Role of Support鈥揘anoalloy Interactions in the Atomic-Scale Structural and Chemical Ordering for Tuning Catalytic Sites

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• 作者：Lefu Yang ; Shiyao Shan ; Rameshwori Loukrakpam ; Valeri Petkov ; Yang Ren ; Bridgid N. Wanjala ; Mark H. Engelhard ; Jin Luo ; Jun Yin ; Yongsheng Chen ; Chuan-Jian Zhong
• 刊名：The Journal of the American Chemical Society
• 出版年：2012
• 出版时间：September 12, 2012
• 年：2012
• 卷：134
• 期：36
• 页码：15048-15060
• 全文大小：708K
• 年卷期：v.134,no.36(September 12, 2012)
• ISSN：1520-5126

文摘

The understanding of the atomic-scale structural and chemical ordering in supported nanosized alloy particles is fundamental for achieving active catalysts by design. This report shows how such knowledge can be obtained by a combination of techniques including X-ray photoelectron spectroscopy and synchrotron radiation based X-ray fine structure absorption spectroscopy and high-energy X-ray diffraction coupled to atomic pair distribution function analysis, and how the support-nanoalloy interaction influences the catalytic activity of ternary nanoalloy (platinum鈥搉ickel鈥揷obalt) particles on three different supports: carbon, silica, and titania. The reaction of carbon monoxide with oxygen is employed as a probe to the catalytic activity. The thermochemical processing of this ternary composition, in combination with the different support materials, is demonstrated to be capable of fine-tuning the catalytic activity and stability. The support-nanoalloy interaction is shown to influence structural and chemical ordering in the nanoparticles, leading to support-tunable active sites on the nanoalloys for oxygen activation in the catalytic oxidation of carbon monoxide. A nickel/cobalt-tuned catalytic site on the surface of nanoalloy is revealed for oxygen activation, which differs from the traditional oxygen-activation sites known for oxide-supported noble metal catalysts. The discovery of such support鈥搉anoalloy interaction-enabled oxygen-activation sites introduces a very promising strategy for designing active catalysts in heterogeneous catalysis.