Interfacial Charge Regulation of AgInS2/KGF10 Heterojunction Promoting H2O2 Production via Two Distinct O2/H2O Photocatalytic Routes

Abstract

Photocatalytic hydrogen peroxide (H2O2) production via the oxygen reduction reaction (ORR) and water oxidation reaction (WOR) is a sustainable alternative to the energy-intensive anthraquinone process, but it is constrained by the lack of efficient photocatalysts capable of integrating both ORR and WOR dual pathways. Herein, we report an efficient Z-scheme AIS/KGF10 heterojunction fabricated by the in situ growing silver indium sulfide (AgInS2) nanoparticles on a sulfur-rich Sn-based metal–organic framework (KGF10) for efficient dual-pathway H2O2 production. The intimate interfacial contact and porous structure as well as large specific surface area of AIS/KGF10 heterojunctions enhance reactant adsorption and charge transfer. The optimized AIS/KGF10–2 wt % heterojunction exhibits a maximum H2O2 yield of 1.057 mmol g–1 h–1, outperforming pristine AIS (0.254 mmol g–1 h–1) and KGF10 (0.350 mmol g–1 h–1) significantly. Mechanistic studies confirm that the Z-scheme charge transfer efficiently prolongs the electron lifetime of photogenerated carriers to 2.84 ns while retaining strong redox capabilities for ORR and WOR. Rotating disk electrode (RDE) measurements verify ORR proceeds via a two-electron pathway, indicating that the 2e– ORR pathway is reasonably feasible in photocatalytic H2O2 production. Electron paramagnetic resonance (EPR) and in situ FTIR spectroscopy confirm key intermediates (•O2–, •OH, and *OOH) and the synergistic ORR-WOR mechanism. This work provides a new strategy for constructing dual-functional heterojunction systems by integrating semiconductors with S-MOFs, offering valuable insights for sustainable H2O2 production.