Interfacial Microenvironment Engineering of Carbon-Doped Carbon Nitride-Wrapped SnO2 Nanofibers for Efficient Overall Photocatalytic H2O2 Production

Photocatalytic H2O2 production offers a sustainable alternative to the energy-intensive anthraquinone process, yet its efficiency is limited by rapid charge recombination, sluggish oxygen activation, and mismatched interfacial environments. Herein, a hierarchical heterostructure of carbon-doped carbon nitride nanosheets tightly wrapped on SnO2 nanofibers (C-PCN/SnO2) is constructed via one-step calcination of electrospun Sn2+-containing polyvinylpyrrolidone (PVP) nanofibers mixed with bulk carbon nitride precursor, during which Sn-PVP converts to SnO2 nanofibers while PVP decomposition simultaneously induces in situ exfoliation of bulk carbon nitride and carbon self-doping, forming a closely contacted heterojunction. Experimental and theoretical results reveal that the built-in electric field at the heterointerface drives S-scheme charge separation, preserving highly reductive electrons and oxidative holes. Notably, C-PCN serves as an efficient oxygen adsorption and activation domain, whereas hydrophilic SnO2 facilitates water-involved oxidation, jointly optimizing the interfacial reaction microenvironment. Benefiting from this synergy, the optimized heterojunction achieves a H2O2 production rate of 31.09 μM h–1 under visible light without sacrificial agents or cocatalysts, 7.6 and 12.5 times higher than C-PCN and SnO2, respectively. This work provides a new insight into reaction microenvironment engineering for efficient solar-driven H2O2 production.