Integrating Hydrogen Production with Aqueous Selective Semi-Dehydrogenation of Tetrahydroisoquinolines over a Ni2P Bifunctional Electrode

Exploring an alternative anodic reaction to produce value-added chemicals with high selectivity, especially integrated with promoted hydrogen generation, is desirable. Herein, a selective semi-dehydrogenation of tetrahydroisoquinolines (THIQs) is demonstrated to replace the oxygen evolution reaction (OER) for boosting H-2 evolution reaction (HER) in water over a Ni2P nanosheet electrode. The value-added semi-dehydrogenation products, dihydroisoquinolines (DHIQs), can be selectively obtained with high yields at the anode. The controllable semi-dehydrogenation is attributed to the in situ formed Ni-II/Ni-III redox active species. Such a strategy can deliver a variety of DHIQs bearing electron-withdrawing/donating groups in good yields and excellent selectivities, and can be applied to gram-scale synthesis. A two-electrode Ni2P bifunctional electrolyzer can produce both H-2 and DHIQs with robust stability and high Faradaic efficiencies at a much lower cell voltage than that of overall water splitting.