Promotion of Phenol Photodecomposition over TiO2 Using Au, Pd, and Au鈥揚d Nanoparticles

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• 作者：Ren Su ; Ramchandra Tiruvalam ; Qian He ; Nikolaos Dimitratos ; Lokesh Kesavan ; Ceri Hammond ; Jose Antonio Lopez-Sanchez ; Ralf Bechstein ; Christopher J. Kiely ; Graham J. Hutchings ; Flemming Besenbacher
• 刊名：ACS Nano
• 出版年：2012
• 出版时间：July 24, 2012
• 年：2012
• 卷：6
• 期：7
• 页码：6284-6292
• 全文大小：582K
• 年卷期：v.6,no.7(July 24, 2012)
• ISSN：1936-086X

文摘

Noble metal nanoparticles (Au, Pd, Au鈥揚d alloys) with a narrow size distribution supported on nanocrystalline TiO₂ (M/TiO₂) have been synthesized via a sol-immobilization route. The effect of metal identity and size on the photocatalytic performance of M/TiO₂ has been systematically investigated using phenol as a probe molecule. A different phenol degradation pathway was observed when using M/TiO₂ catalysts as compared to pristine TiO₂. We propose a mechanism to illustrate how the noble metal nanoparticles enhance the efficiency of phenol decomposition based on photoreduction of p-benzoquinone under anaerobic conditions. Our results suggest that the metal nanoparticles not only play a role in capturing photogenerated electrons, but are strongly involved in the photocatalytic reaction mechanism. The analysis of the reaction intermediates allows us to conclude that on M/TiO₂ undesired redox reactions that consume photogenerated radicals are effectively suppressed. The analysis of the final products shows that the reusability performance of the catalyst is largely dependent on the pretreatment of the catalyst and the identity of the metal nanoparticle. Interestingly, the as-prepared Pd and Au鈥揚d decorated TiO₂ materials exhibit excellent long-term photoactivity, in which 90% of the phenol can be fully decomposed to CO₂ in each cycle.

Keywords:

photocatalysis; TiO₂; Au; Pd; Au鈭扨d alloys; phenol decomposition mechanism; reusability; CO₂ conversion