Carbon nitride in peroxide-coupled photocatalysis for aqueous organic pollutants destruction: Engineered active sites and electron transfer regimes

Heterogeneous Fenton-like photocatalytic reactions are potent in environmental remediations because of the synergisms of highly active photoelectrons for sustainable activation of peroxides. Such high energy electrons can stimulate the breakage of the peroxyl bond (O-O) to evolve reactive oxygen species (ROS) and improve the photocatalytic efficiency. Graphitic carbon nitride (g-C3N4) has received broad research attention in wastewater decontamination owing to its high intrinsic photocatalytic activity and strong interactions with peroxides. This review summarizes the recent research progress of the applications of g-C3N4-based catalysts in peroxide-coupled photocatalytic reactions. Photo-induced electron transfer regimes for peroxides activation towards ROS generation are scrutinized and categorized. And the engineered strategies to optimize the physio-chemical properties and electronic states of g-C3N4 to efficiently drive photo-Fenton catalysis are outlined. Challenges and future research opportunities are also proposed for the photocatalysts design, mechanisms exploration, and practical implementation possibilities.