PO6 geometric configuration unit enhanced electrocatalytic performance of Co3O4 in acidic oxygen evolution

It is challenging to develop high-efficient and stable nonprecious metal-based electrocatalyst for oxygen evolution reaction (OER) in acid for proton exchange membrane (PEM) water splitting. Herein, P atoms were introduced into the lattice of spinel Co 3 O 4 (P-Co 3 O 4 ) to replace with octahedral coordinated Co 3+ via a hydrothermal process following a thermal treatment. The formation of PO 6 geometric configuration unit in Co 3 O 4 can trigger electron rearrangement around Co ions , which resulted in the high-active Co 2+ site on the surface, significantly decreasing the energy barrier of rate-determining step for OER. Moreover, the weaker covalency of the Co 3d-O 2p bond and higher formation energy of oxygen vacancy around Co 2+ in P-Co 3 O 4 inhibited the participation of lattice oxygen during OER process, enabling that P-Co 3 O 4 can work stably in acidic media. The obtained P-Co 3 O 4 afforded satisfying stability over 30 h in a PEM electrolysis device with an overpotential of 400 mV@10 mA/cm 2 in 0.1 M HClO 4 .