Selective Sulfuration of Two-Dimensional Nonlayered MoO2 Nanosheets for High-Current-Density Hydrogen Evolution

Triggering favorable synergistic effects in multicomponent catalysts is demonstrated to be an efficient route to design advanced high-performance HER electrodes, but it always requires sophisticated fabrication procedures to integrate and maintain optimal balance between different domains. 2D nonlayered materials are filled with surface dangling bonds, making their surface highly chemically active and enhancing their incorporation capability of the external functional components, which provide an ideal platform to design efficient multicomponent catalysts. In this work, as an initial proof of concept, ultrathin metallic 2D nonlayered MoO2 nanosheets were adopted as the infrastructure to mediate the incorporation of the active S component. The sulfuration process selectively occurred only on their coordinated-unsaturated surface sites without disturbing their internal structure, enabling us to efficiently optimize their surface hydrogen adsorption free energy while still preserving their high conductivity. The optimized S-MoO2 catalysts exhibited a Pt-comparable HER catalytic performance with a low overpotential of 356 mV at a current density of 1000 mA cm–2 in 0.5 M H2SO4 and outstanding stability under high current densities. Our results demonstrate a promising synthetic strategy to the multicomponent catalysts that may lead to the innovation of transformation and application of the 2D nonlayered materials.