Artificial manganese nanozyme for nonradical activation of periodate toward pH-universal water decontamination

Abstract

Single-atom nanozymes (SAzymes), designed to mimic the active centers of natural enzymes, are emerging as a versatile catalytic platform for heterogeneous catalysis. Herein, enzyme-mimicking single-atom manganese (EMSA-Mn) sites supported on graphitic carbon nitride (g-C₃N₄) were constructed, marking a pioneering application of EMSA-Mn-C₃N₄ for periodate (PI; IO₄⁻)-based advanced oxidation processes (AOPs). The EMSA-Mn-C₃N₄/PI system demonstrated remarkable efficiency in eliminating organic micropollutants across a broad pH range (pH 3–11). The positively charged EMSA-Mn sites facilitated the adsorption of the negatively charged IO₄⁻, forming the EMSA-Mn-PI∗ complex, subsequently triggering a direct electron-transfer process (ETP) for oxidation of the organic pollutants. Experimental and theoretical results revealed that the EMSA-Mn site possesses higher intrinsic activity than conventional SA-Mn sites anchored on g-C₃N₄, thereby achieving higher efficiency for PI activation via the ETP. This work provides an advanced design strategy to construct Mn SAzymes for environmental catalysis and deeper insights into the nonradical PI-AOP systems.