Electrocatalytic water splitting represents a promising way to produce clean hydrogen (H2). However, the oxygen evolution reaction (OER), which is the half-reaction of water splitting, is sluggish and yields little value. There are additional problems such as separating oxygen and hydrogen. These factors often limit overall water splitting efficiency. An alternative strategy is to replace anode OER with the electro-oxidation of more thermodynamically favorable and high value-added chemicals. In this regard, coupling elctrocatalytic organic oxidation and hydrogen production is highly desirable for reducing energy consumption and raising a value-added reaction.
Professor Zhang Bing’s group from Tianjin University’s School of Science found that the in-situ formed high valence metal of anode catalyst materials, acted as the real redox active species to drive the organic oxidation reaction on the basis of their prior research on anodic oxidation of primary amines and identification of the active species of anode catalyst materials. Professor Zhang’s research group proposed to replace OER with selective semi-dehydrogenation of tetrahydroisoquinolines (THIQs), and developed a strategy of integrating hydrogen production with aqueous selective semi-dehydrogenation of THIQs over a Ni2P bifunctional electrode.
By replacing OER with thermodynamically more favorable THIQs selective oxidation, the cell voltage of this reaction system is notably reduced (when achieving the current density of 20 mAcm-2requires a 300 mV smaller voltage than that of overall water splitting), which effectively decreased energy consumption of hydrogen production. At the same time, it can produce dihydroisoquinolines (DHIQs) via a sustainable route by highly selective semi-dehydrogenation of THIQs at a low potential. Impressively, the bifunctional Ni2P electrodes can be assembled into a two-electrode electrolyzer for both hydrogen production and gram scale semi-dehydrogenation of THIQs with excellent yields driven by a 1.5 V single-cell battery. This work opens an economical and highly efficient route for the electrochemical production of both hydrogen and organic chemicals.
By the School of Science
Editors: Eva Yin & Doris Harrington
