Co3 O4 @Cu-Based Conductive Metal-Organic Framework Core-Shell Nanowire Electrocatalysts Enable Efficient Low-Overall-Potential Water Splitting.

In the work reported herein, the electrocatalytic properties of Co3 O4 in hydrogen and oxygen evolution reactions have been significantly enhanced by coating a shell layer of a copper-based metal-organic framework on Co3 O4 porous nanowire arrays and using the products as high-performance bifunctional electrocatalysts for overall water splitting. The coating of the copper-based metal-organic framework resulted in the hybridization of the copper-embedded protective carbon shell layer with Co3 O4 to create a strong Cu-O-Co bonding interaction for efficient hydrogen adsorption. The hybridization also led to electronically induced oxygen defects and nitrogen doping to effectively enhance the electrical conductivity of Co3 O4 . The optimal as-prepared core-shell hybrid material displayed excellent overall-water-splitting catalytic activity that required overall voltages of 1.45 and 1.57 V to reach onset and a current density of 10 mA cm-2 , respectively. This is the first report to highlight the relevance of hybridizing MOF-based co-catalysts to boost the electrocatalytic performance of nonprecious transition-metal oxides.