Efficient visible light photocatalytic NO abatement over SrSn(OH)6 nanowires loaded with Ag/Ag2O cocatalyst

SrSn(OH)6 (SSOH) possesses a high oxidation potential in the valence band (VB), which is suitable for photocatalytic oxidation removal of pollutants. However, the electrons in the VB of these catalysts are difficult to transition to the conduction band (CB) under visible light, which makes it difficult to utilize sunlight effectively. In this work, Ag/Ag2O is loaded on the surface of SSOH nanowires, which stimulates the interfacial chargetransfer transition on SSOH. Compared with pure-phase SSOH, the NO abatement ratio of Ag/Ag2O-SSOH under visible light irradiation is increased to 45.10%. The e- in the VB of Ag2O are excited into the CB under visible light, and are further transferred to the Ag to react with O2 to produce superoxide radicals. The photoexcited e- in the VB of SSOH enter into the VB of Ag2O through interfacial charge-transfer transition to recombine with the photo-generated holes in the VB of Ag2O, thereby leaving photo-generated holes in the VB of SSOH. The holes in the VB of SSOH have sufficient oxidizing ability to oxidize the adsorbed hydroxyl groups into hydroxyl radicals. This work provides a new perspective for photocatalytic removal of pollutants by wide band gap photocatalyst under visible light.

Automated summary

In this study, Ag/Ag2O loaded on SrSn(OH)6 nanowires promotes interfacial charge-transfer transition, leading to enhanced NO removal under visible light. Excited electrons in the VB of Ag2O enter the CB under visible light, reacting with Ag to produce superoxide radicals, allowing holes in the VB of SSOH to oxidize hydroxyl groups into hydroxyl radicals.