Hydrogenation of benzene and toluene over size controlled Pt/SBA-15 catalysts: Elucidation of the Pt particle size effect on reaction kinetics

Пушкарев, В.В.; An, Kwangjin; Alayoǧlu, Selim; Beaumont, Simon K.; Somorjai, Gábor A.

doi:10.1016/j.jcat.2012.04.022

Cited by 123 publications

(65 citation statements)

References 64 publications

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“…Most of the attention has been paid to obtain supported catalysts based on size-controlled NPs in a range of size considered of special interest for catalysis, usually under 10 nm, to assess structure-sensitiveness [36,[38][39][40]. Nevertheless, size-controlled synthesis of catalyst with ranges of NP sizes beyond 10 nm are less studied, in spite of some authors have reported higher activity at the top of their ranges of size studied (%10 nm) [38,41].…”

Section: Introductionmentioning

confidence: 99%

Catalysts based on large size-controlled Pd nanoparticles for aqueous-phase hydrodechlorination

Baeza

Calvo

Rodrı́guez

et al. 2016

Chemical Engineering Journal

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Section: Introductionmentioning

confidence: 99%

Catalysts based on large size-controlled Pd nanoparticles for aqueous-phase hydrodechlorination

Baeza

Calvo

Rodrı́guez

et al. 2016

Chemical Engineering Journal

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“…We also observed fourfold change in turnover rates between nanoparticles of platinum in the 2-to 4-nm range and in the 4-to 6-nm range. The size and shape dependence of nanoparticles can readily be controlled by colloid science technology (36,38,39) (Fig. 1C).…”

Section: Metal Nanoparticles For Size-dependent Covalent Bond Catalysismentioning

confidence: 99%

Molecular catalysis science: Perspective on unifying the fields of catalysis

Hurlburt

Sabyrov

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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Colloidal chemistry is used to control the size, shape, morphology, and composition of metal nanoparticles. Model catalysts as such are applied to catalytic transformations in the three types of catalysts: heterogeneous, homogeneous, and enzymatic. Real-time dynamics of oxidation state, coordination, and bonding of nanoparticle catalysts are put under the microscope using surface techniques such as sumfrequency generation vibrational spectroscopy and ambient pressure X-ray photoelectron spectroscopy under catalytically relevant conditions. It was demonstrated that catalytic behavior and trends are strongly tied to oxidation state, the coordination number and crystallographic orientation of metal sites, and bonding and orientation of surface adsorbates. It was also found that catalytic performance can be tuned by carefully designing and fabricating catalysts from the bottom up. Homogeneous and heterogeneous catalysts, and likely enzymes, behave similarly at the molecular level. Unifying the fields of catalysis is the key to achieving the goal of 100% selectivity in catalysis.Two major breakthroughs have revolutionized molecular catalysis science over the last 20 y. The first is in the development of nanomaterials science (1-4), which has made it possible to synthesize metallic (5-7), bimetallic, and core-shell nanoparticles (8, 9), mesoporous metal oxides (10, 11), and enzymes (12-16) in the nanocatalytic range between 0.8 and 10 nm. The second innovation is in the advancement of spectroscopy and microscopy instruments (17-20)-including nonlinear laser optics (21), sum-frequency generation vibrational spectroscopy (22-24), and synchrotronbased instruments, such as ambient pressure X-ray photoelectron spectroscopy (8,(25)(26)(27), X-ray absorption near-edge structure, extended X-ray absorption fine structure (28-30), infrared (IR) and X-ray microspectroscopies (31), and high-pressure scanning tunneling microscopies (32, 33)-that characterize catalysts at the atomic and molecular levels under reaction conditions (34). Most of the studies that use these techniques focus on nanoscale technologies, such as catalytic energy conversion and information storage, which have reduced the size of transistors to below 25 nm (35).Catalysts are classified into three types-heterogeneous, homogeneous, and enzymatic-and, in most cases, range in size from 1 to 10 nm, which is even smaller than the transistors being developed by the latest size-fabrication technologies. Heterogeneous catalysts work in reaction systems with multiple phases (e.g., solid-gas or solid-liquid phase); homogeneous catalysts reside in the same phase as the reactants, almost always in the liquid phase; and enzymatic catalysts, which are most active in an aqueous solution, make use of active sites in proteins. The catalysis of chemical energy conversion provides ever-increasing selectivity in producing combustible hydrocarbons, gasoline, and diesel.The tenets that direct our catalysis research involve nanoparticle synthesis, characterization under reaction con...

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“…SBA-15 is a mesoporous amorphous silica that has been commonly used as a support for various catalysts. 32,33 It has hexagonally aligned channel-like pores with average pore diameter of 6.4 nm as characterized by TEM and N 2 physisorption. MCF-17 is another amorphous silica with interconnected spherical pores with average diameter of 26.5 nm.…”

Section: Effect Of Catalyst Microstructure and Density Of Acid Sitesmentioning

confidence: 99%

Hydroisomerization of n-hexadecane: remarkable selectivity of mesoporous silica post-synthetically modified with aluminum

Sabyrov

Musselwhite

Melaet

et al. 2017

Catal. Sci. Technol.

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As the impact of acids on catalytically driven chemical transformations is tremendous, fundamental understanding of catalytically relevant factors is essential for the design of more efficient solid acid catalysts. In this work, we employed post-synthetic doping method to synthesize highly selective hydroisomerization catalyst and to demonstrate the effect of acid strength and density, catalyst microstructure, and platinum nanoparticle size on reaction rate and selectivity. Aluminum doped mesoporous silica catalyzed gas-phase n-hexadecane isomerization with remarkably high selectivity, producing substantially higher amount of isomers than traditional zeolite catalysts. The main reason for its high selectivity was found to be mild acidic sites generated by post-synthetic aluminum grafting. The flexibility of post-synthetic doping method enabled us to systematically explore the effect of acid site density on reaction rate and selectivity, which has been extremely difficult to achieve with zeolite catalysts. We found that higher density of Brønsted acid sites leads to higher cracking of n-hexadecane presumably due to increased surface residence time. Furthermore, regardless of pore size and microstructure, hydroisomerization turnover frequency linearly increased as a function of Brønsted acid site density. In addition to strength and density of acid sites, platinum nanoparticle size affected catalytic activity and selectivity. Smallest platinum nanoparticles produced the most effective bifunctional catalyst presumably because of higher percolation into aluminum doped mesoporous silica, generating more 'intimate' metallic and acidic sites. Finally, aluminum doped 2 silica catalyst was shown to retain its remarkable selectivity towards isomers even at increased reaction conversions.

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Hydrogenation of benzene and toluene over size controlled Pt/SBA-15 catalysts: Elucidation of the Pt particle size effect on reaction kinetics

Cited by 123 publications

References 64 publications

Catalysts based on large size-controlled Pd nanoparticles for aqueous-phase hydrodechlorination

Catalysts based on large size-controlled Pd nanoparticles for aqueous-phase hydrodechlorination

Molecular catalysis science: Perspective on unifying the fields of catalysis

Hydroisomerization of n-hexadecane: remarkable selectivity of mesoporous silica post-synthetically modified with aluminum

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