Potential Dependent Electrochemical Exfoliation of NiPS₃ and Implications for Hydrogen Evolution Reaction

Transition-metal thiophosphites are an emerging group of 2D layered materials. Their application potential spans from electrocatalysis to optoelectronics and energy storage. In this study, we investigated the degree of exfoliation dependence on the exfoliation potential. For this purpose, we used the intercalation of large tetra-butylammonium hexafluorophosphate (TBAPF6) in dry acetonitrile. The exfoliation was carried out using potentials ranging from −2.8 to −3 V vs Ag/Ag+ reference electrode in an inert atmosphere of a glovebox. In addition to that, we also tested the application of voltage pulses at a more negative potential (−3.8 V). The results show that the degree of exfoliation is strongly dependent on the potential used with more negative potentials yielding higher degrees of exfoliation. This resulted in an enhancement of hydrogen evolution reaction (HER) performance in alkaline media. These results show that a simple method can be used to easily prepare highly active electrocatalysts with high application potential.