An interface engineering strategy of MoS2/perovskite oxide as a bifunctional catalyst to boost overall water splitting

Abstract

In this paper, a La_0.6Sr_0.4CoO₃/MoS₂ composite electrocatalyst was prepared by a sol–gel method and subsequent dry ball milling. It showed high activity and favored the reaction kinetics for the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) under alkaline conditions. When applied for overall water splitting, it showed a low full-cell voltage of 1.48 V at 10 mA cm⁻² that is comparable to state-of-the-art noble metal catalysts. Using in situ Raman spectroscopy we identified the surface reactive intermediates: cobalt (hydr)oxides with high oxidation states were formed under anodic potentials at the La_0.6Sr_0.4CoO₃/MoS₂ interface to facilitate the OER. DFT calculations showed that the two-phase interface facilitated the polarization of the interface charge and modulated the bonding of the reaction intermediates, accelerating the overall water splitting. This work exemplifies the impact of interfacial engineering on the electrocatalytic performance and provides a new route for the development of low-cost and non-noble metal catalysts for water electrolysis.