Colloidally Synthesized Monodisperse Rh Nanoparticles Supported on   SBA-15 for Size- and Pretreatment-Dependent Studies of CO Oxidation

doi:10.1021/jp901288m

CORC > 北京大学 > 化学与分子工程学院

	Colloidally Synthesized Monodisperse Rh Nanoparticles Supported on SBA-15 for Size- and Pretreatment-Dependent Studies of CO Oxidation
	Grass, Michael E. ; Joo, Sang Hoon ; Zhang, Yawen ; Somorjai, Gabor A.
刊名	journal of physical chemistry c
	2009
关键词	PLATINUM NANOPARTICLES CARBON-MONOXIDE RHODIUM NANOPARTICLES CATALYTIC-PROPERTIES AQUEOUS-SOLUTION PALLADIUM NANOPARTICLES INFRARED-SPECTRA SUZUKI REACTIONS MODEL CATALYSTS CHEMISORBED CO
DOI	10.1021/jp901288m
英文摘要	A particle size dependence for CO oxidation over rhodium nanoparticles of 1.9-11.3 nm has been investigated and determined to be modified by the existence of the capping agent poly(vinylpyrrolidone) (PVP). The particles were prepared using a polyol reduction procedure with PVP as the capping agent. The Rh nanoparticles were subsequently supported on SBA-15 during hydrothermal synthesis to produce Rh/SBA-15 supported catalysts for size-dependent catalytic studies. CO oxidation by O(2) at 40 Torr CO and 100 Torr O(2) was investigated over two series of Rh/SBA-15 catalysts: as-synthesized Rh/SBA-15 covering the full range of Rh sizes and the same set of catalysts after high temperature calcination and reduction. The turnover frequency at 443 K increases from 0.4 to 1.7 s(-1) as the particle size decreases from 11.3 to 1.9 nm for the as-synthesized catalysts. After calcination and reduction, the turnover frequency is between 0.1 and 0.4 s(-1) with no particle size dependence. The apparent activation energy for all catalysts is similar to 30 kcal mol(-1) and is independent of particle size and thermal treatment. Infrared spectroscopy of CO on the Rh nanoparticles indicates that the heat treatments used influence the mode of CO adsorption. As a result, the particle size dependence for CO oxidation is altered after calcination and reduction of the catalysts. CO adsorbs at two distinct bridge sites on as-synthesized Rh/SBA-15, attributable to metallic Rh(0) and oxidized Rh(I) bridge sites. After calcination and reduction, however, CO adsorbs only at Rh(0) atop sites. The change in adsorption geometry and oxidation activity may be attributable to the interaction between PVP and the Rh surface. This capping agent affect may open new possibilities for the tailoring of metal catalysts using solution nanoparticle synthesis methods.; Chemistry, Physical; Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; SCI(E); EI; 40; ARTICLE; 20; 8616-8623; 113
语种	英语
内容类型	期刊论文
源URL	[http://ir.pku.edu.cn/handle/20.500.11897/245828]
专题	化学与分子工程学院
推荐引用方式 GB/T 7714	Grass, Michael E.,Joo, Sang Hoon,Zhang, Yawen,et al. Colloidally Synthesized Monodisperse Rh Nanoparticles Supported on SBA-15 for Size- and Pretreatment-Dependent Studies of CO Oxidation[J]. journal of physical chemistry c,2009.
APA	Grass, Michael E.,Joo, Sang Hoon,Zhang, Yawen,&Somorjai, Gabor A..(2009).Colloidally Synthesized Monodisperse Rh Nanoparticles Supported on SBA-15 for Size- and Pretreatment-Dependent Studies of CO Oxidation.journal of physical chemistry c.
MLA	Grass, Michael E.,et al."Colloidally Synthesized Monodisperse Rh Nanoparticles Supported on SBA-15 for Size- and Pretreatment-Dependent Studies of CO Oxidation".journal of physical chemistry c (2009).