Synthesis and catalytic performance of gold-loaded TiO 2 nanofibers
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Catalysis Letters, Vol. 118, Nos. 1–2, October 2007 (Ó 2007) DOI: 10.1007/s10562-007-9139-0
Synthesis and catalytic performance of gold-loaded TiO2 nanofibers Baolin Zhu, Kairong Li, Yunfeng Feng, Shoumin Zhang, Shihua Wu, and Weiping Huang* Department of Chemistry, Nankai University, Tianjin, 300071, China
Received 15 April 2007; accepted 7 May 2007
By using titanate nanotubes and HAuCl4 as precursor, gold-loaded TiO2 nanofibers (Au/TiO2NFs) are obtained after deposition-photodecomposition process, and the tubular supports are broken after the fabrication process. Catalytic performance of the obtained Au/TiO2NFs is evaluated for low-temperature CO oxidation and photodegradation of methyl orange under UV illumination, and the relationship between the catalytic activity and calcination treatment is investigated. After the Au/TiO2NFs are calcined, their catalytic activity for CO oxidation is enhanced, while the photocatalytic activity decreases. KEY WORDS: gold; TiO2 nanofibers; catalytic activity; CO oxidation; photodegradation.
1. Introduction Gold has been generally regarded as an inert metal until its surprisingly high activity for low-temperature CO oxidation is reported by Haruta and co-workers [1]. Following this work, highly-dispersed gold nanoparticles has been explored to be active in several reactions, including CO oxidation, propylene epoxidation, methanol synthesis, water gas shift reaction, preferential oxidation of CO in the presence of excess hydrogen, environmental catalysis (NOx reduction), hydrogenation reactions, etc. [2]. For supported gold catalysts, different supports have been intensively researched, and their cooperative effects with gold particles are also investigated [3–5]. Among them, TiO2 is a prominent one owing to its low-cost, innocuity, and stability [6]. Recent investigations on gold–TiO2 nanocomposite also show that gold-doping enhances the photocatalytic activity and extends the response of the TiO2 catalyst into visible region [7]. It has been well established that the catalytic properties of Au–TiO2 system depends not only on the size of the Au clusters, the preparation method, but also the support [8]. TiO2 nanotube, which has large surface area, should be a better support than common TiO2 powder. In 1998, Kasuga developed a hydrothermal method to turn TiO2 powders into tubular structure in 10 M NaOH solution [9]. In our earlier work, gold particles are loaded on this kind of nanotubes by deposition-precipitation method [10], and CuO-modified ones are prepared by impregnation method [11]. All of the prepared catalysts exhibit high catalytic activity for low-temperature CO oxidation after a calcinations process [10,11], which indicates the application potential *To whom correspondence should be addressed. E-mail: [email protected]
of TiO2 nanotubes in the catalyst field. In this letter, gold particles are loaded on titanate nanotubes by deposition-photodecomposition method. Their catalytic activity for CO oxidation and photodegradation of methyl orange is evaluated.
2. Experimental
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