Pseudo-Periodically Coupling NiO Lattice with CeO Lattice in Ultrathin Heteronanowire Arrays for Efficient Water Oxidation.

Abstract

Transition metal oxides (TMOs) have been under the spotlight as promising precatalysts for electrochemical oxygen evolution reaction (OER) in alkaline media. However, the slow and incomplete self-reconstruction from TMOs to (oxy)hydroxides as well as the formed (oxy)hydroxides with unmodified electronic structure gives rise to the inferior OER performance to the noble metal oxide ones. Herein, a unique dual metal oxides lattice coupling strategy is proposed to fabricate carbon cloth-supported ultrathin nanowires arrays, which are composed of pseudo-periodically welded NiO with CeO2 nanocrystals (NiO/CeO2 NW@CC). When served as an OER precatalyst in 1.0 m KOH, the NiO/CeO2 NW@CC shows an ultralow overpotential of 330mV at 50mA cm-2 , along with an impressive cycle durability of more than 3 days even at 50mA cm-2 , surpassing CC-supported NiO and commercial IrO2 catalysts. The combined experimental and theoretical investigations unveil that the atomic coupling of CeO2 can not only appreciably trigger the generation of oxygen vacancies and expedite phase transformation of NiO into active NiOOH, but also in situ create a chemical bond with the formed NiOOH and enable the electron injection, thus effectively inhibiting the aggregation of the accessible NiOOH nanodomains and optimizing their reaction free energy towards oxygen-containing intermediates.