A Z-scheme LaFeO3-CuFe2O4 composite for sulfate radical-based photocatalytic process: Synergistic effect and mechanism

The sulfate radical-based photocatalytic process is supposed to be the most promising way to degrade organic pollutants. However, the development of a suitable and efficient photocatalyst is very challenging. The 40LaFeO₃-CuFe₂O₄ (40LFO-CFO) nanocomposite was constructed and its catalytic performance was studied using Rhodamine B (RhB) as the target pollutant. 40LFO-CFO exhibited excellent RhB degradation by the persulfate (PS)-assisted photocatalytic process compared to the pristine LFO and CFO. The degradation rate constant for RhB by 40LFO-CFO in the Vis/PS system was 2.22 h⁻¹ which is 3.04 times and 5.05 times higher than the pristine LFO (0.73 h⁻¹) and CFO (0.44 h⁻¹), respectively. Furthermore, the trapping experiments and EPR spectra proved that h⁺ plays a leading role in the bleaching of RhB for the 40LFO-CFO/PS/Vis system. The enhanced photocatalytic oxidation activity of 40LFO-CFO could be attributed to the unique charge carriers flow in 40LFO-CFO due to the Z-scheme and the cooperation effect between photocatalysis and PS activation. The recycle tests confessed the stability of 40LFO-CFO. Additionally, the intermediates and products of RhB are detected by liquid chromatography-mass spectrometry (LC-MS), and the photocatalytic degradation routes of RhB for the 40LFO-CFO/Vis/PS system were proposed. Moreover, the 40LFO-CFO nanocomposite has a superior catalytic performance for other organics, suggesting that it is a promising heterocatalyst because of its high catalytic activity and stability for the PS-assisted photocatalytic process.