Single Ru atoms dispersed on MoSe₂/MXene nanosheets with multiple interfaces for enhanced acidic hydrogen evolution

Exposing more catalytic active sites is an effective strategy to enhance the catalyst activity for hydrogen evolution reaction (HER). Herein, Ti₃C₂T_x MXene served as a substrate to load thin and curved 2H–MoSe₂ nanosheets by a typical hydrothermal method, forming MoSe₂/MXene heterointerface with the fully exposed Mo edge sites. And then, atomically dispersed Ru single atoms (RuSAs) were successfully anchored on the MoSe₂/MXene (RuSAs@MoSe₂-MXene). The X-ray absorption near edge structure (XANES) demonstrates that Ru is loaded as single atoms on MoSe₂ and MXene. The prepared sample exhibits improved catalytic activity with a small overpotential of 49 mV at 10 mA cm⁻² and a low Tafel slope of 52 mV dec⁻¹ for HER in 0.5 M H₂SO₄. It also exhibits excellent stability with a small attenuation voltage of 10 mV for 120 h at 10 mA cm⁻² in 0.5 M H₂SO₄. When assembled into a two-electrode system of RuSAs@MoSe₂-MXene||RuO₂, it only requires a relatively low potential of 1.626 V at 10 mA cm⁻² to drive overall water splitting (OWS). Control experiments disclose the highly improved performance can be primarily attributed to the introduced RuSAs and MoSe₂/MXene heterointerfaces exposing more active sites of Ru and Mo. Moreover, the high conductivity of MXene can increase charge transfer in HER process. The interface engineering with multiple interfaces can provide fresh impetus for the development of efficient HER catalysts.