Coupling of W-Doped SnO 2 and TiO 2 for Efficient Visible-Light Photocatalysis

• Published in: Bulletin of the Korean Chemical Society Vol. 35; no. 3; pp. 913 - 918
• Main Authors: Rawal, Sher Bahadur, Ojha, Devi Prashad, Choi, Young Sik, Lee, Wan In
• Format: Journal Article
• Language: Korean
• Published: 2014
• Subjects: Tungsten-doped tin oxide; W_xSn_{1-x}O_2/TiO_2; Visible-light; Photocatalyst; Heterojunction
• ISSN: 0253-2964; 1229-5949

Five mol % tungsten-doped tin oxide ($W_{0.05}Sn_{0.95}O_2$, TTO5) was prepared by co-precipitation of $SnCl_4{\cdot}5H_2O$ and $WCl_4$, followed by calcination at $1000^{\circ}C$. The as-prepared TTO5 was in the pure cassiterite phase with a particle size of ~50 nm and optical bandgap of 2.51 eV. Herein it was applied for the formation of TTO5/$TiO_2$ heterojunctions by covering the TTO5 surface with $TiO_2$ by sol-gel method. Under visible-light irradiation (${\lambda}{\geq}420$ nm), TTO5/$TiO_2$ showed a significantly high photocatalytic activity in removing gaseous 2-propanol (IP) and evolving $CO_2$. It is deduced that its high visible-light activity is caused by inter-semiconductor holetransfer between the valence band (VB) of TTO5 and $TiO_2$, since the TTO5 nanoparticle (NP) exhibits the absorption edge at ~450 nm and its VB level is located more positive side than that of $TiO_2$. The evidence for the hole-transport mechanism between TTO5 and $TiO_2$ was also investigated by monitoring the holescavenging reaction with 1,4-terephthalic acid (TA).