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 α-Co(OH) 2 catalyst with high Co–NH 2 active sites (referred to as α-Co(OH) 2 –NH 2 ) is prepared. The Co–NH 2 active sites are formed through the interactions between Co 2+ and –NH 2 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 α-Co(OH) 2 –NH 2 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 –NH 2 . Density functional theory (DFT) calculations unveil that –NH 2 groups can facilitate the formation of OH∗ on the α-Co(OH) 2 surface and promote the desorption of O 2 ∗ into O 2(g) .