Bimetallic cobalt-nickel coordination polymer electrocatalysts for enhancing oxygen evolution reaction

Coordination polymers (CPs) have great potential to be used in electrocatalysis owing to their designable compositions and structures. It is highly challenging to apply CPs as electrocatalysts for oxygen evolution reaction (OER) on account of insufficient catalytic efficiency and relatively poor stability of current electrocatalysts. Herein, through a mixed-metal strategy, one-dimensional CoxNi1-x-HIPA with dual active sites was synthesized and studied for OER electrocatalysts. By changing the metal ratio of CoxNi1-x-HIPA, the OER performance was well regulated. The optimized Co1/2Ni1/2-HIPA exhibited minimum reaction activation energy, and represented an overpotential of 367 mV to reach 10 mA/cm2 at 25 °C. Moreover, an overpotential of 314 mV at 10 mA/cm2 was obtained from Co1/2Ni1/2-HIPA at 55 °C. This mixed-metal strategy provides a feasible way for adjusting the electronic states of the electrocatalysts to improve the electrocatalytic OER performance.