Metal Sulfides as Excellent Co-catalysts for H2O2 Decomposition in Advanced Oxidation Processes

Advanced oxidation processes (AOPs) are widely proposed for treating persistent pollutants by the, OH radicals generated from H2O2 decomposition. However, their broad applications in practical settings have been hampered by the low efficiency of H2O2 decomposition. Here, we report that metal sulfides (MoS2, WS2, Cr2S3, CoS2, PbS, or ZnS) can serve as excellent co-catalysts to greatly increase the efficiency of H2O2 decomposition and significantly decrease the required dosage of H2O2 and Fe2+ in AOPs. Unsaturated S atoms on the surface of metal sulfides can capture protons to form H2S and expose metallic active sites with reductive properties to accelerate the rate-limiting step of Fe3+/Fe2+ conversion. The efficiency of AOPs involving co-catalysts can be further enhanced by visible-light illumination thanks to the sensitization of organic pollutants. This discovery is expected to drive great advances in the use of AOPs for large-scale practical applications such as environmental remediation.