Water-gas shift: comparative screening of metal promoters for metal/ceria systems and role of the metal

Jacobs, Gary; Chenu, Emilie; Patterson, Patricia M.; Williams, Leann; Sparks, Dennis E.; Thomas, Gerald A.; Davis, Burtron H.

doi:10.1016/j.apcata.2003.09.007

Cited by 223 publications

(61 citation statements)

References 12 publications

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“…Two peaks related with CeO 2 reduction were found for the Ce doped samples. As shown in previous works dealing with ceria supports (Andreeva et al 2002;Fu et al 2003Fu et al , 2005Jacobs et al 2004;Lai et al 2006;Carabineiro et al 2010b, f, h, g), the two major peaks seen in the TPR profiles correspond to the reduction of bulk oxygen and the formation of cerium oxides of lower oxidation state (high temperature peak at *750°C) and to the reduction of surface oxygen species (lower temperature peak at *450°C), respectively. These peaks were observed around 720 and 440°C, in our case (Table 2).…”

Section: Temperature Programmed Reductionmentioning

confidence: 99%

Gold on oxide-doped alumina supports as catalysts for CO oxidation

2011

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The effect of doping a commercial alumina support with metal oxides of Ce, Co, Cu, Fe, La, Mg, Mn, Ni and Zn was investigated. Doped d-Al 2 O 3 samples were obtained by simple physical mixture (PM) of the alumina with the desired commercial oxide and by traditional impregnation of alumina with precursor salts of the same metals followed by calcination (IC). The metal load (7% wt.) was the same in both cases. Gold (1% wt.) was loaded using a liquid phase reductive deposition method. The obtained materials were characterized by adsorption of N 2 at -196°C, temperature programmed reduction, X-ray diffraction, energy-dispersive X-ray spectrometry and transmission electron microscopy. Both samples prepared by PM and IC showed a mixture of the d-alumina phase with the respective metal oxide, but the BET surface areas of the IC samples were, in general, higher than those of the PM materials. The particle size of the oxide phases were larger for the PM samples than for the IC materials. Nevertheless, catalytic experiments for CO oxidation showed that PM samples were much more active than IC. That could be explained by the size of gold nanoparticles, well known to be related with catalytic activity, that was lower in samples prepared by PM (7-16 nm) than by IC (11-17 nm). Gold was found to be in the metallic state. The most active samples were aluminas containing Zn and Fe prepared by PM that had the smallest gold nanoparticles sizes (7-13 and 8-12 nm, respectively) and had room temperature activities for CO conversion of 0.62 and 1.34 mol CO h -1 g Au -1 , respectively, which are larger than those found in the literature for doped c-alumina samples.

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Section: Temperature Programmed Reductionmentioning

confidence: 99%

Gold on oxide-doped alumina supports as catalysts for CO oxidation

2011

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“…Moreover, the high thermal stability of ceria is attractive for reactions which are conducted at high temperatures [2]. Therefore, ceria has been extensively utilized in three-way catalysts [5][6][7] and fuel cells [8,9], as well as investigated for its activity in catalytic reactions such as CO oxidation [10,11], steam reforming [12][13][14][15][16][17], and water gas shift (WGS) [18,19].…”

Section: +mentioning

confidence: 99%

Effect of Microgravity on Synthesis of Nano Ceria

et al. 2015

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Cerium oxide (CeO2) was prepared using a controlled-precipitation method under microgravity at the International Space Station (ISS). For comparison, ceria was also synthesized under normal-gravity conditions (referred as control). The Brunauer-Emmett-Teller (BET) surface area, pore volume and pore size analysis results indicated that the ceria particles grown in space had lower surface area and pore volume compared to the control samples. Furthermore, the space samples had a broader pore size distribution ranging from 30-600 Å, whereas the control samples consisted of pore sizes from 30-50 Å range. Structural information of the ceria particles were obtained using TEM and XRD. Based on the TEM images, it was confirmed that the space samples were predominantly nano-rods, on the other hand, only nano-polyhedra particles were seen in the control ceria samples. The average particle size was larger for ceria samples synthesized in space. XRD results showed higher crystallinity as well as larger mean crystal size for the space samples. The effect of sodium hydroxide concentration on synthesis of ceria was also examined using 1 M and 3 M solutions. It was found that the control samples, prepared in 1 M and 3 M sodium hydroxide solutions, did not show a significant difference between the two. However, when the ceria samples were prepared OPEN ACCESSCatalysts 2015, 5 1307 in a more basic medium (3 M) under microgravity, a decrease in the particle size of the nano-rods and appearances of nano-polyhedra and spheres were observed.

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“…Previous studies have addressed the behavior of NiO/CeO2 or Ni/CeO2 systems as catalysts for the title reaction. Despite good activities were reported, Ni containing catalysts suffer for deactivation mainly due to the well-known metallic particles sintering process together with the accumulation of carbon deposits on the catalysts surface [10,11].…”

Section: Introductionmentioning

confidence: 99%

Ni-CeO2/C Catalysts with Enhanced OSC for the WGS Reaction

et al. 2015

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Abstract:In this work, the WGS performance of a conventional Ni/CeO2 bulk catalyst is compared to that of a carbon-supported Ni-CeO2 catalyst. The carbon-supported sample resulted to be much more active than the bulk one. The higher activity of the Ni-CeO2/C catalyst is associated to its oxygen storage capacity, a parameter that strongly influences the WGS behavior. The stability of the carbon-supported catalyst under realistic operation conditions is also a subject of this paper. In summary, our study represents an approach towards a new generation of Ni-ceria based catalyst for the pure hydrogen production via WGS. The dispersion of ceria nanoparticles on an activated carbon support drives to improved catalytic skills with a considerable reduction of the amount of ceria in the catalyst formulation.

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Water-gas shift: comparative screening of metal promoters for metal/ceria systems and role of the metal

Cited by 223 publications

References 12 publications

Gold on oxide-doped alumina supports as catalysts for CO oxidation

Gold on oxide-doped alumina supports as catalysts for CO oxidation

Effect of Microgravity on Synthesis of Nano Ceria

Ni-CeO2/C Catalysts with Enhanced OSC for the WGS Reaction

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