Towards full-spectrum (UV, visible, and near-infrared) photocatalysis: achieving an all-solid-state Z-scheme between Ag2O and TiO2 using reduced graphene oxide as the electron mediator. Issue 18 (1st September 2017)

• Record Type: Journal Article
• Authors: Hu, Xiaolin; Liu, Xiang; Tian, Jian; Li, Yujie; Cui, Hongzhi
• Is Part Of: Catalysis science & technology. Volume 7:Issue 18(2017)
• Page Start: 4193
• Page End: 4205
• Publication Date: 2017-09-01
• Subjects: Catalysis -- Periodicals; 541.395
• DOI: 10.1039/c7cy01349c
• Languages: English
• ISSNs: 2044-4753

Abstract

Abstract : We prepare an all-solid-state Z-scheme photocatalyst (RGO–Ag2 O/TiO2 composites) for photocatalytic degradation of tetracycline under UV, visible and NIR light irradiation. Abstract : Making full use of solar energy and achieving high charge separation efficiency are critical factors for the photocatalysis technique. Silver oxide (Ag2 O) was used for photocatalysis due to its broad spectrum response. However, the serious photocorrosion and fast carrier recombination of Ag2 O have limited its practical applications. In this work, we propose a strategy to suppress its photocorrosion and promote charge separation by the construction of an all-solid-state Z-scheme photocatalytic system for photocatalytic degradation of tetracycline (TC) under UV light, visible light, near-infrared (NIR) light and simulated solar light irradiation, which was composed of electron-mediated reduced graphene oxide (RGO)-enwrapped TiO2 nanobelts (NBs) as UV-responsive photocatalysts and visible/NIR-light-driven Ag2 O nanoparticles (NPs). The improved photoactivity and anti-photocorrosion of RGO–Ag2 O/TiO2 composites can be attributed to the following: (i) RGO can serve as a charge transmission bridge between Ag2 O and TiO2, and the Z-scheme keeps the electrons with high reducing capability in the conduction band (CB) of TiO2 and the holes with high oxidation capability in the valence band (VB) of Ag2 O; (ii) Ag2 O NPs are well photodeposited on the surface of RGO and increase the visible and NIR light absorption via their narrow band gap (1.15 eV); (iii) the Z-scheme electron transport mechanism induced the accumulation of photoinduced holes in the VB of Ag2 O which can protect Ag2 O from photocorrosion. The trapping experiments confirmed that ˙O2 − and h + are the main active species in the photocatalytic degradation of TC.