Accelerating H2 Evolution by Anodic Semi‐dehydrogenation of Tetrahydroisoquinolines in Water over Co3O4 Nanoribbon Arrays Decorated Nickel Foam

Coupling the H2 evolution reaction in water with thermodynamically favorable organic oxidation reactions is highly desirable, because it can enhance the energy conversion efficiency compared with electrocatalytic water splitting, and produce value‐added chemicals instead of O2 in the anodic reaction. Herein, Co3O4 nanoribbon arrays in situ grown on nickel foam (Co3O4@NF) was employed as an effective electrocatalyst for the selective oxidation of tetrahydroisoquinolines (THIQs). Various value‐added semi‐dehydrogenation products including dihydroisoquinolines with electro‐deficient or ‐rich groups could be obtained with moderate yields and faradaic efficiencies. Benefitting from the rich surface active sites of Co3O4@NF, a two‐electrode (Co3O4@NF||Pt) electrolytic system drove a benchmark current density of 10 mA cm−2 at a cell voltage as low as 1.446 V in 1.0 M KOH aqueous solution containing 0.02 M THIQ, which was reduced by 174 mV in comparison with that of overall water splitting. Semi‐dehydrogenation conversion based on a cobalt electrocatalyst was employed to accelerate hydrogen evolution in water. The Co3O4 nanoribbon arrays modified nickel foam anode provided rich active sites for the transformation of tetrahydroisoquinolines into various value‐added dihydroisoquinolines. Electro‐activated higher‐valent cobalt and plenty of surface oxygen species were responsible for promoting the electrocatalytic oxidation.