Graphene-MoS2 vertically anchored on an MXene-derived accordion-like TiO2/C skeleton: an ultrastable HER catalyst

Abstract

As an alternative to Pt for the hydrogen evolution reaction (HER), MoS₂ has been widely studied and superior catalytic activity has been achieved. However, its electrochemical stability needs further improvement to satisfy industrial hydrogen production requirements. In this work, a hybrid of graphene-modified MoS₂ vertically anchored on an MXene-derived accordion-like TiO₂/C substrate (rGO-MoS₂/Acc-TiO₂/C) was fabricated for the first time. This synthetic catalyst shows an onset potential of 90 mV and a Tafel slope of 49.5 mV dec⁻¹. Most notably, it exhibits an ultrahigh cycling stability with negligible attenuation of catalytic activity after 150 000 CV cycles and 95% potential retention after 200 000 s of continuous galvanostatic measurements. Both experimental results and density functional theory simulations indicate that the high-stability TiO₂, vertically-grown MoS₂ and strong bonding between MoS₂ and TiO₂ synergistically boost the superior stability of rGO-MoS₂/Acc-TiO₂/C. This work provides an intriguing and effective approach to develop high-performance low-cost HER catalysts for hydrogen-production systems.