Regulation of crystallinity and defects on CoNiRuOx nanocages for enhanced oxygen evolution reaction

Abstract

Amorphous/crystalline (a/c) metal-oxide nanocages with defects are promising materials towards the realization of efficient water electrocatalysis. In this work, we not only constructed a Ru doping porous nanocages (PNCs) structure, but also studied the relationship between both crystallinity of a/c degrees and oxygen vacancy (Ovac) levels in a/c CoNiRuOx PNCs catalysts and their catalytic properties. Owing to the rich mass transfer channels, optimized crystallinity and Ovac levels, and efficient catalytic model of “Ni-O-Co-O-Ru-O-Ni” for well-distributed electron density, the optimized CoNiRuOx-2 PNCs exhibited the alkaline oxygen evolution reaction (OER) properties with an overpotential of 245 mV at 10 mA cm−2 and remarkable stability for 60 h, surpassing other series of a/c CoNiRuOx and benchmark RuO2 catalysts. In addition, the electrode couple a/c CoNiRuOx-2//Pt/C only need an ultralow voltage of 1.54 V to drive overall water splitting. This work proposed the introduction and quantitative control on both a/c heterostructure degree and Ovac level, offering guidelines for OER catalysis.