An efficient heterogeneous catalyst of FeCo2O4/g-C3N4 composite for catalytic peroxymonosulfate oxidation of organic pollutants under visible light

[Display omitted] •FeCo2O4/g-C3N4 composites were successfully fabricated as heterogeneous catalyst.•The 3%FeCo2O4/CN catalyst with PMS removes 98% RhB at 45 min under visible light.•There is a synergistic effect between the photocatalytic processes and the Fenton-like processes.•The main radical species (i.e., SO4−) play a dominant role in the degradation of RhB.•Simple calcination regenerated the catalytic capacity of 3%FeCo2O4/CN for reuse. It is a long-term goal to develop catalysts with high activity and stability in practical applications. Spinel FeCo2O4 has been widely researched in heterogeneous catalysis due to its characteristics of stable structure and environmental friendliness. In this work, the composites of graphitic carbon nitride (g-C3N4) and spinel iron cobaltate (FeCo2O4) have been fabricated and used to degrade rhodamine B (RhB) by combining the photocatalytic and Fenton-like reactions. The composite with 3% FeCo2O4 (3%FeCo2O4/CN) showed the best degradation efficiency, with which about 98% RhB was degraded in 45 min. The catalytic activity of 3%FeCo2O4/CN was larger than that of FeCo2O4, g-C3N4, and their mechanical mixture. The synergetic interaction between photocatalytic and Fenton-like reactions and the effective separation of the photogenerated charges are responsible for the enhanced catalytic activity. The quenching and EPR experiments exhibit that SO4−, O2−, h+, and ΟΗ, especially SO4−, are involved in the removal of RhB. The cycle experiments confirm that the used catalyst can restore its catalytic activity after calcination at 400 °C. The work suggests that the composites show a good ability to degrade organic pollutants in wastewater.