A METHOD FOR PREPARING TRANSITION METAL DICHALCOGENIDES (TMDCs)-BASED HETEROSTRUCTURE ELECTROCATALYSTS FOR EFFICIENT HYDROGEN PRODUCTION

Abstract

The present invention provides a method for preparing transition metal dichalcogenides (TMDCs)-based heterostructure electrocatalysts for efficient hydrogen production. The method includes synthesizing TMDCs such as WS₂, WSe₂, and Ru-doped WS₂. These materials are applied onto a carbon cloth substrate by mixing them with N-methylpyrrolidone (NMP) to form a homogeneous paste, which is then coated on the carbon cloth (CC) substrate. The coated CC is dried at 200°C for 1 hour under an inert atmosphere. The method further involves layering the synthesized TMDCs on the dried substrate and heating at 200°C to form the TMDC-based heterostructures. The resulting heterostructures include Ru-WS₂/WSe₂ and WS₂/WSe₂, which offer enhanced catalytic performance for hydrogen evolution reactions (HER). This approach results in high-performance, durable, and cost-effective electrocatalysts for sustainable hydrogen production, offering an alternative to precious noble metal-based catalysts like platinum. FIG. 1

Specification

Description:BACKGROUND
Technical Field
[0001] The present invention relates to the field of materials science and energy technology. Specifically, it pertains to a cost-effective and a scalable method for producing transition metal dichalcogenide (TMDC) heterostructures to enhance the performance of electrocatalysts in hydrogen evolution reactions (HER).
Description of the Related Art
[0002] The increase in environmental pollution by the consumption of fossil fuels such as coal, oil, and natural gas creates serious issues like global warming, ecological contamination, and energy crisis. The majority of nations have made significant progress in promoting the development of different renewable energy sources, such as wind, solar, biomass, and hydropower. Hydrogen is the attracted zero-carbon renewable energy carrier, which results in zero carbonaceous species emissions, greatly reducing ecological disturbances. The hydrogen generated from electrochemical water splitting is a promising approach to produce green hydrogen with non-carbonous emissions. In electrochemical water splitting, two half reactions occur in the entire system, one at the cathode side called hydrogen evolution reaction (HER), and the other at the anode, called oxygen evolution reaction (OER). Hydrogen can be produced through water electrolysis using four basic technologies such as proton-exchange membrane (PEM), anion-exchange membrane (AEM), alkaline water electrolysis (AWE), and solid oxide electrolysis (SOE). The alkaline water electrolysis (AWE) has emerged as a leading technology in industrialization, boosting into robustness and reliability that make it an attractive solution for various applications. At present, the elements such as Pt and Pd are recognized as attractive catalysts for HER. However, their use in the large-scale commercial market is hindered by its high cost (greater than 30 USD per gram) and scarcity of less than 0.005 ppm for Pt and 0.001 for Pd in the Earth's crust. Therefore, it is essential to develop alternative inexpensive, earth-abundant, highly conductive, and highly electrochemically active materials. The components selection and also construction of the electro-catalysts's structure play an advancement in the active sites towards the H2 generation. Low-dimensional materials, particularly two-dimensional (2D) transition metal dichalcogenides (TMDCs), have emerged as promising candidates for next-generation electronics, optoelectronics, energy conversion, and storage technologies. However, WS₂ and other TMDCs face significant limitations stemming from van der Waals interactions between layers, which reduce the number of active edge sites and restrict charge transfer efficiency, leading to suboptimal catalytic performance compared to traditional catalysts like platinum (Pt).
[0003] To address these challenges, various strategies such as phase engineering, doping, morphology modulation, and interfacial engineering have been explored. Among these, heterostructure formation has proven to be a promising approach, enhancing active surface areas, improving charge transfer efficiency, and increasing electronic conductivity through the efficient recombination of electrons and holes. However, these existing methods for heterostructure synthesis, including chemical vapor deposition (CVD) and physical vapor deposition (PVD), present challenges in terms of complexity, high cost, and scalability. These techniques often require precise control over conditions and are resource-intensive, limiting their use for large-scale production. Additionally, interfacial stability remains a concern in some heterostructures, particularly under harsh operational conditions, leading to performance degradation over time. While doping and phase engineering can improve catalytic efficiency, they often involve expensive materials or complex processes, increasing production costs and resulting in inconsistent performance.
[0004] Therefore, there arises a need to address the aforementioned technical drawbacks in existing technologies by developing a method for the efficient and scalable fabrication of transition metal dichalcogenide (TMDC)-based heterostructures. This method should overcome the limitations associated with current synthesis techniques, such as the high cost and complexity of chemical vapor deposition (CVD) and physical vapor deposition (PVD).
SUMMARY OF THE INVENTION
[0005] The objective of the present invention is to design and develop electrocatalysts based on TMDCs for electrochemical water splitting, aiming to replace noble metal-based catalyst like Pt and enhance the sustainability of hydrogen production through the HER process.
[0006] The first aspect of the present invention provides a method for preparing transition metal dichalcogenides (TMDCs)-based heterostructure electrocatalysts for efficient hydrogen production. The method includes the steps of (i) synthesizing transition metal dichalcogenides (TMDCs) including WS₂, WSe₂, and Ru-doped WS₂ using a solid state reaction technique, (ii) coating a carbon cloth (CC) substrate with the synthesized transition metal dichalcogenides (TMDCs) by applying one of the synthesized transition metal dichalcogenides (TMDCs) including WS₂, WSe₂, and Ru-doped WS₂ onto the carbon cloth substrate and drying under controlled conditions, the synthesized transition metal dichalcogenides (TMDCs) are mixed with N-methylpyrrolidone (NMP) to form a homogeneous paste for applying on the carbon cloth substrate, (iii) the carbon cloth substrate applied with the synthesized transition metal dichalcogenides (TMDCs) are dried at 200°C for 1 hour under an inert atmosphere, (iv) layering one of the synthesized transition metal dichalcogenides (TMDCs) including WS₂, WSe₂, and Ru-doped WS₂ on the coated carbon cloth and heating at 200°C to prepare the TMDC-based heterostructures, the TMDC-based heterostructure is a Ru-WS2/WSe2 heterostructure or WS2/WSe2 heterostructure.
[0007] In some embodiments, the Ru-WS2/WSe2 heterostructure is prepared by (i) coating the Ru-WS2 paste on the carbon cloth substrate, (ii) drying the coated cloth substrate at 200°C for 1 hour under the inert atmosphere, and (iii) layering the coated carbon cloth substrate with the WSe2 paste, and heating at 200°C to get the Ru-WS2/WSe2 heterostructure.
[0008] In some embodiments, the WS2/WSe2 heterostructure is prepared by (i) coating WS2 paste on the carbon cloth substrate, (ii) drying the coated cloth substrate at 200°C for 1 hour under the inert atmosphere, and (iii) layering the coated carbon cloth substrate with the WSe2 paste and heating at 200°C to get the WS2/WSe2 heterostructure.
[0009] In some embodiments, the WS₂ is synthesized by (i) mixing tungstic acid and thiourea in a molar ratio of 1:48 to obtain a first mixture, and (ii) heating the first mixture at 600°C for 3 hours under N₂ atmosphere.
[0010] In some embodiments, the WSe₂ is synthesized by (i) mixing tungstic acid and dibenzyl diselenide in a molar ratio of 1:2 to obtain a second mixture, and (ii) heating the second mixture at 600°C for 3 hours under the N₂ atmosphere.
[0011] In some embodiments, the Ru-doped WS₂ is synthesized by (i) mixing 0.8 mmol of tungstic acid, 0.2 mmol of ruthenium (III) acetylacetonate, and 48 molarity of thiourea in a molar ratio of 1:48 to obtain a third mixture, and (ii) heating the third mixture at 600°C for 3 hours under the N₂ atmosphere.
[0012] The present invention offers significant advantages by addressing the major challenges faced by existing electrolysis technologies, including high cost, limited availability, and poor catalytic activity. Through the introduction of a novel green electrolysis approach, this invention provides a sustainable and efficient method for hydrogen production. The development of transition metal dichalcogenides (TMDCs)-based heterostructures as electrocatalysts represents a new frontier in future energy solutions, particularly for hydrogen generation. This method enables the production of high-performance electrocatalysts at a significantly lower cost compared to traditional precious-metal-based catalysts, such as platinum (Pt), while demonstrating superior hydrogen evolution reaction (HER) activity. The TMDC heterostructures feature enhanced electron transfer efficiency, abundant active sites, and faster charge transfer kinetics. Moreover, the fabricated TMDC heterostructures, particularly WSe2/Ru-WS2/CC, exhibit long-lasting durability and stability in harsh electrochemical environments, making them highly reliable for extended use. The green electrolysis approach further promotes environmentally friendly hydrogen production, contributing to cleaner and renewable energy solutions. Notably, the performance of these novel TMDC heterostructures is comparable to or exceeds that of platinum, setting a new benchmark for electrocatalytic excellence in hydrogen energy applications.
[0013] These and other aspects of the embodiments herein will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. It should be understood, however, that the following descriptions, while indicating preferred embodiments and numerous specific details thereof, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the embodiments herein without departing from the spirit thereof, and the embodiments herein include all such modifications.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The embodiments herein will be better understood from the following detailed description with reference to the drawings, in which:
[0015] FIG.1 is a flow diagram that illustrates a method for preparing transition metal dichalcogenides (TMDCs)-based heterostructure electrocatalysts for efficient hydrogen production according to some embodiments herein;
[0016] FIG.2 depicts an exemplary furnace setup used for synthesizing the transition metal dichalcogenides (TMDCs) including WS₂, WSe₂, and Ru-doped WS₂ according to some embodiments herein;
[0017] FIGS.3A-B shows the structural characteristics of the prepared WS2, WSe2 and Ru-WS2 samples according to some embodiments herein;
[0018] FIGS. 4A-D depicts the high-resolution XPS core level spectra of W-4f, S-2p, Se-3d and Ru-3d states of the WS2, WSe2 and Ru-WS2 samples according to some embodiments herein;
[0019] FIGS.5A-C depicts the comparative polarization curves and Tafel slopes of WS2/CC, WSe2/CC, Ru-WS2/CC, and the heterostructures WSe2/WS2/CC, WSe2/ Ru-WS2/CC along with standard Pt/C electrocatalyst samples according to some embodiments herein;
[0020] FIGS. 6A-B depicts charge transfer resistance from the EIS and durability measurements of the WSe2/Ru-WS2/CC heterostructure electrocatalyst samples according to some embodiments herein; and
[0021] FIGS. 7A-B depicts simulated band structures of the WSe2/WS2/CC and WSe2/Ru-WS2/CC heterostructures according to some embodiments herein.
DETAILED DESCRIPTION OF THE DRAWINGS
[0022] The embodiments herein and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments that are illustrated in the accompanying drawings and detailed in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
[0023] As mentioned, there remains a need to address the aforementioned technical drawbacks in existing technologies for a method for efficient and scalable fabrication of transition metal dichalcogenide (TMDC)-based heterostructures. The fabricated TMDC heterostructures, particularly WSe₂/Ru-WS₂/CC, exhibit long-lasting durability and stability in harsh electrochemical environments, making them highly reliable for extended use. The green electrolysis approach further promotes environmentally friendly hydrogen production, contributing to cleaner and renewable energy solutions. Referring now to the drawings, and more particularly to FIGS. 1 through 7, where similar reference characters denote corresponding features consistently throughout the figures, preferred embodiments are shown.
[0024] FIG.1 is a flow diagram that illustrates a method for preparing transition metal dichalcogenides (TMDCs)-based heterostructure electrocatalysts for efficient hydrogen production according to some embodiments herein. At step 102, the method includes, synthesizing transition metal dichalcogenides (TMDCs) including WS₂, WSe₂, and Ru-doped WS₂. At step 104, the method includes coating on carbon cloth substrate with the synthesized transition metal dichalcogenides (TMDCs) by applying one of the transition metal dichalcogenides (TMDCs) including WS₂, WSe₂, and Ru-doped WS₂ onto the carbon cloth substrate. At step 106, the method includes drying the carbon cloth substrate coated with the prepared transition metal dichalcogenides (TMDCs) at 200°C for 1 hour under an inert atmosphere. At step 108, the method includes layering one of the synthesized transition metal dichalcogenides (TMDCs) including WS₂, WSe₂, and Ru-doped WS₂ on the coated carbon cloth and heating at 200°C to fabricate the TMDC-based heterostructures, the TMDC-based heterostructure is a Ru-WS2/WSe2 heterostructure or WS2/WSe2 heterostructure.
[0025] In an example embodiment, for transition metal dichalcogenides (TMDCs)-based heterostructure fabrication, a few drops of NMP solution were added to 2 mg of prepared sample (i.e.) WS2, WSe2 and Ru-WS2 and it was ground with agate mortar until a homogeneous paste is obtained. Then the paste was coated on 1x1 cm2 carbon cloth (CC) substrate using the doctor blade technique. The Ru-WS2 paste was coated on the CC substrate and dried at ambient conditions for one hour. Then the second layer of WSe2 was coated on top of the Ru-WS2 layer. The coated heterostructure on CC was heated at 200 ℃ for 1 hour under the N2 atmosphere to enhance contact between layers and form stable heterostructures. Similarly, the WS2 and WSe2 heterostructure is prepared by coating a paste of WS2 on 1x1 cm2 carbon cloth substrate using the doctor blade technique and dried at ambient conditions for one hour. Then the second layer of WSe2 was coated on the WS2 layer. The coated heterostructure on CC was heated at 200 ℃ for 1 hour under the N2 atmosphere to enhance contact between layers and form stable heterostructures. The fabricated WS2/WSe2 and Ru-WS2/WSe2 heterostructure were subjected to the electrochemical Hydrogen Evolution Reaction (HER) measurement in 1M KOH electrolyte for H2 generation. The heterostructure catalyst showed a higher performance by releasing the H2 gas in the form of bubbles through water dissociation.
[0026] FIG.2 depicts an exemplary furnace setup used for synthesizing transition metal dichalcogenides (TMDCs) including WS₂, WSe₂, and Ru-doped WS₂ according to some embodiments herein. WS₂ including a mixture of tungstic acid and thiourea in a molar ratio of 1:48, WSe₂ including a mixture of tungstic acid and dibenzyl diselenide in a molar ratio of 1:2, Ru-doped WS₂ including a mixture of 0.8 mmol of tungstic acid, 0.2 mmol of ruthenium (III) acetylacetonate, and 48 molarity of thiourea in a molar ratio of 1:48 are heated at 600°C for 3 hours under N₂ atmosphere to obtain the WS₂, WSe₂, and Ru-doped WS₂ (Ru-WS2) transition metal dichalcogenides respectively as black-colored product which is collected after the furnace temperature stabilizes to ambient conditions, without undergoing post-cleaning treatment.
[0027] FIGS.3A-B shows the structural characteristics of the prepared WS2, WSe2 and Ru-WS2 samples according to some embodiments herein. The XRD pattern (Fig.2 (A)) reveals that the WS2, WSe2, and Ru-WS2 exhibit typical 2H-hexagonal crystal structure and their crystal indices were well existed with JCPDS card numbers, 01-084-1395 for WS2 and Ru-WS2 and 01-071-0600 for WSe2. It is observed that the (002) peak intensity in the Ru-WS2 sample was suppressed indicating the strain developed into the crystal lattice. Moreover, no impurity peaks identified in the XRD pattern qualitatively suggest the formation of pure WS2, WSe2, and Ru-WS2 crystal phases. The Raman spectra of all samples are presented in Fig. 2 (B). The typical in-plane (𝐸l2𝑔) and out-of-plane (A1g) phonon vibrational modes were ascribed at 330 and 425 cm-1 for WS2 and Ru-WS2. Whereas for WSe2 the characteristic peaks were observed at 256.7 and 264 cm-1. The identification of these Raman bands indicates the 2H crystal structure of WS2, WSe2, and Ru-WS2.
[0028] FIGS. 4A-D depicts the high-resolution XPS core level spectra of W-4f, S-2p, Se-3d and Ru-3d states of the WS2, WSe2 and Ru-WS2 samples according to some embodiments herein. From Fig.4 (A), the W4+ oxidation peaks of WS2 observed at binding energies of 33, 35 and 38.5 eV belong to 4f 5/2, 4f 3/2 and 5p 1/2 spin orbital states. The S-2p core level spectra (Fig. 3 (B)) of the WS2 sample deconvoluted into two peaks at binding energies of 162.6 and 163.8 eV, corresponding to 2p3/2 and 2p1/2 states, respectively. The XPS spectra of W-4f of WSe2 and Ru-WS2 shows a major change, where the W6+ oxidation state is detected due to surface oxidation. For WSe2, the binding energies of the peaks 4f7/2 and 4f5/2 are located at 32.2 and 34.2 eV corresponding to W4+ oxidation. Whereas, the peaks at binding energies 35.8 and 38 eV represent W6+ oxidation. The XPS core level spectra of Ru-WS2 in the regions W-4f and S-2p have significant variation due to doping. In W-4f state, the peaks 4f7/2 and 4f5/2 were detected at the binding energies of 32 and 34.7 eV attributed to W4+ oxidation. The W6+ oxidation state was displayed at the binding energies of 35.2 and 37.2 eV. whereas, in S-2p (Fig.3(B)) spectra, the 2p3/2 and 2p1/2 peaks were observed at the binding energies 161.5 and 162.9 eV respectively. It is observed that the deconvoluted peaks in W-4f and S-2p of Ru-WS2 were shifted towards the lower binding energy. This shifting resulted in the electron's cloud density increasing due to the doping of Ru. Figure 3 (C) shows the XPS spectra of Se-3d state, in which the 3d5/2 and 3d3/2 were located at the binding energies 34.8 and 35.8 eV respectively. The XPS core-level spectra of the dopant Ru-3d state (Fig. 3(D)) show two major peaks corresponding to 3d5/2 and 3d3/2 signals that are deconvoluted with the Ru4+ and Ru5+ oxidation states. The determined binding energies of Ru4+ oxidation state to be 280.4 and 283.7 eV and for Ru5+ oxidation state the binding energies are 281.3 and 285.4 eV. The C1s chemical state is clearly identified in the sample, as the binding energy (284.6eV) of the C-C signal is close to the Ru-3d3/2 state.
[0029] FIGS.5A-C depicts the comparative polarization curves and Tafel slopes of WS2/CC, WSe2/CC, Ru-WS2/CC, and the heterostructures WSe2/WS2/CC, WSe2/Ru-WS2/CC along with standard Pt/C electrocatalyst samples according to some embodiments herein. As shown in Fig.5 (A), the bare CC electrocatalyst shows poor catalytic activity as compared with pure and heterostructure catalysts. In contrast, the coated samples exhibit superior performance and draw cathode current density up to 100 mA cm-2. The on-set potentials of the catalyst measured to be 587, 200, 84, 15, 9, 7, and 5 mV for WS2/CC, WSe2/CC, Ru-WS2/CC, WSe2/WS2/CC, Pt/C and WSe2/Ru-WS2/CC respectively. The overpotentials at standard 10 mA cm-2 current density are measured at 476, 366, 168, 86, 52, and 47 mV for WS2/CC, WSe2/CC, Ru-WS2/CC, WSe2/WS2/CC, Pt/C and WSe2/Ru-WS2/CC, respectively. As observed, the heterostructure catalysts (WSe2/WS2/CC, WSe2/Ru-WS2/CC) show excellent HER performance. From Fig. 5B, it is observed that the WSe2/Ru-WS2/CC catalyst exhibits efficient catalytic activity over the commercial Pt/C electrocatalyst. The Tafel slopes (Fig.5 (C)) were calculated using ɳ = alogb straight line relation, where ɳ stands for overpotential, a is Tafel slope and b is constant. The Tafel slopes are measured to be 173,165, 169,73 mV dec-1 for bare CC, WS2/CC, WSe2/CC and Ru-WS2/CC electrocatalysts. Whereas the Tafel slope for heterostructures WSe2/WS2/CC, Pt/C and WSe2/Ru-WS2/CC were measured to be 44, 30 and 25 mV dec-1 respectively. It has been concluded that the heterostructure Ru-WS2/WSe2/CC is highly active to produce hydrogen and making them as attractive material over Pt/C.
[0030] FIGS. 6A-B depicts charge transfer resistance from the EIS and durability measurements of the WSe2/Ru-WS2/CC heterostructure electrocatalyst samples according to some embodiments herein. The EIS profile of WSe2/Ru-WS2/CC heterostructure electrocatalyst with Randles circuit is shown in Fig.6 (A). After fitting the EIS spectra with equivalent circuit diagram, the charge transfer resistance (Rct) of WSe2/Ru-WS2/CC heterostructure catalyst calculated to be 26 Ω. The ultra-small Rct indicate that the catalyst exhibits excellent active sites by its inherent interfacial contact and recombination of electrons and holes cloud density. The durability test of WSe2/Ru-WS2/CC was performed at 200 mV vs RHE in 1M KOH electrolyte and presented in Fig.4(B). The hetero-structured catalyst shows stable current density for 10 hours.
[0031] FIGS. 7A-B depicts simulated band structures of the WSe2/WS2/CC and WSe2/Ru-WS2/CC heterostructures according to some embodiments herein. The electron transfer characteristics in the WSe2/WS2/CC and WSe2/Ru-WS2/CC heterostructure is analyzed from the band structure developed using numerical simulations with 1D SCAPS software. It is clearly observed that, the catalysts possess the staggered gap (type-II) semiconductor heterojunction. The observed band alignment is beneficial for promoting electrons and holes transfer and separate the charge carriers at the interface. Moreover, the position of quasi-Fermi levels observed in WS2 and Ru-WS2 confirms the n-type conductivity, whereas WSe2 shows p-type behavior. From Fig. 7(A), it is noticed that the Fermi level is aligned close to the conduction band but for WSe2/Ru-WS2/CC, it was located inside the conduction band revealing the typical degenerate n-type semiconductor. Degenerate semiconductors, with a high charge density of approximately 10²¹ cm⁻³ due to free electron-hole plasma, are beneficial for creating interfacial charge density, which in turn enhances the hydrogen evolution reaction (HER) activity. Therefore, from the experimental and simulation results, it is concluded that the 2D TMDCs heterostructures are competent electrocatalysts for commercially Pt/C and produce efficient hydrogen evolution.
[0032] The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the appended claims.

, Claims:I/We claim:

1. A method for preparing transition metal dichalcogenides (TMDCs)-based heterostructure electrocatalysts for efficient hydrogen production, wherein the method comprises,
synthesizing transition metal dichalcogenides (TMDCs) comprising WS₂, WSe₂, and Ru-doped WS₂ using a solid state reaction technique;
coating a carbon cloth substrate (CC) with the synthesized transition metal dichalcogenides (TMDCs) by applying one of the transition metal dichalcogenides (TMDCs) comprising WS₂, WSe₂, and Ru-doped WS₂, onto the carbon cloth substrate and drying under controlled conditions,
wherein the synthesized transition metal dichalcogenides (TMDCs) are mixed with N-methylpyrrolidone (NMP) to form a homogeneous paste for applying on the carbon cloth substrate;
drying the carbon cloth substrate coated with one of the synthesized transition metal dichalcogenides (TMDCs) at 200°c for 1 hour under an inert atmosphere; and
layering one of the synthesized transition metal dichalcogenides (TMDCs) comprising WS₂, WSe₂, and Ru-doped WS₂ on the coated carbon cloth and heating at 200°C to prepare the TMDC-based heterostructures, wherein the TMDC-based heterostructure is a Ru-WS2/WSe2 heterostructure or WS2/WSe2 heterostructure.

2. The method as claimed in claim 1, wherein the Ru-WS2/WSe2 heterostructure is prepared by (i) coating the Ru-WS2 paste on the carbon cloth substrate, (ii) drying the coated cloth substrate at 200°C for 1 hour under the inert atmosphere, and (iii) layering the coated carbon cloth substrate with the WSe2 paste, and heating at 200°C to get the Ru-WS2/WSe2 heterostructure.

3. The method as claimed in claim 1, wherein the WS2/WSe2 heterostructure is prepared by (i) coating WS2 paste on the carbon cloth substrate, (ii) drying the coated cloth substrate at 200°C for 1 hour under the inert atmosphere, and (iii) layering the coated carbon cloth substrate with the WSe2 paste and heating at 200°C to get the WS2/WSe2 heterostructure.

4. The method as claimed in claim 1, wherein the WS₂ is synthesized by (i) mixing tungstic acid and thiourea in a molar ratio of 1:48 to obtain a first mixture, and (ii) heating the first mixture at 600°C for 3 hours under N₂ atmosphere.

5. The method as claimed in claim 1, wherein the WSe₂ is synthesized by (i) mixing tungstic acid and dibenzyl diselenide in a molar ratio of 1:2 to obtain a second mixture, and (ii) heating the second mixture at 600°C for 3 hours under the N₂ atmosphere.

6. The method as claimed in claim 1, wherein the Ru-doped WS₂ is synthesized by (i) mixing 0.8 mmol of tungstic acid, 0.2 mmol of ruthenium (III) acetylacetonate, and 48 molarity of thiourea in a molar ratio of 1:48 to obtain a third mixture, and (ii) heating the third mixture at 600°C for 3 hours under the N₂ atmosphere.

Dated this November 11, 2024

Arjun Karthik Bala
(IN/PA 1021)
Agent for Applicant

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