Bio-ethanol steam reforming and autothermal reforming in 3-μm channels coated with RhPd/CeO2 for hydrogen generation

Divins, Núria J.; López, Eduardo; Rodríguez, Ángel; Vega, Davide; Llorca, Jordi

doi:10.1016/j.cep.2012.10.018

Cited by 61 publications

(33 citation statements)

References 23 publications

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“…1. It is clear that in all cases the ESR process takes place to a larger extent when the noble metals are supported on ceria as compared to the bare supports, as reported elsewhere [7,8,10]. It is also evident that higher temperatures favor the reforming process, in accordance with the endothermic character of the reaction.…”

Section: Catalytic Performancesupporting

confidence: 67%

“…The cooperative effect of C C bond cleavage provided by Rh together with hydrogen recombination favored by Pd and the simultaneous dissociation of H 2 O and oxygen mobility provided by CeO 2 results in a highly active, selective and stable multifunctional catalyst for ESR [7]. Thus, RhPd/CeO 2 catalysts have been successfully employed in a catalytic membrane reactor to yield pure hydrogen from ethanol [8] and used in a fuel reformer for direct PEM fuel cell feeding [9] as well as in microdevices using raw bio-ethanol [10]. The fundamental source of this catalytic performance remains poorly understood and is the key to further improving applicability.…”

Section: Introductionmentioning

confidence: 99%

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The influence of nano-architectured CeO supports in RhPd/CeO2 for the catalytic ethanol steam reforming reaction

Divins

Casanovas

et al. 2015

Catalysis Today

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a b s t r a c tThe ethanol steam reforming (ESR) reaction has been tested over RhPd supported on polycrystalline ceria in comparison to structured supports composed of nanoshaped CeO2 cubes and CeO2 rods tailored toward the production of hydrogen. At 650-700 K the hydrogen yield follows the trend RhPd/CeO2 -cubes > RhPd/CeO2 -rods > RhPd/CeO2 -polycrystalline, whereas at temperatures higher than 800 K the catalytic performance of all samples is similar and close to the thermodynamic equilibrium. The improved performance of RhPd/CeO2 -cubes and RhPd/CeO2 -rods for ESR at low temperature is mainly ascribed to higher water-gas shift activity and a strong interaction between the bimetallic-oxide support interaction. STEM analysis shows the existence of RhPd alloyed nanoparticles in all samples, with no apparent relationship between ESR performance and RhPd particle size. X-ray diffraction under operating conditions shows metal reorganization on {1 0 0} and {1 1 0} ceria crystallographic planes during catalyst activation and ESR, but not on {1 1 1} ceria crystallographic planes. The RhPd reconstructing and tuned activation over ceria nanocubes and nanorods is considered the main reason for better catalytic activity with respect to conventional catalysts based on polycrystalline ceria.

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Section: Catalytic Performancesupporting

confidence: 67%

Section: Introductionmentioning

confidence: 99%

The influence of nano-architectured CeO supports in RhPd/CeO2 for the catalytic ethanol steam reforming reaction

Divins

Casanovas

et al. 2015

Catalysis Today

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“…These features could be exploited in the reforming of raw bioethanol samples. Divins et al [74] reported similar product distribution when reforming synthetic ethanol/water and raw bioethanol samples over a RhPd/CeO2 catalyst, due to a synergy between the active metals and the support. However, the changing Ce +3 /Ce +4 ratio during the stability test can slightly affect the catalyst selectivity during larger period of times.…”

Section: Tgamentioning

confidence: 82%

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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“…1 The principal advantage of the hydrogen production from alcohols over that from fossil resources is because the former can be obtained from renewable supplies making it an environmental friendly process. [8][9][10] Notice that light alcohols are also used as feedstock for obtaining other chemicals such as aldehydes or ketones.…”

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confidence: 99%

Methanol dissociation on bimetallic surfaces: validity of the general Brønsted–Evans–Polanyi relationship for O–H bond cleavage

2016

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Density functional theory (DFT) calculations were employed to study the dissociation of the O-H bond in methanol on several planar and stepped bimetallic transition metal surfaces, composed of elements showing high or moderate activity towards this reaction, namely, Ni, Rh, Ru, Ir, Pd, Au, Zn and Cu. The activation energies for the O-H bond cleavage were compared with those estimated using a Brønsted-Evans-Polanyi (BEP) relationship for the RO-H bond breakage on pure metal transition surfaces, relating the activation energy for the reaction with the adsorption energies of the reaction products, ROc and Hc adsorbed on the surface of the catalyst. Furthermore, the average differences between the values of the activation energies calculated with the exhaustive determination of the full reaction path and location of the transition state on each surface model and the activation energies obtained from the BEP relationship with the simple calculation of the adsorption energies of the ROc and Hc species are $0.14 eV. This suggests that the BEP relationship developed upon the consideration of data for dissociation of the O-H bond in alcohols and water on pure metal surfaces is also valid for a qualitative prediction of the methanol activation energy on bimetallic surfaces.

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Bio-ethanol steam reforming and autothermal reforming in 3-μm channels coated with RhPd/CeO2 for hydrogen generation

Cited by 61 publications

References 23 publications

The influence of nano-architectured CeO supports in RhPd/CeO2 for the catalytic ethanol steam reforming reaction

The influence of nano-architectured CeO supports in RhPd/CeO2 for the catalytic ethanol steam reforming reaction

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

Methanol dissociation on bimetallic surfaces: validity of the general Brønsted–Evans–Polanyi relationship for O–H bond cleavage

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