Mn/S diatomic sites in C₃N₄ to enhance O₂ activation for photocatalytic elimination of emerging pollutants

Oxygen activation leading to the generation of reactive oxygen species (ROS) is essential for photocatalytic environmental remediation. The limited efficiency of O₂ adsorption and reductive activation significantly limits the production of ROS when employing C₃N₄ for the degradation of emerging pollutants. Doping with metal single atoms may lead to unsatisfactory efficiency, due to the recombination of photogenerated electron-hole pairs. Here, Mn and S single atoms were introduced into C₃N₄, resulting in the excellent photocatalytic performances. Mn/S-C₃N₄ achieved 100% removal of bisphenol A, with a rate constant 11 times that of pristine C₃N₄. According to the experimental results and theoretical simulations, S-atoms restrict holes, facilitating the photo-generated carriers’ separation. Single-atom Mn acts as the O₂ adsorption site, enhancing the adsorption and activation of O₂, resulting the generation of ROS. This study presents a novel approach for developing highly effective photocatalysts that follows a new mechanism to eliminate organic pollutants from water.