Highly Active Electrocatalytic Alcohol Oxidation Coupled Hydrogen Production with Unsaturated Ni-O(OH) Coordination

Abstract

Electrocatalytic H2 production coupled with valuable chemical fabrication is a highly desirable and sustainable approach for a carbon-neutral future. The prerequisite for its industrialization on a terawatt scale is the exploitation of an electrocatalyst that can operate steadily at current densities exceeding ampere levels. In this work, a Ni-O(OH)-C electrocatalyst consisting of an unsaturated Ni-O(OH) immobilized Ni crystal confined by carbon layers is proposed to realize the exceptional performance at the ampere-level current densities toward ethanol electrooxidation to acetic acid (EOR), hydrogen evolution reaction (HER), and their integrated system. This catalyst achieves a current density of 1 A cm−2 for EOR and HER at a potential of 1.46 and −0.3 V (vs RHE), respectively. The unsaturated Ni-O(OH) species confined by carbon layers offer an optimized electronic structure and interfacial microenvironment to facilitate the HER kinetics, and they can deliver the electrophilic adsorbed oxygen to induce the EOR and block its unfavorable structural transformations during electrocatalysis. A Ni-O(OH)-C catalytic HER||EOR integration system offers a 220 mV voltage reduction at 1 A cm−2 in comparison to that of Pt/C||RuO2 water electrolysis cell. A Zn-ethanol-air battery is equipped with a Ni-O(OH)-C catalyst, exhibiting >500 h of stable operation. Thanks to the extensive universality of the proposed alcohol systems, findings shine a bright future for the efficient and scalable manufacture of value-added chemicals, together with high-purity hydrogen production.