Dual H₂O₂ production paths over chemically etched MoS₂/FeS₂ heterojunction: Maximizing self-sufficient heterogeneous Fenton reaction rate under the neutral condition

Sufficient generation of H₂O₂ played an essential role in boosting self-sufficient heterogeneous Fenton reaction. Herein, the dual H₂O₂ production paths were designed to maximize the yield over H₂O₂-etched MoS₂/FeS₂ Z-scheme heterojunction, whose surface was modified with abundant –OH groups and sulfur vacancies (SVs). Mechanism studies revealed that H₂O₂ was generated via two-step single-electron reduction by electrons on conduction band, where H₂O₂ production was significantly improved by the internal hole-scavenging effect from –OH groups. Additionally, electrons surrounding SVs served as another sites for H₂O₂ production via one-step two-electron reduction even in darkness. H₂O₂ yield in neutral aqueous solution reached 1.5 mM/g/h without external hole scavenger. Tetracycline and rhodamine B were effectively degraded under light or in darkness. The degradation performance was even comparable to the heterogeneous Fenton reaction. This work provides new insights for the design of self-sufficient heterogeneous Fenton system with exceptional degradation performance.