Electronic coupling regulation in yolk-shell nanostructured nickel-cobalt diselenides with octahedral coordination for boosted oxygen evolution reaction

It is fairly desired but remains challenging to synthesize metal selenides with nanosized building blocks via simplified approaches which make more active sites exposed to electrolytes for achieving high-efficient electrocatalysts for oxygen evolution reaction (OER). Herein, on the basis of the Kirkendall effect, we developed a simple synthesis of yolk-shell nanostructured nickel-cobalt diselenides (NiCoSe2) with nanosized wide annular aisles via one-step electrodeposition. Expressly, the electronic coupling between Ni and Co cations was well regulated via the optimization of Ni/Co atomic ratios to regulate eg filling of Ni for optimized OER. The elaborate yolk-shell nanostructured NiCoSe2 catalyst exhibits remarkable OER performance, delivering a low overpotential of 249 mV at a geometric current density of 10 mA cm−2 in alkaline media, a small Tafel slope of 43 mV dec−1 and a decent durability with a tiny decay of 23 mV over 20 h electrolysis. The Kirkendall effect-induced formation route of the yolk-shell nanostructure will provide helpful guidance for the rational design of hollow structured catalyst in the field of energy catalysis and other extended applications.