Synchronized redox pairs in metal oxide/hydroxide chemical analogues for an efficient oxygen evolution reaction.

A two-step electrodeposition of CoMn 2 O 4 and its chemical analogue CoMn(OH) x directly over Ni-foam yields an excellent water oxidation overpotential of 260 mA cm -2 with a Tafel slope of 29 mV dec -1 and a four-fold increase in turnover frequency. The enhanced efficacy of the composite catalyst is realized through synchronized redox pairs and superior carrier transport.