Spatially Separated Molecular Activation Over Dual Sites in Sn-Doped ZnGa₂O₄/SnO₂ Photocatalysts Toward Complete VOCs...

Photocatalysis holds great promise for air pollutant remediation; however, its efficiency is often limited by charge recombination and humidity interference. Herein, Sn-doped ZnGa₂O₄ loaded SnO₂ nanoparticles (SZGO) is in situ constructed via a one-step hydrothermal method. The doped Sn atoms act as electron-trapping centers and form interfacial Sn─O channels between ZnGa₂O₄ and SnO₂, enabling directional electron migration. Hydrophilic ZnGa₂O₄ domains selectively adsorb H₂O, generating hydroxyl radicals (·OH) that facilitate aromatic ring cleavage, while electron-rich SnO₂ domains activate O₂ to produce superoxide (·O₂ ^-) and singlet oxygen (¹O₂), leading to complete degradation of carbonaceous intermediates. The optimized SZGO achieves nearly 100% toluene degradation and 99.2% mineralization efficiency, with excellent stability across a wide humidity range (0-100%) and over 12 continuous cycles (720 min). Additionally, SZGO demonstrates broad-spectrum reactivity toward other volatile organic compounds (VOCs), such as acetone and formaldehyde. This work offers a versatile design strategy that couples directional charge transport with site-specific molecular activation, providing new insights for the development of highly stable photocatalysts for environmental purification.