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

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^[rad]−, O₂^[rad]−, h⁺, and ^[rad]ΟΗ, especially SO₄^[rad]−, 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.