Z-scheme heterojunction with Fe coordinatively unsaturated metal sites for self-feeding photo-fenton process

The practical application of photo-Fenton processes to degrade contaminants is limited by their poor stability under varying pH environment. The requirement of supplementary oxidants and iron additives increase the cost. This reports the construction of Z-scheme heterojunction with Fe coordinatively unsaturated metal sites (Fe CUMSs) based on g-C 3 N 4 as the highly efficient photo-Fenton catalysts. The optimized catalyst presented stable MB degradation efficiency of 115.32 mg g −1 (pH 4.0), 113.44 mg g −1 (pH 7.0), and 106.35 mg g −1 (pH 9.0) in 30 mins without any oxidants and iron-containing additives. The self-feeding photo-Fenton mechanism was studied in details, suggesting that Fe CUMSs improved the H 2 O 2 generation rate of g-C 3 N 4 to 6.23 μmol L −1 h −1 . A completely reversible Fe 2+ /Fe 3+ conversion process lead to persistent generation of hydroxyl radical to degrade MB without iron precipitation generation. This work presents a new strategy constructing self-feeding photo-Fenton catalytical system to remove contaminants for environmental remediation and sustainability.