Selective oxidation of CO in the presence of hydrogen on CuO/CeO2 catalysts modified with Fe and Ni oxides

Firsova, A. A.; Il’ichev, A. N.; Khomenko, T. I.; Gorobinskii, L. V.; Maksimov, Yu. V.; Suzdalev, I. P.; Корчак, В. Н.

doi:10.1134/s0023158407020139

Cited by 32 publications

(7 citation statements)

References 17 publications

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“…Iron, nickel or tin can increase the activity and selectivity of copper-ceria catalysts, although the CO oxidation occurs over copper species. 42,56,68 Doping copper-ceria with Pt can increase the activity, but no beneficial effect on the selectivity was observed when doping with Pt, Ru, Pd, Ni or Co. 69,70 Chen et al found increased activity upon adding zirconia, but only at low concentration (10 mol%). 63 Although the above reports show that copper-ceria-based catalysts can give high CO PROX activities and selectivities, important parameters for practical application are long term stability (in feeds containing H 2 O and CO 2 ), fast CO conversion and, of course, a low CO effluent concentration.…”

Section: Preferential Co Oxidation (Prox)mentioning

confidence: 99%

Sustainable selective oxidations using ceria-based materials

2010

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This Perspective covers sustainable oxidation processes using doped cerias, ceria-supported catalysts and ceria-based mixed oxides. Firstly, we consider the general properties of ceria-based catalysts. We outline the advantages of the ceria redox cycle, and explain the dynamic behaviour of these catalysts in the presence of metal additives and dopants. We then review three types of catalytic oxidation processes: preferential CO oxidation (PROX), oxidative dehydrogenation and the selective oxidations of hydrocarbons and inorganics. The preferential oxidation of CO from hydrogen-rich mixtures is interesting for fuel cell applications. Copper-ceria catalysts, where the copper species are well dispersed and interact strongly with the ceria surface, show good selectivity and activity. The oxidative dehydrogenation of small alkanes is another important potential application. To avoid mixing oxygen and hydrocarbons at high temperatures, one can run the dehydrogenation over a conventional Pt/Sn catalyst while burning the hydrogen formed using the ceria lattice oxygen. This safer redox process allows separate tuning of the dehydrogenation and hydrogen combustion stages. A combinatorial screening showed good results for ceria doped with Pb, Cr or Bi, amongst others. Finally, we also discuss the catalytic selective oxidation of various hydrocarbons, oxygenates and inorganic molecules (H 2 S, H 2 and NH 3). The goal here is either product valorisation or waste stream purification. Ceria-based materials show promise in a variety of such selective oxidations.

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Section: Preferential Co Oxidation (Prox)mentioning

confidence: 99%

Sustainable selective oxidations using ceria-based materials

2010

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“…Although a large number of studies have focused on the catalytic properties over Cu/Ce catalysts, the in-depth insight into the catalytic behavior for the modification of Cu/Ce catalysts by iron (Fe) species in the reaction process of CO-PROX (especially the tolerance of H 2 O and CO 2 as well as the stability) is relatively less. At present, for the selective CO oxidation, some authors found that the incorporation of Fe species into Cu/Ce catalysts prepared by wet impregnation and single-step citrate method generated better reducibility to improve the interaction between Cu and Ce, which leads to the higher dispersion of copper, thus having a positive effect on the CO oxidation activity. , Other researchers deemed that the introduction of Fe additives into Cu/Ce catalysts in the certain preparation procedure promoted the generation of additional amount of active sites related to CuO because of the electron–ion interactions, which improved the CO-PROX activity . However, the negative CO oxidation activity was reported for using CuO-CeO 2 catalysts doped with Fe species when the coprecipitated method was applied .…”

Section: Introductionmentioning

confidence: 99%

Unravelling the Nature of the Active Species as well as the Doping Effect over Cu/Ce-Based Catalyst for Carbon Monoxide Preferential Oxidation

et al. 2019

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The active sites of a mixed Cu/Ce material and the doping effect of typical element (iron, Fe) on the active species and the catalytic behavior of Cu/Ce for CO preferential oxidation in rich H2 (CO-PROX) were investigated by in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), in situ oxygen storage capacity measurement (OSC) combined with designed temperature-programmed reduction (TPR), along with Raman, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and temperature-programmed desorption/reduction of CO (CO-TPD/TPR). These results showed that two kinds of surface active center were involved in the CuCe- and Fe-doped CuCe systems, that is, Cu+ as adsorption sites for the chemisorption and the activation of CO molecules, the surface reactive oxygen (the highly dispersed oxygen and surface lattice oxygen) that directly participated in the whole CO oxidation process. The addition of Fe into CuCe sample resulted in the incorporation of Fe into CeO2 lattice forming Fe–O–Ce structure and generated more oxygen vacancies, which not only enhanced the interaction between Cu and Ce to form more Cu+ absorption sites but also trapped the gas-phase oxygen and promoted the release of subsurface lattice oxygen to supply more reactive oxygen. Thus, the turnover frequency (TOF) value was increased from 3.62 × 10–2 s–1 for CuCe to 4.50 × 10–2 s–1 for Fe-doped CuCe. Moreover, with the enhancement of the lattice oxygen migration combined with the promotional role of Fe on the water gas shift (WGS), the capacity of the resistance to CO2 and H2O was enhanced for Fe-doping CuCe, and the corresponding stability time was largely prolonged from 170 to 400 h, in the coexistence of CO2 and H2O.

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“…CuO/CeO 2 catalysts represent a cheaper and more selective alternative to noble metals and have been widely investigated in the last decades [3,5,[32][33][34], focusing on methods to further improve performance based on doping [6,8,10,18,22,[35][36][37][38][39][40][41][42] or unconventional preparation methods [4,11,12,18,[43][44][45][46][47].…”

Section: Introductionmentioning

confidence: 99%

Improved CO-PROX Performance of CuO/CeO2 Catalysts by Using Nanometric Ceria as Support

2018

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Abstract:Despite of the huge number of papers about the catalytic preferential oxidation of CO (CO-PROX) for the purification of H 2 streams, there is still a need for more effective catalysts in order to reduce the large required catalyst volume of CO-PROX unity. In this work, large surface area nanometric ceria was used as support for CuO/CeO 2 catalysts with CuO load up to 10 wt % easily dispersed by wet impregnation. Catalysts were characterized by ICP-MS, XRD, SEM/EDS, N 2 physisorption, H 2 temperature programmed reduction (TPR), and CO 2 temperature programmed desorption (TPD) and tested under different reaction conditions (including under feed containing inhibiting species such as CO 2 and H 2 O). Catalytic tests revealed that our samples show high activity and selectivity even under stringent reaction conditions; moreover, they result among the most active catalysts when compared to those reported in the scientific literature. The high activity can be related to the enhanced amount of highly dispersed copper sites in strong interaction with ceria related to the nature of the nanometric support, as evidenced by the characterization techniques. Despite the high concentration of active copper sites, catalytic performance is limited by CO 2 desorption from ceria in the neighborhood of copper sites, which prevents a further improvement. This suggests that new catalyst formulations should also provide a lower affinity towards CO 2 .

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Selective oxidation of CO in the presence of hydrogen on CuO/CeO2 catalysts modified with Fe and Ni oxides

Cited by 32 publications

References 17 publications

Sustainable selective oxidations using ceria-based materials

Sustainable selective oxidations using ceria-based materials

Unravelling the Nature of the Active Species as well as the Doping Effect over Cu/Ce-Based Catalyst for Carbon Monoxide Preferential Oxidation

Improved CO-PROX Performance of CuO/CeO2 Catalysts by Using Nanometric Ceria as Support

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