Ethanol Reactions over the Surfaces of Noble Metal/Cerium Oxide Catalysts

Idriss, Hicham

doi:10.1595/147106704x1603

Cited by 226 publications

(175 citation statements)

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“…A possible reason for this difference could be the specific interaction between the small palladium crystals and the surrounding ceria which can favor the stabilization of the metal [30][31][32][33][34]. Possible implications of this strong metal support interaction (SMSI) in the studied reaction have actually been investigated in a more detailed study.…”

Section: Phenol Oxidation With Catalytic Membrane Reactors Prepared Bmentioning

confidence: 99%

Heterogeneous catalytic oxidation of phenol by in situ generated hydrogen peroxide applying novel catalytic membrane reactors

Osegueda

Dafinov

Llorca

et al. 2015

Chemical Engineering Journal

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This work presents a novel method for oxidation of organic matter in water solutions based on catalytic membrane reactors. The oxidant, hydrogen peroxide, is generated directly in the bulk of the liquid investigated. Commercial symmetric alumina hollow fibers have been used as a starting material thereafter introducing the active phases. It has been proven that two different catalysts are necessary in order to complete the overall reaction, as well as to generate hydrogen peroxide and a heterogeneous Fenton process. Palladium has been used for the hydrogen peroxide generation and a second active phase, transitional metal oxides or homogeneous Fe2+, has been used for the hydroxyl radical generation. An additional method for specific Pd loading to the reaction zone based on sputtering technique has been developed. All prepared catalytic membrane reactors (CMRs) are capable of generating hydrogen peroxide in amounts comparable to CMRs reported in the literature. The catalytic membrane reactors prepared by Pd impregnation show very high activity and stability in phenol oxidation reaching 40% of the generated H2O2 usage in the oxidation reaction. Despite the very high activity of the catalytic membrane reactors obtained by Pd sputtering in H2O2 production they suffer very fast deactivation. Specific reactivation including a calcination step has been found to be appropriate for the recovery of their activity. Additional experiments give new insights for better understanding of Pd deactivation especially when the metal particles are of nanometer sizes. (C) 2014 Elsevier B.V. All rights reserved.Postprint (published version

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Section: Phenol Oxidation With Catalytic Membrane Reactors Prepared Bmentioning

confidence: 99%

Heterogeneous catalytic oxidation of phenol by in situ generated hydrogen peroxide applying novel catalytic membrane reactors

Osegueda

Dafinov

Llorca

et al. 2015

Chemical Engineering Journal

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“…Ethanol activation pathways depend on the metal nature, and can be generally divided in two groups: the less-oxophilic metals (Pd and Pt) in which α-C-H activation takes place, and the more-oxophilic metals (Co, Ni, Rh, Ru) that promote activation via O-H. Despite its higher cost, noble metals are the best catalyst candidates for SRE due to their greater ability to break C-C bonds, requiring less active metal loading compared to non-noble metals [26]. system by the use of an elevated gas hourly space velocity (GHSV) [39].…”

Section: Introductionmentioning

confidence: 99%

Hydrogen Production by Steam Reforming of Ethanol on Rh-Pt Catalysts: Influence of CeO2, ZrO2, and La2O3 as Supports

et al. 2015

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CeO2-, ZrO2-, and La2O3-supported Rh-Pt catalysts were tested to assess their ability to catalyze the steam reforming of ethanol (SRE) for H2 production. SRE activity tests were performed using EtOH:H2O:N2 (molar ratio 1:3:51) at a gaseous space velocity of 70,600 h −1 between 400 and 700 °C at atmospheric pressure. The SRE stability of the catalysts was tested at 700 °C for 27 h time on stream under the same conditions. RhPt/CeO2, which showed the best performance in the stability test, also produced the highest H2 yield above 600 °C, followed by RhPt/La2O3 and RhPt/ZrO2. The fresh and aged catalysts were characterized by TEM, XPS, and TGA. The higher H2 selectivity of RhPt/CeO2 was ascribed to the formation of small (~5 nm) and stable particles probably consistent of Rh-Pt alloys with a Pt surface enrichment. Both metals were oxidized and acted as an almost constant active phase during the stability test owing to strong metal-support interactions, as well as the superior oxygen mobility of the support. The TGA results confirmed the absence of carbonaceous residues in all the aged catalysts.

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“…Upon normalisation of the H 2 rate with respect to the surface areas of the TiO 2 nano-and micro-particles, it was found that both particle sizes yielded similar specific reaction rates, indicating that support particle size is not an important parameter for Au/TiO 2 photocatalysis. Infrared spectroscopy (IR) of the ethanol exposed Au/TiO 2 surface showed deprotonation of ethanol upon ethanol adsorption on the Au/TiO 2 surface, similar to most metal/metal oxides systems [29,30]. Combining the IR data with the desorption profile gained from temperature programmed desorption (TPD), which showed the main reaction to be that of dehydrogenation of ethanol to form acetaldehyde, Nadeem et al [28] put forward the following reaction pathway for the photoreaction of ethanol over the Au/TiO 2 surface as shown in Eqs.…”

Section: Au/tio 2 Nanoparticlesmentioning

confidence: 80%

Photoreaction of Au/TiO2 for hydrogen production from renewables: a review on the synergistic effect between anatase and rutile phases of TiO2

Connelly

Ahmed

Idriss

2012

Mater Renew Sustain Energy

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The review focus is on hydrogen production from renewables using photocatalysis. In particular we focus on the role of synergism on the reaction rate. Among the most studied examples for this phenomenon are catalysts based on TiO 2 . TiO 2 exists in two common phases: anatase and rutile, with the latter more thermodynamically stable. For hydrogen production the photocatalyst is often composed of nano-size precious metals deposited on TiO 2 (such as Pt, Pd, or Au). It has been observed by many researchers over a decade that M/TiO 2 rutile is far less active than M/TiO 2 anatase. Yet, the presence of the two phases together results in considerable enhancement of the reaction rate when compared to M/TiO 2 anatase alone. The main reason for this is the increase of the charge carriers' lifetime allowing for electron transfer to hydrogen ions and hole transfer to oxygen ions (and/or the sacrificial agent used). In this work we review the few proposed models, so far, explaining the way by which this charge transfer occurs across both phases.

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Ethanol Reactions over the Surfaces of Noble Metal/Cerium Oxide Catalysts

Cited by 226 publications

References 0 publications

Heterogeneous catalytic oxidation of phenol by in situ generated hydrogen peroxide applying novel catalytic membrane reactors

Heterogeneous catalytic oxidation of phenol by in situ generated hydrogen peroxide applying novel catalytic membrane reactors

Hydrogen Production by Steam Reforming of Ethanol on Rh-Pt Catalysts: Influence of CeO2, ZrO2, and La2O3 as Supports

Photoreaction of Au/TiO2 for hydrogen production from renewables: a review on the synergistic effect between anatase and rutile phases of TiO2

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