Cr doping and heterostructure-accelerated NiFe LDH reaction kinetics assist the MoS2 oxygen evolution reaction

Abstract

Although molybdenum disulfide (MoS₂) has garnered significant interest as a potential catalyst for the oxygen evolution reaction (OER), its poor intrinsic activity and few marginal active spots restrict its electrocatalytic activity. Herein, we successfully constructed a catalyst via a simple hydrothermal method by forming a heterostructure of MoS₂ with Cr-doped nickel–iron hydroxide (NiFe LDH) to synthesize a MoS₂/NiFeCr LDH catalyst to significantly improve the OER catalytic performance. MoS₂ plays a crucial function as an electron transport channel in the MoS₂/NiFeCr LDH heterostructure, which increases the electron transport rate. Furthermore, a larger active surface area for NiFeCr LDH is provided by the ultrathin layered structure of MoS₂, increasing the number of active sites and encouraging the OER. On the other hand, the introduction of Cr element increased the density of the catalytic center and provided additional Cr-OH active sites, which accelerated the oxygen decomposition reaction. These two factors act synergistically to improve the intrinsic structure of MoS₂, increase the number of reactive sites, and dramatically enhance the OER catalytic performance. Excellent OER activity is demonstrated by the MoS₂/NiFeCr LDH catalyst, which only needs an overpotential of 224 mV to obtain a current density of 10 mA cm⁻² and a Tafel slope of 61 mV dec⁻¹. The catalyst also demonstrated outstanding stability, with its activity practically holding steady after 48 h of testing. This work offers novel ideas for enhancing and designing MoS₂-based OER catalysts, and it provides a crucial reference for research in the field of clean energy.