Sum Frequency Generation Vibrational Spectroscopy and Kinetic Study of 2-Methylfuran and 2,5-Dimethylfuran Hydrogenation over 7 nm Platinum Cubic Nanoparticles

Aliaga, César; Tsung, Chia‐Kuang; Alayoǧlu, Selim; Komvopoulos, K.; Yang, Peidong; Somorjai, Gábor A.

doi:10.1021/jp111343j

Cited by 37 publications

(32 citation statements)

References 27 publications

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“…Recently, several studies focused on the catalytic properties of Pt nanoparticles with different shapes and sizes [11][12][13][14][15][16][17][18]. Alayoglu et al [14] showed that the turnover frequency of the ethylene hydrogenation reaction is insensitive to the size of the Pt nanoparticles in the range of 1-11 nm.…”

Section: Introductionmentioning

confidence: 99%

Recovery of Pt Surfaces for Ethylene Hydrogenation-Based Active Site Determination

et al. 2014

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The effect of pretreatment (O 2 or H 2) and catalyst history was investigated through room temperature ethylene hydrogenation reaction over several types of platinum based nanoparticle systems: 1.6 nm Pt/TTAB, 4.1 nm Pt/PVP (with and without UV treatment), 4.1 nm Pt with a silica shell, and e-beam evaporated Pt thin films were tested. The H 2 pretreatment resulted in the absence of activity. However, Pt active sites for the ethylene hydrogenation reaction were recovered after an O 2 pretreatment irrespective of the catalyst history, regardless of the particle size nor the presence, absence or type of capping agent. The calculation of the average TOF resulted in 10.13 ± 3.27. This value correlates well with data from the literature. Thus, the ethylene hydrogenation reaction can be used to determine available sites of Pt catalysts if the reaction is following an O 2 pretreatment.

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Section: Introductionmentioning

confidence: 99%

Recovery of Pt Surfaces for Ethylene Hydrogenation-Based Active Site Determination

et al. 2014

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“…Recent studies have shed some light onto the nature of these transformations teps on Pt and Pd surfaces. Thus, Kliewer et al [13] investigated the hydrogenationo ff uran over Pt by using sum frequencyg eneration vibrational spectroscopy (SFGVS).T hey observed that the planar furan ring lay flat on all Pt surfaces investigated, whereas both THF and butanol (as butoxy) product speciesw ere bound through the Oa tom in an upright geometry.A liaga et al [14] furtheri nvestigated the hydrogenation of 2-methylfuran and 2,5-dimethylfurana t2 0-120 8Co ver 7nmc ubic Pt nanoparticles that resulted in linear alcohols as the dominant hydrogenation products under these low-temperature conditions. SFGVS further indicated that these alkylfurans lay flat on the Pt surface, whereas the corresponding THFs and alcohol speciesw ere adsorbed in an upright position through the O atoms.…”

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confidence: 99%

Deuterium‐Labeling Study of the Hydrogenation of 2‐Methylfuran and 2,5‐Dimethylfuran over Carbon‐Supported Noble Metal Catalysts

2015

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2-Methylfuran and 2,5-dimethylfuran were deuterated over Pd and Pt catalysts at 90-220 °C. Furan ring saturation over a Pd/C catalyst occurred at low reaction temperatures, which led to deuterated THFs, followed by progressive D exchange in the THF ring at higher temperatures. Finally, H/D exchange occurred in the methyl groups on the THF ring. Cleavage of the C-O bond also occurred over a Pd/C catalyst at elevated temperatures, which resulted in deuterated ketones, for which all H atoms were exchanged for D. Alcohols were produced over a Pt/C catalyst at low temperatures because they are more stable than the corresponding ketones. D replaced H on all carbon atoms of the furan ring and saturated the O and C atoms of the broken C-O bond in both deuterated 2-pentanol and 2-hexanol. At low temperatures (90-105 °C), all H atoms in the deuterated alcohols were exchanged for D except for the last two hydrogen atoms on the methyl groups.

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“…Short attenuation lengths of the evanescent waves, on the order of tens of nanometers, limit the probed area to near surface regions of the sample, either in contact with the prism [36] (Fig. 5) or across an ultrathin layer of aqueous electrolyte [37] that separates the sample and prism.…”

Section: Surface Orientation and Molecular Bonding Via Vibrational Spmentioning

confidence: 99%

Nanocatalysis II: In Situ Surface Probes of Nano-Catalysts and Correlative Structure–Reactivity Studies

Alayoǧlu

Somorjai

2014

Catal Lett

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Model nano-catalysts with monodisperse particle sizes and architectures are essential for a fundamental understanding of surface property dynamics during catalytic reactions. Surface tools and techniques, when conducted under catalytically relevant temperature and pressure conditions, render possible measurements of dynamic surface properties such as oxidation state, composition, coordination, and bonding. Near edge X-ray absorption fine structure (NEXAFS) spectroscopy with purposely built in situ reaction cells and ambient pressure X-ray photoelectron spectroscopy (APXPS) provide (near) surface sensitive and chemical specific information on the oxidation states of metal and oxide (co-)catalysts as well as adsorbent functional elements such C, O and N under reactive gas atmospheres and even liquid environments. Likewise, sum frequency generation (SFG) vibrational spectroscopy with in situ reaction cells helps uncover the bonding geometry and configuration of the topmost surface again under conditions pertinent to catalysis. Furthermore, the local dynamics in the nanoscale and on the single particle level are revealed by environmental transmission electron microscopy (ETEM) and the spectro-microscopy techniques equipped within. A correlative approach, where an array of these in situ tools and techniques were conducted in parallel with catalytic measurements, was employed to gain molecular insight into some of the modern scientific challenges in heterogeneous catalysis.Several case examples of this correlative approach are presented here. The CO oxidation reaction over hybrid nano-catalysts of Pt nanoparticles (NPs) with various mesoporous metal oxides such as Co 3 O 4 , MnO 2 and CeO 2 was explored in relation to bifunctional catalysis and interfacial charge transfer chemistry by using in situ NEXAFS spectroscopy. Likewise, bimetallic CoPt and PtSn nanoparticle catalysts supported on silica were investigated by using a combination of in situ NEXAFS spectroscopy and APXPS. Next, CO 2 hydrogenation was carried out over bimetallic CoPt/SiO 2 and Co/TiO 2 hybrid nano-catalysts. In this case, in situ NEXAFS spectroscopy, APXPS, and ETEM indicated severe, yet reversible, surface restructuring that involved hydrogen atom spillover. Finally, *2 nm Pt NPs were investigated using in situ SFG to study hydrogenation and hydrogenative isomerization reactions. Specifically, SFG indicated that the hydrogenation of furfural and crotonaldehyde proceed by interfacial hydrogen atom spillover from TiO 2 , while the hydrogenative isomerization of methylcyclopentane (MCP) proceeds by spillover and surface diffusion of cyclohexene over mesoporous zeolites. These studies unequivocally indicated the presence of a particular reaction channel that involved one way flow of charged (i.e. electrons or protons) or neutral species (i.e. reactants) at a broadly defined interface between metals and oxides. In addition to these case studies, experimental approaches employing capillary flow micro-reactors are discussed in relation toward t...

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Sum Frequency Generation Vibrational Spectroscopy and Kinetic Study of 2-Methylfuran and 2,5-Dimethylfuran Hydrogenation over 7 nm Platinum Cubic Nanoparticles

Cited by 37 publications

References 27 publications

Recovery of Pt Surfaces for Ethylene Hydrogenation-Based Active Site Determination

Recovery of Pt Surfaces for Ethylene Hydrogenation-Based Active Site Determination

Deuterium‐Labeling Study of the Hydrogenation of 2‐Methylfuran and 2,5‐Dimethylfuran over Carbon‐Supported Noble Metal Catalysts

Nanocatalysis II: In Situ Surface Probes of Nano-Catalysts and Correlative Structure–Reactivity Studies

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