Activity Origins and Design Principles of Nickel-Based Catalysts for Nucleophile Electrooxidation

Abstract

Summary Understanding how electrocatalysts function in a nucleophile oxidation reaction (NOR) on anode, replacing the oxygen evolution reaction (OER) of water splitting, is vital to the development of hydrogen generation and organic electrosynthesis. Here, we propose that for β-Ni(OH)2 and NiO, the NOR activity origins are β-Ni(OH)O containing electrophilic lattice oxygen and NiO(OH)ads containing electrophilic adsorption oxygen, respectively. For β-Ni(OH)2, NOR is a two-step, one-electron reaction, including an electrogenerated catalyst dehydrogenation reaction and a spontaneous nucleophile dehydrogenation reaction. Therefore, the NOR activity of β-Ni(OH)2 can be markedly regulated by tuning the lattice oxygen ligand environment. For β-Co0.1Ni0.9(OH)2, the onset potential of NOR with different nucleophiles is ∼1.29 V (1 M KOH), which breaks the bottleneck of ∼1.35 V for most nickel-based catalysts. Overall, we identify the activity origins and propose the design principles of nickel-based catalysts for NOR. These provide theoretical guidance for the development of NOR and organic electrosynthesis in practical industrial applications.