Enhancing Reactive Oxygen Species Generation and Pollutant Adsorption in Advanced Oxidation Processes with Cation Vacancy-Driven Dual-Site Mn2SiO4 Catalysts

Abstract

Catalytic advanced oxidation processes (AOPs) have emerged as a promising strategy for the near-complete mineralization of all-organic pollutants via the strong oxidizing power of reactive oxygen species (ROS). However, practical implementation is hindered by the low ROS generation yield owing to insufficient catalytically active sites and ineffective utilization stemming from transient radical lifetimes. Herein, cation vacancy-engineered manganese silicate (V-Mn₂SiO₄) catalysts comprising dual reaction sites are presented, which enable the highly efficient oxidation of recalcitrant organic pollutants through the activation of peroxymonosulfate. Experimental results and density functional theory calculations confirm that Mn sites adjacent to vacancies serve as the primary active centers for peroxymonosulfate activation, whereas adjacent O sites facilitate pollutant adsorption. This dual-site configuration effectively lowers the activation energy barrier and enhances peroxymonosulfate activation and singlet oxygen (¹O₂) generation while optimizing the ¹O₂ migration distance via pollutant adsorption and enrichment. The rate constants of V-Mn₂SiO₄ against rhodamine B and 2,4-dichlorophenol pollutants are 1.171 and 0.1291 min⁻¹, respectively, which are comparable to those reported for atomically dispersed metal nanocatalysts in AOPs. This discovery marks a breakthrough in AOPs, accelerating their practical application in environmental remediation and advancing sustainable pollution control technologies.