Metallic Ni as Electron Acceptor Modulates the Redox of Catalytic Centers at Activated Ni0/Ni(OH)2 Heterojunctions for Efficient Ethanol Electrooxidation.

The coproduction of high-value-added acetate and hydrogen fuel by ethanol-assisted water electrolysis is significant, but the efficiency of ethanol electrooxidation (EOR) is hindered both by sluggish kinetics, primarily dictated by the redox properties of the catalyst. Therefore, the development of efficient EOR electrocatalysts has to target optimized redox properties. Herein, a Ni0/Ni(OH)2 heterostructure was synthesized by inducing a shift from hydrophilic to hydrophobic properties on the electrode surface during electrochemical deposition. The electrocatalyst enabled a current density of 573.7 mA cm-2 at 1.37 V versus RHE for EOR with a solar-to-hydrogen conversion efficiency of 14.4% when coupled to a commercial solar panel. Experimental and theoretical results disclosed that the incorporation of Ni0 facilitates the ethanol to acetate kinetics through enhanced Ni2+ to Ni3+ conversion. The strategy, combining hydrogen production with the synthesis of value-added products, enhances economic viability compared to conventional water electrolysis, underscoring its promise for practical implementation.