Electronic properties and charge transfer phenomena in Pt nanoparticles on γ-Al2O3: size, shape, support, and adsorbate effects

Behafarid, Farzad; Ono, Luis K.; Mostafa, Simón; Croy, Jason R.; Shafai, Ghazal; Hong, Sampyo; Rahman, Talat S.; Bare, Simon R.; Cuenya, Beatriz Roldán

doi:10.1039/c2cp41928a

Cited by 81 publications

(104 citation statements)

References 69 publications

(133 reference statements)

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“…Such single-site catalysts were 10 times more active in crotonaldehyde and cinnamaldehyde production than comparable materials employing conventional (100 m 2 g -1 ) c-alumina, owing to the preferential genesis of higher concentrations of electron-deficient palladium [134,137], due to either pinning at cation vacancies or metal ? support charge transfer [183]. These Pd/meso-Al 2 O 3 catalysts exhibited similar TOFs to their silica counterparts (7,080 and 4,400 h -1 for crotyl and cinnamyl alcohol selox, respectively) [137], consistent with a common active site and reaction mechanism (Fig.…”

Section: Establishing Support Effectssupporting

confidence: 56%

Catalysing sustainable fuel and chemical synthesis

Lee

2014

Appl Petrochem Res

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Concerns over the economics of proven fossil fuel reserves, in concert with government and public acceptance of the anthropogenic origin of rising CO 2 emissions and associated climate change from such combustible carbon, are driving academic and commercial research into new sustainable routes to fuel and chemicals. The quest for such sustainable resources to meet the demands of a rapidly rising global population represents one of this century's grand challenges. Here, we discuss catalytic solutions to the clean synthesis of biodiesel, the most readily implemented and low cost, alternative source of transportation fuels, and oxygenated organic molecules for the manufacture of fine and speciality chemicals to meet future societal demands.

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Section: Establishing Support Effectssupporting

confidence: 56%

Catalysing sustainable fuel and chemical synthesis

Lee

2014

Appl Petrochem Res

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“…In general, this 331 effect is most significant for clusters and particles below 1 nm in size for Pt/γ-Al2O3 [30,57]. The smallest 332 average Pt particle diameter considered in this work is 1.3 nm, and therefore we expect this effect to have a 333 minor contribution to the lower TOF for the small Pt particles in this study.…”

mentioning

confidence: 78%

“…A phenomenon occasionally used to explain particle size effects is the transition from a metallic to a non-329 metallic behavior that occurs when Pt particles become sufficiently small, since the band structure responsible 330 for the metallic character of Pt cannot fully develop for very small particles [30,31,56,57]. In general, this 331 effect is most significant for clusters and particles below 1 nm in size for Pt/γ-Al2O3 [30,57].…”

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confidence: 99%

The Effect of Pt Particle Size on the Oxidation of CO, C3H6, and NO Over Pt/Al2O3 for Diesel Exhaust Aftertreatment

et al. 2017

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8Platinum-based oxidation catalysts applied for diesel exhaust aftertreatment constitute a significant part of 9 system costs. Effective utilization of platinum is therefore relevant to reduce costs while retaining 10 performance. To this end, the influence of Pt particle size on catalytic activity for CO, hydrocarbon, and NO 11 oxidation was studied. 1 wt.% Pt/Al2O3 catalysts were prepared by wet impregnation, drying, and different 12 calcination and thermal treatments, yielding Pt particles with diameters between 1.3 and 18.7 nm, as 13 determined by CO pulse titration and transmission electron microscopy. Activity measurements for CO, C3H6, 14 and NO oxidation showed an optimal Pt particle size with respect to the mass based activity between 2-4 nm 15 for all three reactions. From measured turnover frequencies and site statistics of Pt particles, the reactions 16 appear to be mainly catalyzed by terrace atoms, which are most abundant between 2-4 nm. The decrease in 17 catalytic activity for large Pt particles is therefore due to the diminishing Pt surface area, while the decrease in 18 activity for small particles is due to the lack of terrace atoms required for CO, HC, and NO oxidation.

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“…EXAFS provides structural information on the coordination environment around each component for assessing the alloy formation in terms of coordination number (CN) of M or M′ around PGM. In addition, the Pt L-edge absorption edge peak (or white line) is sensitive to the particles' size, shape, and support type [59,60]. The understanding of how both local and extended atomic coordinating parameters, including structural/ chemical alloying degree, interatomic distances, CNs, and oxophilicity, correlate with the NA catalyst's activity and stability is important for the design of NA catalysts.…”

Section: Structural Characterizations Of Pgm Nanoalloy Catalystsmentioning

confidence: 98%

CO oxidation on supported platinum group metal (PGM) based nanoalloys

et al. 2014

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The oxidation of carbon monoxide is widely investigated for realistic and potential uses in energy production and environmental processes. As a probe reaction to the surface properties, it gives an insight into the relationship between the structure of active phase and catalytic performance. Noble metals alloyed with certain transition metals in the form of a nanoalloy exhibit enhanced catalytic activity for various reactions, especially when simultaneous activation of oxygen and CO is involved. This article highlights some of these insights into nanoalloy catalysts in which platinum group metal (PGM) is alloyed with a second and/or third transition metal (M/M′=Co, Fe, V, Ni, Ir, etc.), for catalytic oxidation of carbon monoxide in a gas phase. Recent studies have provided important insights into how the atomic-scale structures of the nanoalloy catalysts operate synergistically in activating oxygen and maneuvering surface oxygenated species. The exploration of atomic-scale chemical/structural ordering and coordination in correlation with the catalytic oxidation properties based on findings from ex-and in-situ synchrotron X-ray techniques is emphasized; for example, high-energy X-ray diffraction coupled to atomic-pair distribution function and X-ray absorption fine-structure spectroscopic analysis. The understanding of the detailed active sites of the nanoalloys has significant implications for the design of low-cost, active, and durable catalysts for sustainable energy production and environmental processes. nanoalloy catalysts, supported noble metal, carbon monoxide oxidation, synchrotron X-ray

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Electronic properties and charge transfer phenomena in Pt nanoparticles on γ-Al2O3: size, shape, support, and adsorbate effects

Cited by 81 publications

References 69 publications

Catalysing sustainable fuel and chemical synthesis

Catalysing sustainable fuel and chemical synthesis

The Effect of Pt Particle Size on the Oxidation of CO, C3H6, and NO Over Pt/Al2O3 for Diesel Exhaust Aftertreatment

CO oxidation on supported platinum group metal (PGM) based nanoalloys

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