Experimental and theoretical study about sulfur deactivation of Ni/ CeO2 and Rh/CeO2 catalysts

Ocsachoque, Marco Antonio; Russman, Juan I. Eugenio; Irigoyen, Beatriz; Gazzoli, Delia; González, María Teresa Rodríguez

doi:10.1016/j.matchemphys.2015.12.062

Cited by 34 publications

(11 citation statements)

References 35 publications

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“…Finally, at temperatures higher than 800°C, the TCD signal is attributed to the reduction of bulk CeO 2 species. Comparison of the reduction profiles of Rh-Ni/CeO 2 and Ni/CeO 2 indicates that the presence of Rh promotes CeO 2 reduction, since the reduction profile of the Rh-Ni sample is shifted to lower temperatures, which can be attributed to hydrogen spillover during RhO x reduction (Ocsachoque et al, 2016 ).…”

Section: Resultsmentioning

confidence: 99%

Partial Oxidation of Methane to Syngas Over Nickel-Based Catalysts: Influence of Support Type, Addition of Rhodium, and Preparation Method

et al. 2019

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There is great economic incentive in developing efficient catalysts to produce hydrogen or syngas by catalytic partial oxidation of methane (CPOM) since this is a much less energy-intensive reaction than the highly endothermic methane steam reforming reaction, which is the prominent reaction in industry. Herein, we report the catalytic behavior of nickel-based catalysts supported on different oxide substrates (Al2O3, CeO2, La2O3, MgO, and ZrO2) synthesized via wet impregnation and solid-state reaction. Furthermore, the impact of Rh doping was investigated. The catalysts have been characterized by X-ray diffraction, N2 adsorptiondesorption at −196°C, temperature-programmed reduction, X-ray photoelectron spectroscopy, O2-pulse chemisorption, transmission electron microscopy, and Raman spectroscopy. Supported Ni catalysts were found to be active for CPOM but can suffer from fast deactivation caused by the formation of carbon deposits as well as via the sintering of Ni nanoparticles (NPs). It has been found that the presence of Rh favors nickel reduction, which leads to an increase in the methane conversion and yield. For both synthesis methods, the catalysts supported on alumina and ceria show the best performance. This could be explained by the higher surface area of the Ni NPs on the alumina surface and presence of oxygen vacancies in the CeO2 lattice, which favor the proportion of oxygen adsorbed on defect sites. The catalysts supported on MgO suffer quick deactivation due to formation of a NiO/MgO solid solution, which is not reducible under the reaction conditions. The low level of carbon formation over the catalysts supported on La2O3 is ascribed to the very high dispersion of the nickel NPs and to the formation of lanthanum oxycarbonate, through which carbon deposits are gasified. The catalytic behavior for catalysts with ZrO2 as support depends on the synthesis method; however, in both cases, the catalysts undergo deactivation by carbon deposits.

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Section: Resultsmentioning

confidence: 99%

Partial Oxidation of Methane to Syngas Over Nickel-Based Catalysts: Influence of Support Type, Addition of Rhodium, and Preparation Method

et al. 2019

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“…The peak observed at 109 °C is associated with The monometallic catalyst without Pt showed a much more complex reduction profile with various peaks in the range 200-500 • C. As previously reported, the low-temperature zone (which comprises the peaks located at 237 and 289 • C) is ascribed to the adsorbed oxygen reduction [48]. However, the contribution of bulk NiO particles reduction dispersed on ceria support cannot be excluded [49]. The peak observed in the middle-temperature zone at 334 • C can be correlated to the reduction of NiO interacting with (but not chemically bound to) the support; finally, the peak observed at 435 • C can be associated to the formation of Ni-Ce solid solution and/or to the reduction of CeO 2 surface oxygen, shifted towards lower temperature due to H 2 spillover promoted by Ni [26,50].…”

Section: Catalysts Characterizationmentioning

confidence: 53%

Renewable Hydrogen from Ethanol Reforming over CeO2-SiO2 Based Catalysts

et al. 2017

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Abstract:In this research, a bimetallic Pt-Ni/CeO 2 -SiO 2 catalyst, synthetized via wet impregnation, was successfully employed for the oxidative steam reforming of ethanol between 300 and 600 • C. The reaction performance of the Pt-Ni catalyst was investigated and compared with the Ni/CeO 2 -SiO 2 , Pt/CeO 2 -SiO 2 as well as CeO 2 -SiO 2 sample. The bimetallic catalyst displayed the best results in terms of hydrogen yield and by-products selectivity, thus highlighting the crucial role of active species (Pt and Ni) in promoting ethanol conversion and reaching the products distribution predicted by thermodynamics. The most promising sample, tested at 500 • C for more than 120 h, assured total conversion and no apparent deactivation, demonstrating the stability of the selected formulation. By changing contact time, the dependence of carbon formation rate on space velocity was also investigated.

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“…Furthermore, those catalysts could also be exploited to convert raw biogas (which mainly contains CH 4 and CO 2 ) into syngas . However, more attention is needed to develop sulfur‐resistant catalysts, because H 2 S is the main impurity in biogas …”

Section: Introductionmentioning

confidence: 99%

“…27,28 However, more attention is needed to develop sulfur-resistant catalysts, because H 2 S is the main impurity in biogas. 29,30 Oxidative coupling of methane by CO 2 (CO 2 -OCM) is a direct process to convert both CH 4 and CO 2 to higher value hydrocarbons, particularly ethane and ethylene (Equations 9 and 10):…”

Section: Introductionmentioning

confidence: 99%

Advances in catalytic conversion of methane and carbon dioxide to highly valuable products

Cai

2019

Energy Science & Engineering

124

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Two typical processes have been developed for the conversion of methane and carbon dioxide to higher valuable products: dry reforming of methane (DRM) and CO2‐oxidative coupling of methane (CO2‐OCM). Numerous articles reviewed progresses in either DRM or CO2‐OCM, but no one covers both processes. In this review article, we systematically evaluated progresses in both DRM and CO2‐OCM processes for conversion of methane and CO2 to highly valuable products. Critical issues, which are carbon deposition and high energy cost for DRM and the contradiction between large activity and high selectivity for CO2‐OCM, were emphasized. Strategies to develop effective catalysts were evaluated, including the enhancement of metal‐support interactions, the introduction of promotors, the formation of solid solutions, and the construction of core‐shell structures. Plasma and photocatalysis were discussed as new promising technologies for DRM and CO2‐OCM.

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Experimental and theoretical study about sulfur deactivation of Ni/ CeO2 and Rh/CeO2 catalysts

Cited by 34 publications

References 35 publications

Partial Oxidation of Methane to Syngas Over Nickel-Based Catalysts: Influence of Support Type, Addition of Rhodium, and Preparation Method

Partial Oxidation of Methane to Syngas Over Nickel-Based Catalysts: Influence of Support Type, Addition of Rhodium, and Preparation Method

Renewable Hydrogen from Ethanol Reforming over CeO2-SiO2 Based Catalysts

Advances in catalytic conversion of methane and carbon dioxide to highly valuable products

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