Atomically dispersed Pt–N4 sites as efficient and selective electrocatalysts for the chlorine evolution reaction

Abstract Chlorine evolution reaction (CER) is a critical anode reaction in chlor-alkali electrolysis. Although precious metal-based mixed metal oxides (MMOs) have been widely used as CER catalysts, they suffer from the concomitant generation of oxygen during the CER. Herein, we demonstrate that atomically dispersed Pt−N 4 sites doped on a carbon nanotube (Pt 1 /CNT) can catalyse the CER with excellent activity and selectivity. The Pt 1 /CNT catalyst shows superior CER activity to a Pt nanoparticle-based catalyst and a commercial Ru/Ir-based MMO catalyst. Notably, Pt 1 /CNT exhibits near 100% CER selectivity even in acidic media, with low Cl − concentrations (0.1 M), as well as in neutral media, whereas the MMO catalyst shows substantially lower CER selectivity. In situ electrochemical X-ray absorption spectroscopy reveals the direct adsorption of Cl − on Pt−N 4 sites during the CER. Density functional theory calculations suggest the PtN 4 C 12 site as the most plausible active site structure for the CER.