Researchers at the Center of Excellence for NaNo Energy & Catalysis Technology (CONNECT), Xiamen University in Malaysia, discovered that a noble metal-free electrocatalyst improves efficiency of hydrogen evolution from water. They have successfully developed a highly efficient water electrocatalyst called WS2/N-rGO/CC. During electrolysis, this advanced electrocatalyst delivers remarkable performance in the hydrogen evolution reaction (HER). This electrode reduces costs and maximizes hydrogen generation efficiency without expensive catalysts or additives. This discovery is considered to enhance electrochemical activity and will significantly contribute to the national initiatives of Malaysia.
Researchers at the Center of Excellence for NaNo Energy & Catalysis Technology (CONNECT), Xiamen University in Malaysia have developed a durable and efficient water electrocatalyst. It is made of a material called tungsten disulfide (WS2), which is a two-dimensional material with semiconducting properties. This material acts as an electron acceptor or donor in the process of electrolysis.
A highly advanced electrocatalyst, known as WS2/N-rGO/CC, is meticulously crafted on a carbon cloth (CC). This material combines the extraordinary properties of reduced graphene oxide (rGO) with the infusion of a minute amount of nitrogen (N). This results in a transformed reduced graphene oxide semiconductor, forming a two-dimensional lattice semiconductor.
Burning hydrogen gas as a fuel doesn’t cause global warming. However, most of the hydrogen gas today is made from fossil fuels, which do release greenhouse gases. To achieve carbon neutrality in the future, it’s important to generate hydrogen from clean sources like splitting water molecules with electricity. But the current methods are inefficient and limit the practical use of hydrogen-based technologies.
An improved electrocatalyst increases the efficiency of producing hydrogen gas through electrolysis. It achieves this by enhancing electrochemical activity, reaction surface area, and durability.
Through a hydrothermal reaction, the structure of two-dimensional WS2 can be transformed into nanoflowers, which are three-dimensional flower-like formations. These nanoflowers possess remarkable properties, including increased surface area for the electrocatalyst. As a result, they significantly enhance the efficiency of the reaction, leading to outstanding improvements in overall performance.
Lead author of the paper, Feng Ming Yap, said, “Synthesizing a self-supported electrode for the hydrogen evolution reaction in water hydrolysis is crucial because it addresses a fundamental challenge in clean energy production. Traditional methods often rely on expensive catalysts and supports, which can limit the efficiency and scalability of hydrogen production.”
He further added, “Our work represents a significant advancement by creating a self-supported electrode that not only enhances the electrocatalytic activity, but also offers a cost-effective and sustainable solution for hydrogen generation.” Feng Ming Yap is also a graduate student in the School of Energy and Chemical Engineering at Xiamen University Malaysia in Selangor Darul Ehsan, Malaysia.
WS2/N-rGO/CC is considered a self-supported electrode because it incorporates the active species of the electrocatalyst, tungsten disulfide, directly into the conductive materials. This eliminates the need for polymer binders or additives, which could mask the catalyst’s active sites or impede electron conductance. As a result, the reaction efficiency is maximized, leading to enhanced performance.
To determine the optimal concentration of dimethylformamide (DMF) for achieving the desired metallic 1T phase transition of WS2, the research team conducted experiments by incorporating different amounts of DMF into the final hydrothermal synthesis reaction.
The electrode made with a 50% DMF concentration in water showed better qualities compared to electrodes made with 0, 25, 75, and 100 percent DMF solutions. So, it is highly possible that the noble metal-free electrocatalyst improves efficiency of hydrogen evolution from water.
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Supervisor of the project and associate professor in the School of Energy and Chemical Engineering at Xiamen University Malaysia, Wee-Jun Ong, said, “Our electrode can efficiently produce hydrogen under a wide range of pH conditions, making it versatile and adaptable for various practical applications. It is a step towards sustainable and efficient hydrogen production, which is essential for a cleaner energy future.”
Most importantly, the electrocatalyst based on 50% WGC showed superior performance compared to the platinum benchmark electrocatalyst, which was 20% Pt-C/CC, for the HER in both acidic and basic conditions. Notably, the 50% WGC exhibited a significantly lower over potential, indicating a lower energy requirement for water splitting, compared to the 20% Pt-C/CC. Specifically, the over potential for the 50% WGC was measured at an impressive 21.13 mV, while the 20% Pt-C/CC had a higher over potential of 46.03 mV.
According to the research team, the importance of developing cost-effective and energy-efficient electrocatalysts, such as the 50% WGS, cannot be overstated in terms of realizing global clean energy objectives. This research is an integral part of Malaysia’s national initiatives, specifically the National Energy Transition Roadmap (NETR) and the Hydrogen Economy and Technology Roadmap (HETR). Its objective is to effectively contribute to Malaysia’s sustainable energy goals over the next five years.
“We aim to explore the scalability and practical implementation of our self-supported electrode technology. Our ultimate goal is to contribute to the transition to a sustainable energy landscape, where hydrogen can play a crucial role as a clean and renewable energy source,” said Ong.
Jian Yiing Loh, a researcher from Xiamen University Malaysia, played a vital role in the study conducted at the School of Energy and Chemical Engineering and the Center of Excellence for NaNo Energy & Catalysis Technology (CONNECT) in Selangor Darul Ehsan, Malaysia.
