Large-scale synthesis and enhanced visible-light-driven photocatalytic performance of hierarchical Ag/AgCl nanocrystals derived from freeze-dried PVPaAg+ hybrid precursors with porosity

• Published in: Applied catalysis. B, Environmental Vol. 144; pp. 394 - 407
• Main Authors: Chen, Deliang, Liu, Minna, Chen, Qianqian, Ge, Lianfang, Fan, Bingbing, Wang, Hailong, Lu, Hongxia, Yang, Daoyuan, Zhang, Rui, Yan, Qishe, Shao, Guosheng, Sun, Jing, Gao, Lian
• Format: Journal Article
• Language: English
• Published: 01.01.2014
• Subjects: Isopropanol; Methyl alcohol; Nanocrystals; Photocatalysis; Photocatalysts; Photodegradation; Silver; Titanium dioxide
• ISSN: 0926-3373
• DOI: 10.1016/j.apcatb.2013.07.042

To achieve high-performance, hierarchical plasmonic Ag/AgCl photocatalysts, a freeze-drying route was developed to form porous PVPaAg+ hybrid compounds, which were then transformed to hierarchical Ag/AgCl nanocrystals through a liquid-solid precipitation reaction followed by a partially photoreduction under ambient conditions. The PVPaAg+ hybrid precursors and their final Ag/AgCl nanocrystals obtained were characterized by various techniques. The hierarchical Ag/AgCl nanocrystals obtained had an apparent size range of 156 A- 50 nm, and the surfaces of the large particles were covered with small nanocrystals with sizes of 33 A- 12 nm. The photocatalytic performance of the hierarchical Ag/AgCl nanocrystals was estimated by degradating organic dyes (i.e., RhB, MO, and MB) and alcohols (i.e., methanol and isopropanol) under visible light (I> aY 420 nm) and sunlight. The results indicated that the hierarchical Ag/AgCl nanocrystals obtained were efficient visible-light-driven photocatalysts in decomposing organic dyes, and their RhB photodegradation rates (a140.97 mina1) was a1454 times higher than that (a140.018 mina1) of TiO2 (P25) nanocrystals under the same visible-light conditions. The photodegradation efficiency of methanol and isopropanol reached a1445% and 35%, respectively, after visible-light irradiation for 60 min according to the COD data. The enhancement in visible-light-driven photodegradation performance results from the high absorbance through 350a800 nm due to the SPR effect of metal Ag species embedded in the hierarchical AgCl host nanocrystals. The influencing factors and possible growth mechanism of the Ag/AgCl nanocrystals were investigated, and the PVP molecules and the freeze-drying process were highly influenced the size and morphology of Ag/AgCl nanocrystals. The outstanding advantage of the freeze-drying assisted route is its ability in large-scale synthesis of hierarchical Ag/AgCl nanocrystals.