Platinum single-atom catalysts (SACs) are promising for electrocatalysis, but the nature of active Pt sites remains elusive. This study identifies the stabilization of low-coordinated PtII species on carbon-based Pt SACs as critical for the chlorine evolution reaction (CER). Advanced spectroscopic studies reveal multiple PtII moieties beyond the ideal four-coordinated PtII-N4. Decreasing Pt content to 0.15 wt.% highlights the role of low-coordinated PtII species in CER. This work provides guidelines for enhancing electrocatalytic performance of carbon-based SACs using other dn metal ions.

Junsic Cho, Taejung Lim, Haesol Kim, Ling Meng, Jinjong Kim, Seunghoon Lee, Jong Hoon Lee, Gwan Yeong Jung, Kug-Seung Lee, Francesc Viñes, Francesc Illas, Kai S. Exner, Sang Hoon Joo, Chang Hyuck Choi