Selective reductions using visible light photocatalysts of supported gold nanoparticles


Autoria(s): Ke, Xuebin; Zhang, Xingguang; Zhao, Jian; Sarina, Sarina; Barry, John; Zhu, Huai Yong
Data(s)

01/01/2013

Resumo

Photocatalytic synthesis using visible light is a desirable chemical process because of its potential to utilize sunlight. Supported gold nanoparticles (Au-NPs) were found to be efficient photocatalysts and the effects of the supports were identified including CeO2, TiO2, ZrO2, Al2O3, and zeolite Y. In particular Au/CeO2 exhibited the high catalytic activity to reduce nitroaromatics to azo compounds, hydrogenate azobenzene to hydroazobenzene, reduce ketones to alcohols, and deoxygenate epoxides to alkenes at ambient temperatures, under irradiation of visible light (or simulated sunlight). The reac-tive efficiency depends on two primary factors: one is the light adsorption of catalysts and another is the driving ability of catalysts corresponding to the reactants. The light absorption by Au-NPs is due to surface plasmon resonance effect or inter-band electron transition; this is related to the reduction ability of the photocatalysts. Irradiation with shorter wavelengths can excite the conduction electrons in Au-NPs to higher energy levels and as a result, induce reduction with more negative reduction potentials. It is known when irradiated with light the Au-NPs can abstract hydrogen from isopropanol forming Au-H species on the Au-NP surface. Hence, we proposed that the active Au-H species will react with the N=O, N=N, C=O double bonds or epoxide bonds, which are weakened by the interaction with the excited electrons in the Au-NPs, and yield the final reductive products. The reacting power of the Au-H species depends on the energy of the excited electrons in Au-NPs: the higher the electronic energy, the stronger the reduction ability of the Au-H species. This finding demonstrates that we can tune the reduction ability of the photocatalysts by manipulating the irradiation wavelength.

Formato

application/pdf

Identificador

http://eprints.qut.edu.au/56076/

Publicador

RSC Publications

Relação

http://eprints.qut.edu.au/56076/2/56076.pdf

DOI:10.1039/C2GC36542A

Ke, Xuebin, Zhang, Xingguang, Zhao, Jian, Sarina, Sarina, Barry, John, & Zhu, Huai Yong (2013) Selective reductions using visible light photocatalysts of supported gold nanoparticles. Green Chemistry, 15(1), pp. 236-244.

Direitos

Copyright 2013 RSC Publications

Fonte

School of Chemistry, Physics & Mechanical Engineering; Science & Engineering Faculty

Palavras-Chave #030301 Chemical Characterisation of Materials #030601 Catalysis and Mechanisms of Reactions #030602 Chemical Thermodynamics and Energetics #selective reduction #visible light photocatalysis #gold nanoparticles #irradiation wavelength #light intensity
Tipo

Journal Article