A Site Distance Effect Induced by Reactant Molecule Matchup in Single‐Atom Catalysts for Fenton‐Like Reactions

Abstract Understanding the site interaction nature of single‐atom catalysts (SACs), especially densely populated SACs, is vital for their application to various catalytic reactions. Herein, we report a site distance effect, which emphasizes how well the distance of the adjacent copper atoms (denoted as d Cu1−Cu1 ) matches with the reactant peroxydisulfate (PDS) molecular size to determine the Fenton‐like reaction reactivity on the carbon‐supported SACs. The optimized d Cu1−Cu1 in the range of 5–6 Å, which matches the molecular size of PDS, endows the catalyst with a nearly two times higher turnover frequency than that of d Cu1−Cu1 beyond this range, accordingly achieving record‐breaking kinetics for the oxidation of emerging organic contaminants. Further studies suggest that this site distance effect originates from the alteration of PDS adsorption to a dual‐site structure on Cu 1 −Cu 1 sites when d Cu1−Cu1 falls within 5–6 Å, significantly enhancing the interfacial charge transfer and consequently resulting in the most efficient catalyst for PDS activation so far.