Functional Carbon Nitride Materials in Photo-Fenton-Like Catalysis for Environmental Remediation

Abstract

Among various advanced oxidation processes, coupled photocatalysis and heterogeneous Fenton-like catalysis (known as photo-Fenton-like catalysis) to generate highly reactive species for environmental remediation has attracted wide interests. As an emerging metal-free photocatalyst, graphitic carbon nitride (g-C3N4, CN) has been recently recognized as a promising candidate to catalyze robustly heterogeneous photo-Fenton-like reactions for wastewater remediation. This review summarizes recent progress in fabricating various types of CN-based catalysts for the photo-Fenton-like reaction process. Innovative engineering strategies on the CN matrix are outlined, ranging from morphology control, defect engineering, nonmetal atom doping, organic molecule doping to modification by metal-containing species. The photo-Fenton-like catalytic activities of CN loaded with auxiliary sub-nanoscale (e.g., quantum dots, organometallic molecules, metal cations, and single atom metals) and nanoscale metal-based materials are critically evaluated. Hybridization of CN with bandgap-matching semiconductors for the construction of type-II and Z-scheme heterojunctions are also examined. The critical factors (e.g., morphology, dimensionality, light absorption, charge excitation/migration, catalytic sites, H2O2 generation and activation) that determine the performance of CN-based photocatalysts in Fenton-like catalysis are systematically discussed. After examining the structure–activity relationship, research perspectives are proposed for further development of CN-based photocatalysts toward more efficient photo-Fenton-like reactions and their application in practical water treatment.