Synergistic Conversion of Hydrogen Peroxide and Benzaldehyde in Air by Silver Single-Atom Modified Thiophene-Functionalized g-C3N4

Abstract

This study reports the synthesis of silver single-atom-loaded thiophene-conjugated carbon nitride (Ag@T─C₃N₄), a material with high carrier concentration and efficient carrier separation. Under visible light, Ag@T─C₃N₄ catalyzes hydrogen peroxide (H₂O₂) production and benzyl alcohol oxidation to benzaldehyde, achieving production rates of 4729.82 µmol·g⁻¹·h⁻¹ for H₂O₂ and 19.71 mmol·g⁻¹·h⁻¹ for benzaldehyde. The synergy between thiophene conjugation and silver atoms extends visible light absorption and accelerates the 2-electron oxygen reduction reaction (ORR), enhancing H₂O₂ yield. Photogenerated holes oxidize benzyl alcohol to benzaldehyde, while the biphasic benzaldehyde-water system enables spontaneous product separation. In situ Raman spectroscopy, rotating disk electrode testing, EPR, GC-MS, and DFT calculations highlight the critical role of thiophene-silver synergy in optimizing reaction pathways, enhancing catalyst-intermediate interactions, and reducing Gibbs free energy, improving H₂O₂ and benzaldehyde synthesis. This study provides new insights for designing carbon nitride-based photocatalysts and offers a strategy for co-producing value-added chemicals.