Influence of Particle Size on Reaction Selectivity in Cyclohexene Hydrogenation and Dehydrogenation over Silica-Supported Monodisperse Pt Particles

Rioux, R.M.; Hsu, B.F.; Grass, ME; Song, Hyunjoon; Somorjai, G.A.

doi:10.1007/s10562-008-9637-8

Cited by 79 publications

(82 citation statements)

References 39 publications

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“…It was also reported that cyclohexene exclusively dehydrogenates to benzene (i.e. no hydrogenation to cyclohexane) at 1 atm and temperatures above 240°C in H 2 partial pressures up to 500 torr [31]. This explains as to why no cyclohexane (or cyclohexenes) was observed for any of our nanoparticle catalysts.…”

Section: Mcp/h 2 Reaction Over Monodisperse Pt Npsupporting

confidence: 60%

Size and Shape Dependence on Pt Nanoparticles for the Methylcyclopentane/Hydrogen Ring Opening/Ring Enlargement Reaction

et al. 2011

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Monodisperse Pt nanoparticles (NPs) with well-controlled sizes in the range between 1.5 and 10.8 nm, and shapes of octahedron, cube, truncated octahedron and spheres (*6 nm) were synthesized employing the polyol reduction strategy with polyvinylpyrrolidone (PVP) as the capping agent. We characterized the as-synthesized Pt nanoparticles using transmission electron microscopy (TEM), high resolution TEM, sum frequency generation vibrational spectroscopy (SFGVS) using ethylene/H 2 reaction as the surface probe, and the catalytic ethylene/H 2 reaction by means of measuring surface concentration of Pt. The nanoparticles were supported in mesoporous silica (SBA-15 or MCF-17), and their catalytic reactivity was evaluated for the methylcyclopentane (MCP)/H 2 ring opening/ring enlargement reaction using 10 torr MCP and 50 torr H 2 at temperatures between 160 and 300°C. We found a strong correlation between the particle shape and the catalytic activity and product distribution for the MCP/ H 2 reaction on Pt. At temperatures below 240°C, 6.3 nm Pt octahedra yielded hexane, 6.2 nm Pt truncated octahedra and 5.2 nm Pt spheres produced 2-methylpentane. In contrast, 6.8 nm Pt cubes led to the formation of cracking products (i.e. C 1 -C 5 ) under similar conditions. We also detected a weak size dependence of the catalytic activity and selectivity for the MCP/H 2 reaction on Pt. 1.5 nm Pt particles produced 2-methylpentane for the whole temperature range studied and the larger Pt NPs produced mainly benzene at temperatures above 240°C.

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Section: Mcp/h 2 Reaction Over Monodisperse Pt Npsupporting

confidence: 60%

Size and Shape Dependence on Pt Nanoparticles for the Methylcyclopentane/Hydrogen Ring Opening/Ring Enlargement Reaction

et al. 2011

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“…The size of nanoparticles influences not only the reaction rate but also the product selectivity. Many hydrogenation reactions of small molecules including pyrrole [53], furan [54], crotonaldehyde [55], butadiene [56], furfural [57], methylcyclopentane [58], cyclohexene [59], and nhexane [60] have been proven to change their selectivity by Pt nanoparticle size or shape. For example, in 1,3-butadiene hydrogenation, 0.9 and 1.8 nm Pt nanoparticles increased the production of n-butane by full hydrogenation, whereas 4.6 and 6.7 nm Pt catalysts favored 1-butene by partial hydrogenation [56].…”

Section: Size-and Shape-dependent Catalytic Propertiesmentioning

confidence: 99%

Nanocatalysis I: Synthesis of Metal and Bimetallic Nanoparticles and Porous Oxides and Their Catalytic Reaction Studies

Somorjai

2014

Catal Lett

133

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In recent heterogeneous catalysis, much effort has been made in understanding how the size, shape, and composition of nanoparticles and oxide-metal interfaces affect catalytic performance at the molecular level. Recent advances in colloidal synthetic techniques enable preparing diverse metallic or bimetallic nanoparticles with welldefined size, shape, and composition and porous oxides as a high surface support. As nanoparticles become smaller, new chemical, physical, and catalytic properties emerge. Geometrically, as the smaller the nanoparticle the greater the relative number of edge and corner sites per unit surface of the nanoparticle. When the nanoparticles are smaller than a critical size (2.7 nm), finite-size effects such as a change of adsorption strength or oxidation state are revealed by changes in their electronic structures. By alloying two metals, the formation of heteroatom bonds and geometric effects such as strain due to the change of metal-metal bond lengths cause new electronic structures to appear in bimetallic nanoparticles. Ceaseless catalytic reaction studies have been discovered that the highest reaction yields, product selectivity, and process stability were achieved by determining the critical size, shape, and composition of nanoparticles and by choosing the appropriate oxide support. Depending on the pore size, various kinds of micro-, meso-, and macro-porous materials are fabricated by the aid of structure-directing agents or hardtemplates. Recent achievements for the preparation of versatile core/shell nanostructures composing mesoporous oxides, zeolites, and metal organic frameworks provide new insights toward nanocatalysis with novel ideas.

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“…24 It has been well known that the activity and selectivity of many structure sensitive catalytic reactions can be optimized by changing the size and shape of supported metal catalysts. 23,[25][26][27] Inspired by reported experimental work of furfural HDO over supported Pt catalysts, 11 we investigated the effect of surface structure on the selectivity of furfural HDO over Pt catalysts. Unlike the previous theoretical modeling of furfural reaction using DFT calculations in which only flat (111) structure was investigated, three model Pt surfaces, that is, periodic Pt(111) and Pt(211) surfaces, as well as Pt 55 cluster were used.…”

Section: Introductionmentioning

confidence: 99%

Mechanistic insights into the structure‐dependent selectivity of catalytic furfural conversion on platinum catalysts

Cai

Wang

et al. 2015

AIChE Journal

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The effects of surface structures on the selectivity of catalytic furfural conversion over platinum (Pt) catalysts in the presence of hydrogen have been studied using first principles density functional theory (DFT) calculations and microkinetic modeling. Three Pt model surface structures, that is, flat Pt(111), stepped Pt(211), and Pt 55 cluster are chosen to represent the terrace, step, and corner sites of Pt nanoparticle. DFT results show that the dominant reaction route (hydrogenation or decarbonylation) in furfural conversion depends strongly on the structures (or reactive sites). Using the size-dependent site distribution rule, our microkinetic modeling results indicate the decarbonylation route prevails over smaller Pt particles less than 1.4 nm while the hydrogenation is the dominant reaction route over larger Pt catalyst particles at T 5 473 K and P H 2 5 93 kPa. This is in good agreement with the reported experimental observations.

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Influence of Particle Size on Reaction Selectivity in Cyclohexene Hydrogenation and Dehydrogenation over Silica-Supported Monodisperse Pt Particles

Cited by 79 publications

References 39 publications

Size and Shape Dependence on Pt Nanoparticles for the Methylcyclopentane/Hydrogen Ring Opening/Ring Enlargement Reaction

Size and Shape Dependence on Pt Nanoparticles for the Methylcyclopentane/Hydrogen Ring Opening/Ring Enlargement Reaction

Nanocatalysis I: Synthesis of Metal and Bimetallic Nanoparticles and Porous Oxides and Their Catalytic Reaction Studies

Mechanistic insights into the structure‐dependent selectivity of catalytic furfural conversion on platinum catalysts

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