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 H 2 O 2 decomposition. However, their broad applications in practical settings have been hampered by the low efficiency of H 2 O 2 decomposition. Here, we report that metal sulfides (MoS 2 , WS 2 , Cr 2 S 3 , CoS 2 , PbS, or ZnS) can serve as excellent co-catalysts to greatly increase the efficiency of H 2 O 2 decomposition and significantly decrease the required dosage of H 2 O 2 and Fe 2+ in AOPs. Unsaturated S atoms on the surface of metal sulfides can capture protons to form H 2 S and expose metallic active sites with reductive properties to accelerate the rate-limiting step of Fe 3+ /Fe 2+ 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.