Amine Group Ligand-Modified Hydrotalcite-Like Nano Cobalt Hydroxide for Efficient Oxygen Evolution Reaction

The advancement of highly-efficient, non-noble metal electrocatalysts with high active sites for oxygen evolution reaction (OER) continues to face severe challenges. In this work, a new 3D flower-like a-Co(OH)2 catalyst with high Co-NH2 active sites (referred to as a-Co(OH)2-NH2) is prepared. The Co-NH2 active sites are formed through the interactions between Co2} and-NH2 groups and exhibit higher electrocatalytic performance for OER in alkaline mediums, with a lower overpotential (300 mV at 10 mA cm-2), a flatter Tafel slope (75 mV dec-1) and a longer stability. Moreover, water splitting catalyzed by a-Co(OH)2-NH2 delivers 1.62 V to reach a current density of 10 mA cm-2. The mechanism studies show that the OER electrocatalytic activity is closely related to the content of-NH2. Density functional theory (DFT) calculations unveil that-NH2 groups can facilitate the formation of OH* on the a-Co(OH)2 surface and promote the desorption of O2* into O2(g). (c) 2021 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.