Interface engineering of Z-scheme α-Fe2O3/g-C3N4 photoanode: Simultaneous enhancement of charge separation and hole transportation for photoelectrocatalytic organic pollutant degradation

A series of g-C3N4-modified α-Fe2O3 heterostructures are synthesized by deposition on fluorine-doped tin oxide (FTO). The resulting α-Fe2O3/g-C3N4/FTO photoanode (denoted as Fe/CN) show markedly improve photoelectrocatalytic performance, with a photocurrent density (0.18 mA/cm2) that is 5.1 times that of α-Fe2O3 and 9.4 times that of g-C3N4. The suitable charge transport path is observed by interfacial analysis, where the conduction band of g-C3N4 and valence band of α-Fe2O3 shuttled holes and electrons into the electrolyte at accelerated speeds, respectively. Impressively, the Fe/CN photoelectrode achieve the highest pollutant removal efficiency of 99.7% for the photoelectrocatalytic degradation of clofibric acid (CA) under visible-light irradiation, which is expected to be applicable in actual wastewater for environmental protection. Density functional theory (DFT) calculations and intermediate identification shows that the CA degradation pathway involved C–Cl and O–C cleavage. These findings provide an environmentally friendly method to remove emerging contaminants using renewable solar energy.