Heterostructure engineering of resorcinol-formaldehyde resins and sulfur-vacancy-containing Zn3In2S6 for high-efficiency photocatalytic H2O2 production

Resorcinol-formaldehyde (RF) resins have garnered significant interest due to their remarkable efficiency in producing photocatalytic H2O2. The combination of RF with inorganic semiconductors to create organic-inorganic heterojunctions represents a promising strategy for enhancing photocatalytic activity. In this work, RF was coated onto Zn3In2S6 nanoflowers with sulfur-vacancy, creating RF/Zn3In2S6 composites with an Sscheme heterostructure. This novel composite exhibited superior photocatalytic activity for H2O2 production in both pure water and seawater, without sacrificial agents. Specifically, the production rate of RF/Zn3In2S6-0.3 in pure water under simulated solar illumination achieved 3174.34 mu mol/h/g, marking 8.53 and 4.17 times over RF and Zn3In2S6, respectively. Moreover, its photocatalytic activity in seawater reached an impressive 2290.81 mu mol/h/g, 4.93 and 3.12 times greater than that of RF and Zn3In2S6, respectively. The enhanced photocatalytic activity is attributed to the S-scheme charge transfer mechanism, which facilitates efficient charge separation and amplifies redox capabilities. Both experimental and density function theory analyses confirm the S-scheme route in RF/Zn3In2S6-0.3 for photocatalytic H2O2 production. This study not only presents the first account of an organic semiconductor RF being employed in an S-scheme heterojunction interface but also introduces the surface sulfur-vacancy mediated S-scheme heterojunction strategy for photocatalytic H2O2 production, representing a significant advancement in the field.