Three-dimensional Core@Shell Co@CoMoO4 nanowire arrays as efficient alkaline hydrogen evolution electro-catalysts.

Graphical abstract Highlights • Tailoring Co/CoMoO4 interface is achieved by hydrogenation treatment of core@shell cobalt carbonate hydroxide@CoMoO4. • Core@shell Co@CoMoO4 nanowires exhibit superior HER performance, quite closing to that of commercial PtC in 1.0 M KOH. • Synergistic effect between Co and CoMoO4 is responsible for the magnificent activity enhancement. Abstract Tailoring efficient and stable electrocatalysts based on non-noble metal elements for hydrogen evolution reaction (HER) is highly imperative for the commercialization of water splitting electrolysors. Herein, a self-standing core@shell Co@CoMoO 4 nanowire array (Co@CoMoO 4 NA) electrode is developed by calcination of a cobalt carbonate hydroxide@CoMoO 4 (CCH NA@CoMoO 4) precursor under H 2 /N 2 atmosphere. In this way, synergistic Co/CoMoO 4 heterostructure interfaces and 3D porous electrode architecture are built up, which are proved to be reliable strategies for HER catalytic activity enhancement. In 1.0 M KOH solution, Co@CoMoO 4 NA electrode exhibits an impressive activity with an extremely low overpotential of 46 mV at 10 mA cm−2, quite closing to that of commercial PtC (31 mV at 10 mA cm−2). These findings may inspire the exploration of new electro-catalysts for efficient HER by modulating multiple components interfaces. [ABSTRACT FROM AUTHOR]