Atomic Pt-N-4 Sites in Porous N-Doped Nanocarbons for Enhanced On-Site Chlorination Coupled with H-2 Evolution in Acidic Water

Acidic water electrolysis (AWE) has the potential to revolutionize green H-2 generation with flexible partial load range, high gas purity, and rapid system response. However, the extensive usage of noble Ru/Ir metals and sluggish oxygen evolution reaction (OER) with inexpensive O-2 products pose significant challenges in anodes. Herein, it is demonstrated that ultralow Pt single atoms in highly porous N-doped carbons (Pt-1/p-NC@CNTs) can effectively catalyze chlorine evolution reaction (CER) for on-site chlorination to replace OER in AWE, with 200 mV potential saving at 10 mA cm(-2). As a result, various organic halide motifs of pharmaceutical molecules by chlorinating anisole, ketones, and olefins can be realized, along with H-2 coproduction. Combined physicochemical characterizations including synchrotron X-ray absorption spectroscopy, finite element methodsimulations, and theory calculations indicate that atomic Pt-N-4 active sites balance the adsorption/desorption of Cl intermediates (Volmer step) and the plentiful porosity of Pt-1/p-NC@CNTs with high specific surface area of 313 m(2) g(-1 )enriches Cl(- )around active sites (Heyrovsky step), collectively promoting the rate-limiting Volmer-Heyrovsky pathway for improved CER.