Reconstruction Co-O-Mo in amorphous-crystalline MoOx/Co(OH)2 interface for industry-level active and stable electrocatalytic seawater hydrogen evolution

Abstract

The activity of molybdenum (Mo)-based catalysts is significantly limited by the dissolution of Mo under alkaline conditions. Herein, using the dissolution of Mo in electrolysis, we firstly developed a feasible method to prepare an amorphous-crystalline MoOx/Co(OH)2 interfacial electrocatalysts with high activity and corrosion resistance on nickel foam (MoOx/Co(OH)2/NF). Notably, the dissolution of Mo accelerated the self-reconstruction process to favorably generate highly active and stable Co-O-Mo6+ species. Among them, high-valence Mo6+ in Co-O-Mo species can accumulate a large number of electrons at the O sites, thus optimizing p-band center of O sites and enhance the hydrogen adsorption ability (ΔGH* = 0.05 eV). Meanwhile, in-situ formed MoO42- and Co(OH)2 in MoOx/Co(OH)2/NF could inhibit the damage of metals ions and Cl- to O active species, and thereby enhancing its stability in electrocatalytic seawater splitting. As expected, the catalyst displayed a superior activity with ultralow overpotentials (HER: 215 mV @ 1000 mA·cm −2) and high stability for 1000 h at 500 mA·cm−2 in alkaline seawater electrolytes. In all, this study can provide a new route to prepare highly-active and corrosion-resistant electrocatalysts via self-reconstruction, and further the development of industrial hydrogen production.