Tailored Ce-Doped NiMoO4/MoS2@rGO Nanoarchitectures for Sustainable Electrochemical Water Splitting in Alkaline Medium

Abstract

In this study, we report a meticulously engineered electrocatalyst employing a multicomponent system consisting of Ce-doped NiMoO₄ nanorods as the primary component. The Ce-doped NiMoO₄ nanorods were primarily integrated with two-dimensional (2D) MoS₂ nanosheets and further modified with rGO, significantly enhancing the charge transport in the interfacial region of the hybrid nanoarchitecture (Ce-NiMoO₄/MoS₂@rGO). Cerium doping, combined with the multicomponent architecture, targeted toward enhancing the density of active sites and conductivity, which promoted efficient water decomposition. The synergistic effect of doping and heterostructure strategies resulted in efficient hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) performance of the Ce-NiMoO₄/MoS₂@rGO electrocatalyst. This electrocatalyst demonstrated impressive bifunctional activity with a low overpotential of 153 mV for the benchmark current of 10 mA cm^–2 and a Tafel slope of 82 mV dec^–1 for the HER. For the OER, an overpotential of 278 mV was observed for the cathodic current of 20 mA cm^–2 with a Tafel slope of 114 mV dec^–1. Additionally, our electrolyzer, utilizing Ce-NiMoO₄/MoS₂@rGO as electrodes, acquired a total current density of 10 mA cm^–2 at a full-cell voltage of 1.58 V. Moreover, the Ce-NiMoO₄/MoS₂@rGO heterostructure exhibited prolonged durability with minimal deactivation even after continuous operation for 24 h.