Hierarchically porous tungstophosphoric acid/silica hybrid for high performance vis-light photocatalysis

• Published in: Journal of environmental chemical engineering 2013-12, Vol.1 (4), p.719-727
• Main Authors: Tao, Shengyang, Wang, Yuchao, Yu, Yongxian, An, Yonglin, Shi, Wenping
• Format: Article
• Language: English
• Subjects: Dye; Hierarchically porous; Photocatalysis
• ISSN: 2213-3437; 2213-3437
• DOI: 10.1016/j.jece.2013.07.012

•Tungstophosphoric acid modified hierarchically porous silica was synthesized.•As-synthesized hierarchically porous silica was used to degrade dye in waste water.•The final material was a green catalyst and no secondary pollutants were generated. A high performance photocatalyst was prepared by loading tungstophosphoric acid (H3PW12O40) in hierarchically porous silica. Several kinds of dye pollutants, such as neutral red, rhodamine B and fuchsin basic, were efficiently degraded under visible light irradiation by this catalyst. The hierarchically porous material was characterized via SEM, FT-IR, N2 adsorption–desorption isotherms and X-ray fluorescence spectrometry (XRF). This kind of photocatalyst had a relative large surface area, pore diameter and pore volume. The degradation kinetics and degradation products were also investigated to clarify the degradation process. The dyes could be facilely and quickly bleached and mineralized (ca. 97.80% of removal for fuchsin basic in 80min), and there were no small organics detected in the main degradation products. Comparing with other porous catalyst carriers (MCM-41 and SBA-15), the hierarchically porous structure was considered to be an important factor to improve the molecular diffusion in the heterocatalysis process and enhance the degradation efficiency. Additionally, this hierarchically porous catalyst was very stable and easy to be separated from the reaction solution for reuse.