Facet-Dependent Catalytic Activity of Gold Nanocubes, Octahedra, and Rhombic Dodecahedra toward 4-Nitroaniline Reduction

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• 作者：Chun-Ya Chiu ; Pei-Ju Chung ; Ka-Un Lao ; Ching-Wen Liao ; Michael H. Huang
• 刊名：The Journal of Physical Chemistry C
• 出版年：2012
• 出版时间：November 8, 2012
• 年：2012
• 卷：116
• 期：44
• 页码：23757-23763
• 全文大小：494K
• 年卷期：v.116,no.44(November 8, 2012)
• ISSN：1932-7455

文摘

In this study, cubic, octahedral, and rhombic dodecahedral gold nanocrystals synthesized by a seed-mediated growth method were employed as catalysts for the examination of facet-dependent catalytic activity toward NaBH₄ reduction of p-nitroaniline to p-phenylenediamine at different temperatures. Different amounts of the nanocrystal solutions were used so that all samples contain particles with the same total surface area. UV鈥搗is absorption spectra monitored the reaction progress. Rhombic dodecahedra showed the best catalytic efficiency at all the temperatures examined. Nanocubes have higher reaction rates than those of octahedra from 25 to 36 掳C, so the catalytic activity for the reduction reaction follows the order of {110} > {100} > {111}. However, the reaction rates for octahedra increase rapidly with rising temperature; their reaction rate surpasses that for the nanocubes at 40 掳C. Rate constants and activation energies were determined, again showing that the activation energy is lowest for rhombic dodecahedra. Density functional theory (DFT) calculations indicate highest binding energy between p-nitroaniline and the Au(110) plane. The results reveal rhombic dodecahedral gold nanocrystals as highly efficient catalysts.