Nickel-decorated RuO2 nanocrystals with rich oxygen vacancies for high-efficiency overall water splitting.

Abstract

Designing transition metal-oxide-based bifunctional electrocatalysts with excellent activity and stability for OER/HER to achieve efficient water splitting is of great importance for renewable energy technologies. Herein, a highly efficient bifunctional catalysts with oxygen-rich vacancies of nickel-decorated RuO2 (NiRuO2-x) prepared by a unique one-pot glucose-blowing approach were investigated. Remarkably, the NiRuO2-x catalysts exhibited excellent HER and OER activity at 10mAcm-2 in alkaline solution with only a minimum overpotential of 51mV and 245mV, respectively. Furthermore, the NiRuO2-x overall water splitting exhibited an ultra-low voltage of 1.6V to obtain 10mAcm-2 and stability for more than 10h. XPS measurement and theoretical calculations demonstrated that the introduction of Ni-dopant and oxygen vacancies make the d-band center to lie close to the Fermi energy level, the chemical bonds between the active site and the adsorbed oxygen intermediate state are enhanced, thereby lowering the reaction activation barriers of HER and OER. The assembly of solar-driven alkaline electrolyzers facilitate the application of the NiRuO2-x bifunctional catalysts.