Computational study of electrocatalytic chlorine evolution reaction over transition metal-embedded porphyrin substrates

Abstract Chlorine, a chemical of significant importance, has been produced in a chlor-alkali process utilizing dimensionally stable anodes (DSAs) for a long time. However, the inherent limitations of DSAs have prompted the exploration of alternative electrocatalysts for the chlorine evolution reaction (CER). In this study, we focus on a transition metal (TM) incorporated in the porphyrin center (TMP) as an electrocatalyst toward anodic CER, which has been theoretically investigated based on the quantum chemical density functional theory method. Out of the studied substrates, CoP, NiP, and PtP exhibited significant CER activity with reasonably low overpotentials (−106, 215, and 218 mV, respectively) in the Volmer–Heyrovsky mechanism via the desired Cl* intermediate instead of ClO*. Furthermore, the active electrocatalysts showed excellent selectivity towards CER because of the elevated overpotentials and reaction barriers in the oxygen evolution reaction. This may facilitate the development of a CER electrocatalyst that utilizes a TM-embedded porphyrin-like template.