range of 25 mass% to 50 mass% of the electrocatalyst composition.
In an embodiment of the present disclosure, the predetermined amount of polymer substrate is in the range of 30 mass% to 60 mass% of the electrocatalyst composition.
In another aspect, the present disclosure relates to a process for the preparation of a polymer composition. The process comprises preparing eggshell powder, by powdering dried eggshells. The eggshell powder is washed with a first fluid medium followed by washing with a second fluid medium to obtain cleaned eggshell powder. The washed and cleaned eggshell powder is rinsed with a third fluid medium to obtain a rinsed eggshell powder. The eggshell powder is dried completely followed by powdering and sieving to obtain eggshell powder with uniformly sized particles in the range of 6 µm to 8 µm.
In an embodiment of the present disclosure, metal composite particles are added to the eggshell powder particles. The process comprises dissolving a first predetermined amount of a metal composite microparticles, along with a predetermined amount of pH adjusting agent; a predetermined amount of reagents, and a predetermined amount of the eggshell powder particles in a predetermined amount of water, and stirring for a first predetermined time period to obtain a slurry.
The pH-adjusting agent is selected from ammonium fluoride, ammonium phosphate, and ammonium bicarbonate.
The reagents are selected from urea and sodium hypophosphite monohydrate.
The slurry is subjected to heating at a first predetermined temperature for a second predetermined time period to obtain a product mixture. The product mixture is cooled followed by washing with a fourth fluid medium, and dried at a second predetermined temperature for a third predetermined time period to obtain metal composite particles with eggshell powder particles.
In an embodiment of the present disclosure, an electrocatalyst composition comprising, metal composite microparticles with eggshell powder particles and polymer substrate is obtained by using a chemical oxidative method. The process comprises dispersing a second predetermined amount of metal composite microparticles with eggshell powder microparticles and a predetermined amount of a monomer substrate in a third fluid medium and sonicating for a fourth predetermined time period.
The polymer substrate is obtained by separately dissolving an oxidizing agent in a third fluid medium to obtain an oxidizing agent solution, wherein the oxidizing agent is selected from ferric chloride (FeCl3), potassium permanganate (KMnO4), and hydrogen peroxide (H2O2). A monomer solution is added dropwise under constant stirring to the mixture of metal composite microparticles, eggshell powder microparticles, and third fluid medium; wherein the monomer is selected from pyrrole, aniline, and styrene, to obtain a corresponding polymer solution selected from polypyrrole, polyaniline, polystyrene, followed by adding the oxidizing agent solution to obtain a resultant mixture. The resultant mixture is stirred at a third predetermined temperature for a fifth predetermined time period to obtain a product. The obtained product is washed with a fourth fluid medium to obtain a washed product. The washed product is filtered and dried at a fourth predetermined temperature for a sixth predetermined time period to obtain the electrocatalyst composition.
In an embodiment of the present disclosure, the first predetermined amount of metal composite is in the range of 0.1g to 1 g in 1 mM - 2 mM concentration.
In an embodiment of the present disclosure, the predetermined amount of dried eggshell powder is in the range of 5 mg to 60 mg.
In an embodiment of the present disclosure, the second predetermined amount of metal composite with eggshell is in the range of 0.2 g to 0.5 g.
In an embodiment of the present disclosure, the predetermined amount of ammonium fluoride as the pH adjusting agent is in the range of 0.05 g to 0.2 g in 3 mM - 4 mM concentration.
In an embodiment of the present disclosure, the predetermined amount of urea is in the range of 0.1g to 1g and the predetermined amount of sodium hypophosphite monohydrate is in the range of 0.1g to 1g.
In an embodiment of the present disclosure, the concentration of urea is in the range of 7 mM to 12 mM, and that of sodium hypophosphite monohydrate is 3 mM to 7 mM.
In an embodiment of the present disclosure, the predetermined amount of monomer substrate is in the range of 20 µL to 40 µL.
In an embodiment of the present disclosure, the first fluid medium is selected from the group consisting of deionized water, demineralized water, and distilled water.
In an embodiment of the present disclosure, the second fluid medium is selected from the group consisting of dilute hydrochloric acid (HCl), orthophosphoric acid, and diluted phosphoric acid.
In an embodiment of the present disclosure, the third fluid medium is selected from deionized water, demineralized water, and distilled water.
In an embodiment of the present disclosure, the fourth fluid medium is a mixture of 95% ethanol mixed with deionized water, demineralized water, and distilled water in a 1:1 ratio.
In an embodiment of the present disclosure, the first predetermined temperature is in the range of 150 °C to 200 °C.
In an embodiment of the present disclosure, the second predetermined temperature is in the range of 40 °C to 80 °C.
In an embodiment of the present disclosure, the third predetermined temperature is in the range of 25 °C to 35 °C.
In an embodiment of the present disclosure, the fourth predetermined temperature is in the range of 55 °C to 65 °C.
In an embodiment of the present disclosure, the first predetermined time period is in the range of 15 min to 45 min.
In an embodiment of the present disclosure, the second predetermined time period is in the range of 20 hours to 28 hours.
In an embodiment of the present disclosure, the third predetermined time period is in the range of 8 hours to 16 hours.
In an embodiment of the present disclosure, the fourth predetermined time period is in the range of 15 min to 45 min.
In an embodiment of the present disclosure, the fifth predetermined time period is in the range of 10 hours to 14 hours.
In an embodiment of the present disclosure, the sixth predetermined time period is in the range of 20 hours to 28 hours.
In an embodiment of the present disclosure, the predetermined particle size of the metal composite microparticles is in the range of 3 µm to 5 µm.
In an embodiment of the present disclosure, the predetermined amount of metal composite microparticles is in the range of 25 mass% to 50 mass % of the electrocatalyst composition.
In an embodiment of the present disclosure, the predetermined particle size of eggshell microparticles is in the range of 6µm to 8µm.
In an embodiment of the present disclosure, the predetermined amount of eggshell microparticles is in the range of 25 mass% to 50 mass% of the electrocatalyst composition.
In an embodiment of the present disclosure, the predetermined amount of polymer substrate is in the range of 30 mass% to 60 mass% of the electrocatalyst composition.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING

The present disclosure will now be described with the help of the accompanying drawing, in which:
Figure 1 illustrates the schematic preparation (flow diagram) of the electrocatalyst composition of the present disclosure;
Figure 2 illustrates XRD patterns of electrocatalyst composition of the present disclosure and other catalysts;
Figure 3 illustrates the TEM image of the electrocatalyst composition of the present disclosure;
Figure 4 illustrates the SEM image of the electrocatalyst composition of the present disclosure;
Figure 5 illustrates the Linear sweep voltammetry (LSV) curves of the electrocatalyst composition of the present disclosure and other catalysts, in accordance with the present disclosure;
Figure 6 illustrates the polarization curves of the electrocatalyst composition for hydrogen and oxygen evolution reaction, in accordance with the present disclosure; and
Figure 7 illustrates the stability studies of the electrocatalyst composition, in accordance with the present disclosure.
DETAILED DESCRIPTION
The present disclosure relates to electrocatalyst composition for water splitting and the process for its preparation. In particular, the present disclosure relates to the electrocatalyst composition for the synthesis of hydrogen.
Embodiments, of the present disclosure, will now be described with reference to the accompanying drawing.
Embodiments are provided so as to thoroughly and fully convey the scope of the present disclosure to the person skilled in the art. Numerous details are set forth, relating to specific components, and methods, to provide a complete understanding of embodiments of the present disclosure. It will be apparent to the person skilled in the art that the details provided in the embodiments should not be construed to limit the scope of the present disclosure. In some embodiments, well-known processes, well-known apparatus structures, and well-known techniques are not described in detail.
The terminology used, in the present disclosure, is only for the purpose of explaining a particular embodiment and such terminology shall not be considered to limit the scope of the present disclosure. As used in the present disclosure, the forms "a," "an," and "the" may be intended to include the plural forms as well, unless the context clearly suggests otherwise. The terms "comprises," "comprising," "including," and "having," are open-ended transitional phrases and therefore specify the presence of stated features, integers, steps, operations, elements, modules, units, and/or components, but do not forbid the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The particular order of steps disclosed in the method and process of the present disclosure is not to be construed as necessarily requiring their performance as described or illustrated. It is also to be understood that additional or alternative steps may be employed.
Conventional electrocatalysts are prepared using transition metals and their compounds such as nickel, iron, cobalt, platinum, and their oxides or phosphides; perovskites; and carbon-based catalysts. These electrocatalysts for water splitting are associated with several challenges. Precious metal-based catalysts like platinum make large-scale implementation financially unfeasible increasing the cost of catalysts. Additionally, some catalysts degrade over time, requiring frequent replacements and raising environmental concerns. Moreover, while some catalysts excel at one reaction (HER or OER), they often struggle with the other, necessitating complex and expensive setups with multiple catalysts. Furthermore, the existing catalysts require significant energy input, leading to efficiency losses, and complexity in manufacturing. These drawbacks highlight the crucial need for developing cost-effective, durable, and efficient catalysts that minimize environmental impact and pave the way for the widespread adoption of water splitting as a clean energy source.
The present disclosure provides an electrocatalyst composition for water splitting and a process for its preparation.
In an aspect of the present disclosure, the present disclosure provides an electrocatalyst composition for water splitting.
In an embodiment of the present disclosure, the electrocatalyst composition for water splitting comprises a predetermined amount of metal composite microparticles; a predetermined amount of eggshell microparticles; and a predetermined amount of a polymer substrate.
In an embodiment of the present disclosure, the electrocatalyst composition is configured to provide an oxygen evolution reaction (OER) with an overpotential of 186 mV for 10 mA cm-2 and a hydrogen evolution reaction (HER) with an overpotential of 97 mV for 10 mA cm-2.
In an embodiment of the present disclosure, the electrocatalyst composition catalyzes an OER and HER in alkaline solutions.
In an embodiment of the present disclosure, the eggshell is the dried eggshell of a hen's egg, purchased from New KK Egg Center, No.21, Paada Salai Street, Senthil Nagar, Urapakkam, Chennai, Tamil Nadu- 603 210.
In an embodiment of the present disclosure, the metal composite is selected from the group consisting of nickel phosphide, tungsten sulphide, nickel sulphide, cobalt oxide, and nickel chloride hexahydrate.
In an embodiment of the present disclosure, a predetermined particle size of the metal composite microparticles is in the range of 3 µm to 5 µm.
In an embodiment of the present disclosure, the predetermined amount of metal composite microparticles is in the range of 25 mass% to 50 mass% of the electrocatalyst composition.
In an embodiment of the present disclosure, the eggshell is the dried eggshell of a hen egg.
In an embodiment of the present disclosure, a predetermined particle size of eggshell microparticles is in the range of 6 µm to 8 µm.
In an embodiment of the present disclosure, the predetermined amount of eggshell microparticles is in the range of 25 mass% to 50 mass% of the electrocatalyst composition.
In an embodiment of the present disclosure, the polymer substrate is selected from the group consisting of polypyrrole, polyaniline, and polystyrene.
In an embodiment of the present disclosure, the predetermined amount of polymer substrate is in the range of 30 mass% to 60 mass% of the electrocatalyst composition.
In another aspect, the present disclosure provides a process for the preparation of electrocatalyst composition. The process comprises the steps:
A) preparing eggshell powder, the process comprises the following steps:
i) powdering dried eggshells;
ii) washing the eggshell powder with a first fluid medium followed by washing with a second fluid medium to obtain cleaned eggshell powder;
iii) rinsing the washed and cleaned eggshell powder with a third fluid medium to obtain a rinsed eggshell powder;
iv) drying the eggshell powder completely, followed by powdering and sieving to obtain eggshell powder with uniformly sized particles in the range of 6 µm to 8 µm ;
B) adding metal composite particles to the eggshell powder particles, the process comprises the following steps;
v) dissolving a first predetermined amount of a metal composite microparticles, along with a predetermined amount of pH adjusting agent; a predetermined amount of reagents, and a predetermined amount of the eggshell powder particles in a predetermined amount of water, and stirring for a first predetermined time period to obtain a slurry; wherein,
the pH-adjusting agent is selected from ammonium fluoride, ammonium phosphate, and ammonium bicarbonate;
the reagents are selected from urea and sodium hypophosphite monohydrate;
vi) subjecting the slurry to heating at a first predetermined temperature for a second predetermined time period to obtain a product mixture;
vii) cooling the product mixture; washing with a fourth fluid medium, and drying at a second predetermined temperature for a third predetermined time period to obtain metal composite particles with eggshell powder particles;
C) obtaining an electrocatalyst composition comprising, metal composite particles with eggshell powder particles and polymer substrate by using a chemical oxidative method, the process comprises the following steps:
viii) dispersing a second predetermined amount of metal composite microparticles with eggshell powder microparticles and a predetermined amount of a monomer substrate in a third fluid medium and sonicating for a fourth predetermined time period;
wherein the polymer substrate is obtained by following steps;
a) separately dissolving an oxidizing agent in a third fluid medium to obtain an oxidizing agent solution; wherein the oxidizing agent is selected from ferric chloride (FeCl3), potassium permanganate (KMnO4), and hydrogen peroxide (H2O2);
b) adding a monomer solution dropwise under constant stirring to the mixture of metal composite microparticles, eggshell powder microparticles, and third fluid medium; wherein the monomer is selected from pyrrole, aniline, and styrene, to obtain a corresponding polymer solution selected from polypyrrole, polyaniline, polystyrene, followed by adding the oxidizing agent solution to obtain a resultant mixture;
ix) stirring the resultant mixture at a third predetermined temperature for a fifth predetermined time period to obtain a product;
x) washing the obtained product with a fourth fluid medium to obtain a washed product;
xi) filtering and drying the washed product at a fourth predetermined temperature for a sixth predetermined time period to obtain the electrocatalyst composition.
The process is described in detail.
In the first step, eggshell powder is prepared by powdering dried eggshells.
The eggshell powder is washed with a first fluid medium followed by washing with a second fluid medium to obtain cleaned eggshell powder. The washed and cleaned eggshell powder is rinsed with a third fluid medium to obtain a rinsed eggshell powder. The eggshell powder is dried completely followed by powdering and sieving to obtain eggshell powder with uniformly sized particles in the range of 6 µm to 8 µm.
In an embodiment of the present disclosure, the first fluid medium is selected from the group consisting of deionized water, demineralized water, and distilled water.
In an embodiment of the present disclosure, the second fluid medium is selected from the group consisting of dilute hydrochloric acid (HCl), orthophosphoric acid, and diluted phosphoric acid.
In an embodiment of the present disclosure, the third fluid medium is selected from deionized water, demineralized water, and distilled water.
In the second step, metal composite particles are added to the eggshell powder particles.
The process comprises dissolving a first predetermined amount of a metal composite microparticles, along with a predetermined amount of pH adjusting agent; a predetermined amount of reagents, and a predetermined amount of the eggshell powder particles in a predetermined amount of water, and stirring for a first predetermined time period to obtain a slurry. The slurry is subjected to heating at a first predetermined temperature for a second predetermined time period to obtain a product mixture. The product mixture is cooled followed by washing with a fourth fluid medium, and dried at a second predetermined temperature for a third predetermined time period to obtain metal composite particles with eggshell powder particles. The pH-adjusting agent is selected from ammonium fluoride, ammonium phosphate, and ammonium bicarbonate.
The reagents are selected from urea and sodium hypophosphite monohydrate.
In an embodiment of the present disclosure, the predetermined particle size of the metal composite microparticles is in the range of 3 µm to 5 µm.
In an embodiment of the present disclosure, the first predetermined amount of metal composite is in the range of 0.1g to 1 g in 1 mM - 2 mM concentration. In an exemplary embodiment of the present disclosure, the first predetermined amount of metal composite is 0.35g in 1 mM - 2 mM concentration.
In an embodiment of the present disclosure, the predetermined particle size of eggshell microparticles is in the range of 6µm to 8µm.
In an embodiment of the present disclosure, the predetermined amount of dried eggshell powder is in the range of 5 mg to 60 mg. In an exemplary embodiment of the present disclosure, the predetermined amount of dried eggshell powder is 40 mg.
In an embodiment of the present disclosure, the predetermined amount of ammonium fluoride as the pH adjusting agent is in the range of 0.05 g to 0.2 g in 3 mM-4 mM concentration. In an exemplary embodiment of the present disclosure, the predetermined amount of ammonium fluoride as the pH adjusting agent is 0.1 g in 3 mM - 4 mM concentration.
In an embodiment of the present disclosure, the predetermined amount of urea is in the range of 0.1g to 1g and sodium hypophosphite monohydrate is in the range of 0.1g to 1g. In an exemplary embodiment of the present disclosure, the predetermined amount of urea is in the range of 0.5g. In an exemplary embodiment of the present disclosure, the predetermined amount of sodium hypophosphite monohydrate is 0.5 g.
In an embodiment of the present disclosure, the concentration of urea is in the range of 7 mM to 12 mM, and that of sodium hypophosphite monohydrate is 3 mM to 7 mM.
In an embodiment of the present disclosure, the first predetermined time period is in the range of 15 min to 45 min.
In an embodiment of the present disclosure, the first predetermined temperature is in the range of 150 °C to 200 °C.
In an embodiment of the present disclosure, the second predetermined time period is in the range of 20 hours to 28 hours.
In an embodiment of the present disclosure, the second predetermined temperature is in the range of 40 °C to 80 °C.
In an embodiment of the present disclosure, the third predetermined time period is in the range of 8 hours to 16 hours.
In the third step, an electrocatalyst composition comprising, metal composite particles with eggshell powder particles and polymer substrate is obtained by using a chemical oxidative method.
The process comprises dispersing a second predetermined amount of metal composite microparticles with eggshell powder microparticles and a predetermined amount of a monomer substrate in a third fluid medium and sonicating for a fourth predetermined time period.
The polymer substrate is obtained by separately dissolving an oxidizing agent in a third fluid medium to obtain an oxidizing agent solution, wherein the oxidizing agent is selected from ferric chloride (FeCl3), potassium permanganate (KMnO4), and hydrogen peroxide (H2O2). A monomer solution is added dropwise under constant stirring to the mixture of metal composite microparticles, eggshell powder microparticles, and third fluid medium; wherein the monomer is selected from pyrrole, aniline, and styrene, to obtain a corresponding polymer solution selected from polypyrrole, polyaniline, polystyrene, followed by adding the oxidizing agent solution to obtain a resultant mixture. The resultant mixture is stirred at a third predetermined temperature for a fifth predetermined time period to obtain a product. The obtained product is washed with a fourth fluid medium to obtain a washed product. The washed product is filtered and dried at a fourth predetermined temperature for a sixth predetermined time period to obtain the electrocatalyst composition.
In an embodiment of the present disclosure, the second predetermined amount of metal composite with eggshell is in the range of 0.2 g to 0.5 g. In an exemplary embodiment of the present disclosure, the second predetermined amount of metal composite with eggshell is 0.397 g.
In an embodiment of the present disclosure, the predetermined amount of monomer substrate is in the range of 20 µL to 40 µL. In an exemplary embodiment of the present disclosure, the predetermined amount of pyrrole is 30 µL.
In an embodiment of the present disclosure, the third fluid medium is selected from deionized water, demineralized water, and distilled water.
In an embodiment of the present disclosure, the fourth fluid medium is a mixture of 95% ethanol mixed with deionized water, demineralized water, and distilled water in a 1:1 ratio.
In an embodiment of the present disclosure, the fourth predetermined time period is in the range of 15 min to 45 min.
In an embodiment of the present disclosure, the third predetermined temperature is in the range of 25 °C to 35 °C.
In an embodiment of the present disclosure, the fifth predetermined time period is in the range of 10 hours to 14 hours.
In an embodiment of the present disclosure, the fourth predetermined temperature is in the range of 55 °C to 65 °C.
In an embodiment of the present disclosure, the sixth predetermined time period is in the range of 20 hours to 28 hours.
In an embodiment of the present disclosure, the predetermined amount of metal composite microparticles is in the range of 25 mass% to 50 mass % of the electrocatalyst composition.
In an embodiment of the present disclosure, the predetermined amount of eggshell microparticles is in the range of 25 mass% to 50 mass% of the electrocatalyst composition.
In an embodiment of the present disclosure, the predetermined amount of polymer substrate is in the range of 30 mass% to 60 mass% of the electrocatalyst composition.
In an embodiment of the present disclosure, the technique of incorporating Ni5P4 microparticles with eggshell powder through a hydrothermal process provides a distinctive and efficient method for improving the material's catalytic properties, underlining its role in advancing electrocatalytic technologies.
The inclusion of eggshell powder, an easily accessible and environmentally friendly waste material, promotes environmental sustainability and improves the catalyst's stability.
In an embodiment of the present disclosure, incorporating polypyrrole serves a dual function, ensuring both the structural strength and conductivity of the Ni5P4 microparticles. These distinctive blends of materials represent a novel and innovative approach to hydrogen generation applications.
In an embodiment of the present disclosure, the composition of Nickel phosphide, eggshell powder, and polypyrrole demonstrates enhanced performance in catalyzing water-splitting reactions, signifying its effectiveness in utilizing renewable energy through electrocatalysis.
The inclusion of eggshell powder and polypyrrole not only boosts the electrocatalyst's activity and kinetics for water splitting but also ensures prolonged durability over a 100-hour duration, indicating its potential for consistent and reliable performance. The electrocatalyst composition thus provides both efficiency and durability.
In an embodiment of the present disclosure, the electrocatalyst composition of the present disclosure provides an economically efficient and effective electrocatalyst composition, specifically engineered for electrochemical water splitting, comprising nickel phosphide with eggshell powder and supported by polypyrrole (Ni5P4@ES/PPy).
The electrocatalyst composition of the present disclosure has the potential to be used in a variety of clean energy applications, including:
Hydrogen production through water splitting: The catalyst excels at both hydrogen evolution and oxygen evolution, making it efficient for splitting water into hydrogen, a clean and sustainable fuel.
Electrolysis systems: The catalyst can function effectively as both the cathode and anode in an electrolyzer, simplifying the design and potentially improving the efficiency of these systems for hydrogen production.
Fuel cells: The catalyst's performance in hydrogen evolution makes it a promising candidate for fuel cells, which rely on this reaction for efficient energy conversion.
Energy-saving processes: The catalyst's ability to split water with a lower voltage than usual suggests it could be useful in processes that aim to minimize energy input, contributing to more sustainable technologies.
The foregoing description of the embodiments has been provided for purposes of illustration and is not intended to limit the scope of the present disclosure. Individual components of a particular embodiment are generally not limited to that particular embodiment, but, are interchangeable. Such variations are not to be regarded as a departure from the present disclosure, and all such modifications are considered to be within the scope of the present disclosure.
The present disclosure is further described in light of the following non-limiting examples featured through certain experiments, which are set forth for illustration purposes only and not to be construed as limiting the scope of the disclosure. The following experiments can be scaled up to an industrial/commercial scale and the results obtained can be extrapolated to an industrial scale.

EXAMPLES
Example 1: Preparation of electrocatalyst composition of the present disclosure
Synthesis of Ni5P4@ES via hydrothermal approach
Step 1- Preparation of eggshell (ES) powder
The eggs were purchased from local stores and eggshells (ES) were purchased from New KK Egg Center, No.21, Paada Salai Street, Senthil Nagar, Urapakkam, Chennai, Tamil Nadu- 603 210. The ES were washed thoroughly with tap water and then with dilute HCl to remove impurities. The washed ES were then rinsed with D.I. water, dried, powdered, and sieved to get uniformly sized particles in the range of 6µm to 8µm.
Step 2- Preparation of metal composite microparticles with eggshell powder
The metal composite microparticles are incorporated into the eggshell powder by using hydrothermal synthesis to obtain metal composite microparticles with eggshell powder particles (Ni5P4@ES).
0.35 g of Nickel chloride hexahydrate (NiCl2.6H2O) (1.5 mM), 0.12 g of ammonium fluoride (NH4F) (3.5 mM), 0.54 g of urea (9 mM), 0.52 g sodium hypophosphite monohydrate (NaH2PO2.H2O) (5 mM), and 40 mg of ES powder were dissolved in 35 mL of water and stirred for 30 minutes to obtain a slurry. The slurry was transferred into a 50 mL Teflon autoclave and heated at 180oC for 24 hours to obtain a product mixture. The product mixture was cooled and was washed with D.I. water and ethanol (1:1, 30mL) solution, dried at 60oC for 12 hours to obtain metal composite particles with eggshell powder (Ni5P4@ES).
For comparison, Ni5P4 without ES was prepared without introducing ES with the same method.

Step 3- Synthesis of Ni5P4@ES/PPy

Polymerization of Pyrrole was done by oxidative chemical polymerization method 30 µL of pyrrole were dispersed in 6 mL of D.I water added dropwise to the 0.397 g of Ni5P4@ES and sonicated for 30 minutes to obtain a mixture.
In a separate beaker, 70.2 mg of FeCl3 was dissolved in 6 mL D.I. water. The FeCl3 solution was added dropwise to the mixture of pyrrole and Ni5P4@ES under constant stirring to obtain a resultant mixture. The resultant mixture was stirred at room temperature (30 oC) for 12 hours to obtain a product. The product obtained was washed several times with D.I. water and ethanol (1:1, 30mL) solution to obtain a washed product. The washed product was filtered and dried at 60oC for 24 hours to obtain the electrocatalyst composition (Ni5P4@ES/PPy).
Ni5P4/PPy was prepared using the same method without the incorporation of ES.

Example 2: Characterization of the electrocatalyst composition
The electrocatalyst composition of the present disclosure was characterized using XRD, TEM, and SEM analyses and compared with Ni5P4, Ni5P4@ES, and Ni5P4/PPy. The results are illustrated in Figures 2, 3, and 4.
a) Figure 2 illustrates XRD patterns of the electrocatalyst composition of the present disclosure and other catalysts. The crystallographic features of Ni5P4, Ni5P4@ES, Ni5P4/PPy, and Ni5P4@ES/PPy are illustrated in the X-ray diffraction pattern, with prominent peaks at 22.15°, 30.37°, 31.47°, 32.57°, 36.05°, 40.56°, 49.75°, 51.91°, 52.29°, 52.97°, 53.99°, and 56.36° corresponding to the (102), (200), (201), (004), (104), (210), (006), (205), (106), (214), (220), and (310) crystal faces of Ni5P4 (JCPDS 89-2588). The presence of ES powder in Ni5P4@ES and Ni5P4@ES/PPy is confirmed by a distinctive peak at 29.04°. Ni5P4/PPy and Ni5P4@ES/PPy exhibit weaker intensity and broader full width at half maxima in their diffraction peaks, indicating reduced crystallinity and smaller crystallite size due to the amorphous nature of PPy.
b) The effective integration of Ni5P4 on ES and PPy is further validated using a transmission electron microscopic (TEM) image, in which the Ni5P4 particle is coated with PPy and ES. Figure 3 illustrates the TEM image of the electrocatalyst composition of the present disclosure and other catalysts.
c) The morphology and elemental composition of pristine Ni5P4, Ni5P4@ES, Ni5P4/PPy, and Ni5P4@ES/PPy are analyzed by scanning electron microscopic (SEM) images. The composite Ni5P4@ES/PPy, as shown in Figure 4, comprises abundant Ni5P4 microspheres embedded on the ES surface, incorporated in the PPy matrix.

Example 3: Electrochemical studies
The performance of the electrochemical catalyst composition of the present disclosure was evaluated by using an electrochemical station, Biologic SP-150.
The HER and OER tests were performed in 1 M KOH solution utilizing a three-electrode setup, wherein Hg/HgO (1 M KOH) and graphite rod were employed as the reference and counter electrode, respectively. The nickel foam was cleaned, dried, and modified with the synthesized Ni5P4@ES/PPy as follows. Different amount of the catalyst (1mg, 2mg, 3mg, 4mg, and 5mg) was homogenized with a 1 mL solution of water-Nafion-ethanol (taken in 6:3:1 volume ratio) by sonicating for 15 min. About 15μL of the homogenized ink was cast on 1 X 1 cm2 nickel foam and dried at ambient conditions for 10 hours. These modified electrodes were used as working electrodes during all electrochemical measurements and characterizations which were done at ambient conditions.
All potentials were converted to the reversible hydrogen electrode (RHE) scale. The HER and OER performance were analyzed using linear sweep voltammetry (LSV) at a scan rate of 5 mVs-1 from -0.5 to -1.5 V and 0.5 to 2.0 V vs. Hg/HgO. The Electrochemical Impedance Spectroscopy (EIS) test was conducted from 1 kHz to 1 mHz to investigate the charge transfer ability of the as-prepared catalyst. The electrochemical active surface area (ECSA) was studied using cyclic voltammetry with a scan rate of 20 to 100 mV s-1 at non-faradaic region. The overall water splitting performance was carried out in a two-electrode system, where Ni5P4@ES/PPy/NF electrodes were taken as both cathode and anode, in 1 M KOH solution. Linear sweep voltammetry (LSV) was tested at a scan rate of 5 mV s-1 from 1.0 V to 1.9 V, respectively.
Figure 5 illustrates the Linear sweep voltammetry (LSV) curves of the electrocatalyst composition of the present disclosure and other catalysts.
It can be observed from Figure 5 that, utilizing Ni5P4@ES/PPy as both the cathode and anode in a water-splitting setup, its electrocatalytic performance was thoroughly evaluated in 1 M KOH electrolyte through LSV curves at a scan rate of 5 mV/s. The results demonstrated that the Ni5P4@ES/PPy|Ni5P4@ES/PPy configuration achieved an impressive cell voltage of 1.52 V at a current density of 10 mA/cm². This performance notably surpasses that of the benchmark catalysts Pt-C/NF|RuO2/NF, which recorded a cell voltage of 1.60 V under the same conditions. These findings highlight the potential of Ni5P4@ES/PPy as a highly efficient catalyst system for water-splitting applications.
Example 4:
Electrochemical Performance
The electrochemical activity of the electrocatalyst composition of the present disclosure and pristine Ni5P4 catalyst was evaluated for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) under alkaline conditions. In a 1M KOH solution, the catalyst of the present disclosure demonstrates overpotentials of 97 mV and 186 mV for HER and OER, respectively, surpassing the performance of pristine Nickel phosphide microspheres (Ni5P4). The enhanced activity emphasizes the effectiveness of the catalyst of the present disclosure in catalyzing essential electrochemical reactions for water-splitting applications. The HER and OER activity was illustrated in Figure 6.
Table 1 shows a Comparison of the electrocatalytic performance of reported OER catalysts with Ni5P4@ES/PPy/NF in alkaline media at 10 mA/cm2.
Table 1: Comparison of electrocatalytic performance of reported OER catalysts with Ni5P4@ES/PPy/NF in alkaline media at 10 mA/cm2

Examples Catalysts Overpotential
(Ƞ)@10 mA/cm2
Electrocatalyst composition prepared in accordance with the present disclosure Ni5P4@ES/PPy 186
Comparative Example 1 FeNiP 193
Comparative Example 2 Ni5P4@FeP 205
Comparative Example 3 Fe-Ni5P4/NiFeOH-350 221
Comparative Example 4 Fe-NiP 223
Comparative Example 5 Fe-Ni5P4/Fe-Ni2P 231
Comparative Example 6 Ni2P-Ni5P4 238
Comparative Example 7 Ru/B-Ni2P/Ni5P4 270
Comparative Example 8 Fe-Ni2P/Ni5P4@N-C 280
Comparative Example 9 NiMnOP 290

Table 2: Comparison of electrocatalytic performance of reported HER catalysts with Ni5P4@ES/PPy/NF in alkaline media at 10 mA/cm2
Examples Catalysts Overpotential
(Ƞ)@10 mA/cm2
Electrocatalyst composition prepared in accordance with the present disclosure Ni5P4@ES/PPy 97
Comparative Example 1 FeNiP 101
Comparative Example 2 Ni5P4@FeP 105
Comparative Example 3 Fe-Ni5P4/NiFeOH-350 105
Comparative Example 4 Fe-NiP 107
Comparative Example 5 Fe-Ni5P4/Fe-Ni2P 137
Comparative Example 6 Ni2P-Ni5P4 144
Comparative Example 7 Ru/B-Ni2P/Ni5P4 195
Comparative Example 8 Fe-Ni2P/Ni5P4@N-C 197
Comparative Example 9 NiMnOP 200

It can be observed from Table 1, Table 2, and Figure 6 that Ni5P4@ES/PPy demonstrates competitive activity and efficiency, which positions it favorably among its counterparts. By effectively leveraging the unique properties of the as-prepared catalyst, it not only matches but may also offer advantages over previously reported materials, thereby enhancing the potential for its application in electrocatalytic processes. Such findings suggest that Ni5P4@ES/PPy could play a significant role in advancing the development of efficient catalysts for energy conversion technologies.
Example 5: Stability
The i-t curves illustrated in Fig. 7 reveal that the Ni5P4@ES/PPy/NF electrode exhibits exceptional stability during a prolonged operational period of 40 hours at a current density of 10 mA/cm². This performance indicates not only the robustness of the Ni5P4@ES/PPy/NF structure but also its effective response to electrochemical demands under alkaline conditions. The sustained current output without significant degradation highlights the potential of Ni5P4@ES/PPy as a promising electrode material for symmetric water electrolyzers, where long-term operational stability is crucial for practical applications.
The stability study was carried out by studying the durability of electrocatalyst composition activity.
The electrocatalyst composition of the present disclosure demonstrates durability by retaining its electrocatalyst activity for over 40-hour duration.
Table 3: Stability studies
Example Material Cell voltage Stability
Electrocatalyst prepared in accordance with the present disclosure Nickel phosphide microparticles with egg shell powder particles and polymer substrate Ni5P4@ES/PPy 1.52 V 40 hours
Comparative Example 1 Nickel Manganese oxyphosphide
NiMnOP 1.53 35 hours
Comparative Example 2 Iron doped Nickel phosphide / Iron doped Nickel hydroxide
Fe-Ni5P4/NiFeOH 1.55 30 hours
Comparative Example 3 Nickel phosphide heterointerface
Ni2P-Ni5P4 1.69 12 hours

TECHNICAL ADVANCEMENT
The present disclosure described herein above has several technical advantages including, but not limited to, the realization of an electrocatalyst composition, that
• provides enhanced electrochemical performance;
• requires ultra-low cell voltage for water splitting thus reducing energy consumption;
• possesses enduring sustainability for outstanding stability over a prolonged period;
• enhanced OER and HER performance; and
• uses eggshell material that reduces the cost of the electrocatalyst composition;
a process for preparing the electrocatalyst composition that is
• simple process for the preparation of catalyst composition; and
• cost-effective.
Throughout this specification the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers, or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.
The use of the expression "at least" or "at least one" suggests the use of one or more elements or ingredients or quantities, as the use may be in the embodiment of the disclosure to achieve one or more of the desired objects or results. Any discussion of documents, acts, materials, devices, articles, or the like that has been included in this specification is solely for the purpose of providing a context for the disclosure. It is not to be taken as an admission that any or all of these matters form a part of the prior art base or were common general knowledge in the field relevant to the disclosure as it existed anywhere before the priority date of this application.
The numerical values mentioned for the various physical parameters, dimensions, or quantities are only approximations and it is envisaged that the values higher/lower than the numerical values assigned to the parameters, dimensions or quantities fall within the scope of the disclosure, unless there is a statement in the specification specific to the contrary. While considerable emphasis has been placed herein on the components and component parts of the preferred embodiments, it will be appreciated that many embodiments can be made and that many changes can be made in the preferred embodiments without departing from the principles of the disclosure. These and other changes in the preferred embodiment as well as other embodiments of the disclosure will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the disclosure and not as a limitation.   , Claims:WE CLAIM:
1. An electrocatalyst composition for water splitting, said electrocatalyst composition comprises:
a. a predetermined amount of a metal composite microparticles;
b. a predetermined amount of eggshell microparticles; and
c. a predetermined amount of a polymer substrate.
wherein:
said electrocatalyst composition is configured to provide oxygen evolution reaction (OER) with an overpotential of 186 mV for 10 mA cm-2 and hydrogen evolution reaction (HER) with an overpotential of 97 mV for 10 mAcm-2; and
catalyzes an OER and HER in alkaline solutions.
2. The electrocatalyst composition as claimed in claim 1, wherein said metal composite is selected from the group consisting of nickel phosphide, tungsten sulphide, nickel sulphide, cobalt oxide, and nickel chloride hexahydrate.
3. The electrocatalyst composition as claimed in claim 1, wherein said eggshell is the dried eggshell of a hen egg.
4. The electrocatalyst composition as claimed in claim 1, wherein said polymer substrate is selected from the group consisting of polypyrrole, polyaniline, and polystyrene.
5. The electrocatalyst composition as claimed in claim 1, wherein:
 the predetermined particle size of said metal composite microparticles is in the range of 3 µm to 5 µm;
 the predetermined amount of metal composite microparticles is in the range of 25 mass% to 50 mass% of said electrocatalyst composition;
 the predetermined particle size of eggshell microparticles is in the range of 6 µm to 8µm;
 the predetermined amount of eggshell microparticles is in the range of 25 mass% to 50 mass% of said electrocatalyst composition, and
 the predetermined amount of polymer substrate is in the range of 30 mass% to 60 mass% of said electrocatalyst composition.
6. A process for preparing an electrocatalyst composition, said process comprising the steps:
A) preparing eggshell powder, said process comprises the following steps:
i) powdering dried eggshells;
ii) washing said eggshell powder with a first fluid medium followed by washing with a second fluid medium to obtain cleaned eggshell powder;
iii) rinsing said washed and cleaned eggshell powder with a third fluid medium to obtain a rinsed eggshell powder;
iv) drying said eggshell powder completely, followed by powdering and sieving to obtain eggshell powder with uniformly sized particles in the range of 6 µm to 8 µm ;

B) adding metal composite particles to said eggshell powder particles, said process comprises the following steps;
v) dissolving a first predetermined amount of a metal composite microparticles, along with a predetermined amount of pH adjusting agent; a predetermined amount of reagents, and a predetermined amount of said eggshell powder particles in a predetermined amount of water, and stirring for a first predetermined time period to obtain a slurry; wherein,
said pH adjusting agent is selected from ammonium fluoride, ammonium phosphate, and ammonium bicarbonate;
said reagents are selected from urea and sodium hypophosphite monohydrate;
vi) subjecting said slurry to heating at a first predetermined temperature for a second predetermined time period to obtain a product mixture;
vii) cooling said product mixture; washing with a fourth fluid medium, and drying at a second predetermined temperature for a third predetermined time period to obtain metal composite particles with eggshell powder particles;
C) obtaining an electrocatalyst composition comprising, metal composite microparticles with eggshell powder particles and polymer substrate by using a chemical oxidative method, said process comprises the following steps:
viii) dispersing a second predetermined amount of metal composite microparticles with eggshell powder microparticles and a predetermined amount of a monomer substrate in a third fluid medium and sonicating for a fourth predetermined time period;
wherein said polymer substrate is obtained by following steps;
c) separately dissolving an oxidizing agent in a third fluid medium to obtain an oxidizing agent solution; wherein said oxidizing agent is selected from ferric chloride (FeCl3), potassium permanganate (KMnO4), and hydrogen peroxide (H2O2);
d) adding a monomer solution dropwise under constant stirring to the mixture of metal composite microparticles, eggshell powder microparticles, and third fluid medium; wherein said monomer is selected from pyrrole, aniline, and styrene, to obtain a corresponding polymer solution selected from polypyrrole, polyaniline, polystyrene, followed by adding said oxidizing agent solution to obtain a resultant mixture;
ix) stirring said resultant mixture at a third predetermined temperature for a fifth predetermined time period to obtain a product;
x) washing said obtained product with a fourth fluid medium to obtain a washed product;
xi) filtering and drying said washed product at a fourth predetermined temperature for a sixth predetermined time period to obtain said electrocatalyst composition.

7. The process as claimed in claim 6, wherein:
• said first predetermined amount of metal composite is in the range of 0.1g to 1 g in 1 mM - 2 mM concentration;
• said predetermined amount of dried eggshell powder is in the range of 5 mg to 60 mg;
• said second predetermined amount of metal composite with eggshell is in the range of 0.2 g to 0.5 g;
• said predetermined amount of ammonium fluoride as the pH adjusting agent is in the range of 0.05 g to 0.2 g in 3 mM - 4 mM concentration;
• said predetermined amount of urea is in the range of 0.1g to 1g and sodium hypophosphite monohydrate is in the range of 0.1g to 1g;
o wherein the concentration of urea is in the range of 7 mM to 12 mM, and
o the concentration of sodium hypophosphite monohydrate is 3 mM to 7 mM;
• said predetermined amount of monomer substrate is in the range of 20 µL to 40 µL;
• said first fluid medium is selected from the group consisting of deionized water, demineralized water, and distilled water;
• said second fluid medium is selected from the group consisting of dilute hydrochloric acid (HCl), ortho phosphoric acid, and dilute phosphoric acid; and
• said third fluid medium is selected from deionized water, demineralized water, and distilled water; and
• said fourth fluid medium is a mixture of 95% ethanol mixed with deionized water, demineralized water, and distilled water in a 1:1 ratio.
8. The process as claimed in claim 6, wherein:
• said first predetermined temperature is in the range of 150 °C to 200 °C;
• said second predetermined temperature is in the range of 40 °C to 80 °C;
• said third predetermined temperature is in the range of 25 °C to
35 °C; and
• said fourth predetermined temperature is in the range of 55 °C to 65 °C.
9. The process as claimed in claim 6, wherein:
• said first predetermined time period is in the range of 15 minutes to 45 minutes;
• said second predetermined time period is in the range of 20 hours to 28 hours;
• said third predetermined time period is in the range of 8 hours to 16 hours;
• said fourth predetermined time period is in the range of 15 minutes to 45 minutes;
• said fifth predetermined time period is in the range of 10 hours to 14 hours; and
• said sixth predetermined time period is in the range of 20 hours to 28 hours.
10. The process as claimed in claim 6, wherein:
• said predetermined particle size of said metal composite microparticles is in the range of 3 µm to 5 µm;
• said predetermined amount of metal composite microparticles is in the range of 25 mass% to 50 mass % of said electrocatalyst composition;
• said predetermined particle size of egg shell microparticles is in the range of 6µm to 8µm;
• said predetermined amount of egg shell microparticles is in the range of 25 mass% to 50 mass% of said electrocatalyst composition; and
• said predetermined amount of polymer substrate is in the range of 30 mass% to 60 mass% of said electrocatalyst composition.


Dated this 18th day of November, 2024

_______________________________
MOHAN RAJKUMAR DEWAN, IN/PA - 25
OF R. K. DEWAN & CO.
AUTHORIZED AGENT OF APPLICANT

TO,
THE CONTROLLER OF PATENTS
THE PATENT OFFICE, CHENNAI

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