Alternate to Molybdenum Disulfide: A 2D, Few-Layer Transition-Metal Thiophosphate and Its Hydrogen Evolution Reaction Activity over a Wide pH Range

• Published in: ChemElectroChem Vol. 3; no. 9; pp. 1392 - 1399
• Main Authors: Jenjeti, Ramesh Naidu, Austeria, Muthu P., Sampath, Srinivasan
• Format: Journal Article
• Language: English
• Published: Weinheim Blackwell Publishing Ltd 01.09.2016; John Wiley & Sons, Inc
• Subjects: adsorption; Catalysts; Current density; Exchange; Hydrogen; Hydrogen evolution; Molybdenum disulfide; nanosheets; Nickel; semiconductors; Tafel slopes
• ISSN: 2196-0216; 2196-0216
• DOI: 10.1002/celc.201600235

A two‐dimensional, few‐layer nickel thiophosphate, NiPS3, was introduced as a hydrogen evolution reaction catalyst from aqueous acidic, alkaline, and neutral solutions. NiPS3 is semiconducting in nature, and its band structure calculations revealed the importance of the [P2S6]4− units in the adsorption of hydrogen and subsequent evolution. Onset potentials of −0.062, −0.065, and −0.298 V versus RHE were observed in acidic, alkaline, and neutral media. Tafel slopes of 55, 48, and 94 mV dec−1 and exchange current densities of 1.8×10−4, 6.1×10−4, and 3.2×10−5 A cm−2 were observed in aqueous 0.5 m H2SO4, 1 m KOH, and 3.5 % NaCl solutions, respectively. The catalyst was found to be very stable, and the constituting elements are earth abundant. The present study opens up a new class of semiconducting layered materials to catalyze various redox reactions. Achieving a single layer will be of great interest to electrical and magnetic devices. Put on a few layers: A ternary phosphochalcogenide based on earth‐abundant elements, NiPS3, is found to be a very good electrocatalyst for hydrogen evolution from acidic, alkaline, and 3.5 % NaCl solutions.