Integrated 3D self-supported Ni decorated MoO2 nanowires as highly efficient electrocatalysts for ultra-highly stable and large-current-density hydrogen evolution

Abstract

The design and development of non-noble metal electrocatalysts for the hydrogen evolution reaction (HER) is highly desirable, but still cannot satisfy actual requirements in terms of superior activity, ultrahigh stability and ability to carry large current densities. In this study, Ni nanoparticles anchored onto MoO₂ nanowires have been synthesized on carbon cloth via in situ exsolution under a reducing atmosphere. Impressively, the obtained Ni–MoO₂-450 NWs/CC exhibits an excellent platinum-like HER activity with a nearly zero onset overpotential and a small Tafel slope of ∼30 mV dec⁻¹, which implies that the fast recombination step is rate-limiting. Surprisingly, our sample gives an unprecedented stable catalytic activity over 320 hours in 1 M KOH, and can retain its activity at large current densities, even in the order of 1000 mA cm⁻², which is far better than other reported catalysts. Such an outstanding performance should be mainly attributed to the integrated 3D self-supported nanocatalyst, the high electronic conductivity framework and the synergistic coupling effect between Ni and MoO₂ interfaces. This work may thus provide an insight into the design and fabrication of alternative catalysts to Pt-based catalysts for the HER.