Toward efficient cobalt-based oxygen evolution reaction: heteropolyatomic anion-inductive effect

Abstract

Despite the great progress in oxygen evolution reaction catalyst research, obtaining desired coordination environment and optimized electronic structure of active center remains challenging. Here, we propose a feasible strategy of changing the local coordination chemical environment of the active cations via introducing hetero-polyatomic anions based on the crystal field theory. A new type of two-dimensional Co-NO3-OAC[x:y]-hexamine (HMT) catalyst is first prepared in a water bath (OAC= CH3COO-). It is discovered that adding OAC− into nanosheets containing NO3− can regulate both the morphologies and the electronic structure of as-prepared Co-based catalysts. As a result, the optimized Co-NO3-OAC[6:4]-HMT nanosheet aggregates exhibits an overpotential as low as 307 mV at the current density of 10 mA cm−2 and a small Tafel slope (62 mV/dec). Moreover, the voltage attenuation of electrolysis in the 1 M KOH alkaline medium for 10 h is only 8 mV. This superior electrochemical performance can be attributed to the induction effect of hetero–polyatomic anions. Our discovery provides a new insight into understanding the design of electrocatalysis based on anionic coordination chemistry.