Bifunctional Noble Metal-free Ternary Chalcogenide Electrocatalysts for Overall Water Splitting

Shantanu Singh; Ahamed Irshad; Germany Diaz De la Cruz; Boyang Zhao; Billal Zayat; Qiaowan Chang; Sri Narayan; Jayakanth Ravichandran

arXiv · 2405.14187

Bifunctional Noble Metal-free Ternary Chalcogenide Electrocatalysts for Overall Water Splitting

Shantanu Singh·Ahamed Irshad·Germany Diaz De la Cruz·Boyang Zhao·Billal Zayat·Qiaowan Chang·Sri Narayan·Jayakanth Ravichandran

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Abstract

Hydrogen has been identified as a clean, zero carbon, sustainable, and promising energy source for the future, and electrochemical water splitting for hydrogen production is an emission-free, efficient energy conversion technology. A major limitation of this approach is the unavailability of efficient, abundant, inexpensive catalysts, which prompts the need for new catalytic materials. Here, we report the synthesis and electrocatalytic properties of a novel transition metal-based ternary chalcogenide family, LaMS$_3$ (M = Mn, Fe, Co, Ni). Powder X-ray diffraction confirms the phase purity of these materials, while composition analysis using energy dispersive spectroscopy (EDS) confirms the presence of the stoichiometric ratio of elements in these compounds. X-ray photoelectron spectroscopy (XPS) and X-ray absorption spectroscopy (XAS) were used to study the chemical states on the surface and in bulk, respectively. These materials exhibit bifunctional catalytic activity towards the two half-reactions of the water-splitting process, with LaNiS$_3$ being the most active material for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). The LaMS$_3$ compounds show long-term stability with negligible change in the overpotential at a constant current density of 10 mA cm$^{-2}$ over 18 hours of measurements. As compared to the corresponding ternary oxides, the LaMS$_3$ materials exhibit higher activity and significantly lower Tafel slopes. The ability to catalyze both half-reactions of water electrolysis makes these materials promising candidates for bifunctional catalysts and presents a new avenue to search for high-efficiency electrocatalysts for water splitting.

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Shantanu Singh, Ahamed Irshad, Germany Diaz De la Cruz, Boyang Zhao, Billal Zayat, Qiaowan Chang, Sri Narayan, Jayakanth Ravichandran. 2024-05-23. Bifunctional Noble Metal-free Ternary Chalcogenide Electrocatalysts for Overall Water Splitting. https://arxiv.org/abs/2405.14187

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