Coupling Plant Polyphenol Coordination Assembly with Co(OH) 2 to Enhance Electrocatalytic Performance towards Oxygen Evolution Reaction.

The oxygen evolution reaction (OER) is kinetically sluggish due to the limitation of the four-electron transfer pathway, so it is imperative to explore advanced catalysts with a superior structure and catalytic output under facile synthetic conditions. In the present work, an easily accessible strategy was proposed to implement the plant-polyphenol-involved coordination assembly on Co(OH) ₂ nanosheets. A TA-Fe (TA = tannic acid) coordination assembly growing on Co(OH) ₂ resulted in the heterostructure of Co(OH) ₂ @TA-Fe as an electrocatalyst for OER. It could significantly decrease the overpotential to 297 mV at a current density of 10 mA cm ^-2 . The heterostructure Co(OH) ₂ @TA-Fe also possessed favorable reaction kinetics with a low Tafel slope of 64.8 mV dec ^-1 and facilitated a charge-transfer ability. The enhanced electrocatalytic performance was further unraveled to be related to the confined growth of the coordination assembly on Co(OH) ₂ to expose more active sites, the modulated surface properties and their synergistic effect. This study demonstrated a simple and feasible strategy to utilize inexpensive biomass-derived substances as novel modifiers to enhance the performance of energy-conversion electrocatalysis.