Visible-light photoelectrocatalysis/H2O2 synergistic degradation of organic pollutants by a magnetic Fe3O4@SiO2@mesoporous TiO2 catalyst-loaded photoelectrode

In this paper, we describe a method for photoelectrocatalysis (PEC)/H2O2 synergistic degradation of organic pollutants with a magnetic Fe3O4@SiO2@mesoporous TiO2 (FST) photocatalyst-loaded electrode. At optimal conditions of pH 3.0, 2.25% H2O2, working electrode (fixed FST 30 mg) potential +0.6 V (vs. SCE), and 10 mg L-1 of all experimental pollutants, the FST PEC/H2O2 synergistic system exhibited high activity and stability for the removal of various organic pollutants under visible light with comparable degradation efficiencies, including MB (98.8%), rhodamine B (Rh B, 96.7%), methyl orange (MO, 97.7%), amoxicillin (AMX, 83.9%). Moreover, this system obtained TOC removal ratios of 83.5% (MB), 77.9% (Rh B), 80.2% (MO), 65.5% (AMX) within 8 min. The kinetic rate constants of the PEC/H2O2 synergistic system were nearly 53 and 1436 times higher than that of the PEC process and H2O2 photolysis under visible light, respectively. Furthermore, the main reactive oxidant species (OH, O-2(-)) were studied and enhanced mechanisms of the photocatalytic-electro-H2O2 coupling system were proposed. This work brings new insights to efficiently purify organic pollutants by PEC coupled with peroxide under solar light illumination.

Automated summary

This paper presents a new method for the photoelectrocatalysis (PEC)/H2O2 synergistic degradation of organic pollutants. The results showed that the system exhibited high activity and stability for the removal of various organic pollutants under visible light. The study also proposed enhanced mechanisms of the photocatalytic-electro-H2O2 coupling system.