Plasmonic TiO2/AgBr/Ag ternary composite nanosphere with heterojunction structure for advanced visible light photocatalyst

• Published in: Applied surface science 2014-09, Vol.314, p.864-871
• Main Authors: Dai, Kai, Li, Dongpei, Lu, Luhua, Liu, Qi, Liang, Changhao, Lv, Jiali, Zhu, Guangping
• Format: Article
• Language: English
• Subjects: AgBr; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Construction; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Light absorption; Methylene blue; Nanostructure; Photocatalysis; Photocatalytic activity; Physics; Plasmonics; Scanning electron microscopy; Silver; TiO2; Titanium dioxide
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2014.06.183

•TiO2/AgBr/Ag ternary composite nanosphere was prepared.•TiO2/AgBr/Ag showed high photocatalytic activity with irradiation of LED light.•TiO2/AgBr/Ag exhibited high stability. In this work, TiO2/AgBr/Ag ternary composite nanosphere photocatalyst has been synthesized by in situ deposition of AgBr onto hollow spherical TiO2 template and followed by sun light reduction of AgBr into AgBr/Ag. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images have shown that the diameter of hollow TiO2 nanospheres is 250–350nm and AgBr/Ag nanoparticles are well dispersed on the outer surface of TiO2 nanosphere. UV–vis spectrum analysis has shown largely improved visible light absorption of this ternary composite, in comparison to pure TiO2 and AgBr. The building-in AgBr/Ag, TiO2/AgBr and TiO2/Ag junctions within the ternary composite enhanced the visible light absorption because of plasmonic resonance and narrow bandgap. The pseudo-first-order rate constant kapp of the TiO2/AgBr/Ag ternary composite for methylene blue photodegradation displays 24.5 times and 3.3 times than the pure TiO2 nanosphere and AgBr/Ag nanoparticles, respectively. Furthermore, the stability of TiO2/AgBr/Ag ternary composite is characterized through cyclic photocatalytic test. Results indicate that 92.7% of photocatalytic degradation can be achieved by TiO2/AgBr/Ag ternary composite even after five recycles.