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Shudong Wang - One of the best experts on this subject based on the ideXlab platform.
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Autothermal Reforming of methane over rh ce0 5zr0 5o2 catalyst effects of the crystal structure of the supports
Fuel Processing Technology, 2010Co-Authors: Zhongsha Yua, Lei Cao, Shudong WangAbstract:Abstract Autothermal Reforming of methane (ATR) was studied over Rh catalysts supported on Ce 0.5 Zr 0.5 O 2 solid solution, which were synthesized by four different routes, including reverse micro-emulsion (ME), co-precipitation (CP), urea-combustion (UC) and sol–gel (SG) method. The textural and structural properties of the as-prepared solid solutions were carefully examined by means of BET, TEM, XRD and Raman techniques. Results showed that the ME sample exhibited a single cubic phase, whereas tetragonal or mixed phases such as cubic CeO 2 -rich and tetragonal ZrO 2 -rich phases, were found in the case of CP, UC and SG. Vegard's rule revealed that the homogeneity of these as-prepared solid solutions followed the order of ME > CP > UC > SG. TPR and CO-pulse experiments were adopted to evaluate the reducibility and the oxygen storage capacity (OSC) of the catalysts. It was found that the more homogenous the solid solution is, the more reducibility it is, i.e. both the reducibility and OSC followed the same order as that of homogeneity. Rh/ME showed the highest activity and H 2 /CO ratio and such performance was maintained without significant loss during 10 h experiment. On the contrary, the other three catalysts having mixed phases showed remarkably deactivation in terms of H 2 /CO due to the loss of BET area. To elucidate the resistance toward carbon formation of these catalysts, methane decomposition experiments and following temperature-programmed-oxidation (TPO) were studied. As expected, the resistance toward carbon formation could be enhanced by the improved OSC of the catalyst.
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correlation between catalytic selectivity and oxygen storage capacity in Autothermal Reforming of methane over rh ce0 45zr0 45re0 1 catalysts re la pr nd sm eu gd tb
Catalysis Communications, 2009Co-Authors: Zhongsha Yua, Lei Cao, Shudong WangAbstract:Trivalent rare-earth (RE = La, Pr, Nd, Sm, Eu, Gd, Tb)-doped Ce0.45Zr0.45RE0.1 solid solutions were synthesized via reverse micro-emulsion method and the catalytic performance of the Rh-supported catalysts was investigated in Autothermal Reforming of methane (ATR). It was found that CH4 conversion went through a maximum as a function of oxygen storage capacity (OSC) value of the support. Higher OSC will help to enhance the reactivity toward water-gas-shift (WGS) reaction, resulting higher H-2/CO ratio. A striking correlation between OSC and H-2/CO ratio was observed, which presented a maximum for the Rh/CZLa (3.4) and a minimum for the Rh/CZTb (2.6) catalysts. (C) 2009 Elsevier B. V. All rights reserved.
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Autothermal Reforming of methanol in a mini reactor for a miniature fuel cell
International Journal of Hydrogen Energy, 2007Co-Authors: Chunxi Zhang, Na Liu, Shudong WangAbstract:Abstract A novel mini-reactor for hydrogen production has been successfully fabricated, which integrates one Reforming chamber, one catalytic combustion chamber and two preheating chambers. It can be started up at room temperature by the combustion of liquid methanol in the combustion chamber within 10 min , and it also can keep self-sustained, i.e. without any external heating during the operating process. This reactor has been tested for carrying out the reaction of Autothermal Reforming of methanol for hydrogen production. The reactor performance has been investigated using three crucial parameters, namely, the molar ratios of water/methanol, oxygen/methanol and the flow distribution, respectively. The experimental runs have demonstrated the optimal methanol conversion of 96.4%, containing 51.04% H 2 , 26.68% N 2 , 2.12% CO and 20.16% CO 2 in the reformed gas. Furthermore, the reformer which can supply reformed gas at the maximum flow rate of 125 l (STP)/h has been integrated with a miniature fuel cell, the small power system can produce continuous power at the energy density of 92 mW / cm 2 for 4 h.
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Autothermal Reforming of gasoline on rh based monolithic catalysts
International Journal of Hydrogen Energy, 2007Co-Authors: Shudong WangAbstract:Abstract With an objective to conserve noble metal usage and improve the Reforming performance, one engineered catalyst, a Rh-based monolithic catalyst with an optimized composition of 0.3 wt%Rh/3 wt%MgO/20 wt%CeO2–ZrO2 supported on cordierite monolith was developed for Autothermal Reforming (ATR) of commercial gasoline and its surrogates. At a temperature range of 650– 800 ∘ C , O2/C molar ratio of 0.38–0.45 (air as oxygen source) and H2O/C ratio of 2.0, alkanes (e.g., octane) were fully converted into reformate with minor amount of CH4 remaining whereas aromatics (e.g., toluene) converted into CH4-free reformate at a relatively higher temperature. Compared with pellet catalysts, monolithic catalysts with equivalent amount of net catalytic components demonstrated higher activity and selectivity due to the intensified Reforming process. This catalyst also showed quite good resilience to sulfur poisoning, although the presence of sulfur in source fuels could make the hydrogen productivity suffer. Moreover, one 1 kW gasoline fuel processor built on a scaled-up catalyst was successfully operated at a ( H 2 + CO ) throughput of 0.9–1.0 m3/h for 60 h. The catalyst sintering and carbon formation which were exacerbated by sulfur-poisoning mainly accounted for the slowly deactivation of the catalyst. The sintering was also aggravated by the low thermal conductivity of the cordierite substrates and by the inharmonic reaction rates of catalytic partial oxidation and steam Reforming. Additionally, some issues related to gasoline fuel processor and its monolithic catalysts were also addressed.
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Autothermal Reforming of n octane on ru based catalysts
Applied Catalysis A-general, 2005Co-Authors: Shudong WangAbstract:Abstract In an attempt to effectively integrate catalytic partial oxidation (CPO) and steam Reforming (SR) reactions on the same catalyst, Autothermal Reforming (ATR) of n -octane was addressed based on thermodynamic analysis and carried out on a non-pyrophoric catalyst 0.3 wt.% Ru/K 2 O-CeO 2 /γ-Al 2 O 3 . The ATR of n -octane was more efficient at the molar ratio of O 2 /C 0.35–0.45 and H 2 O/C 1.6–2.2 (independent parameters), respectively, and Reforming temperature of 750–800 °C (dependent parameter). Among the sophisticated reaction network, the main reaction thread was deducted as: long-chain hydrocarbon → CH 4 , short-chain hydrocarbon → CO 2 , CO and H 2 formation by steam Reforming, although the parallel CPO, decomposition and reverse water gas shift reaction took place on the same catalyst. Low temperature and high steam partial pressure had more positive effect on CH 4 SR to produce CO 2 other than CO. This was verified by the tendency of the outlet reformate to the equilibrium at different operation conditions. Furthermore, the loss of active components and the formation of stable but less active components in the catalyst in the harsh ATR atmosphere firstly make the CO inhibition capability suffer, then eventually aggravated the ATR performance, which was verified by the characterizations of X-ray fluorescence, BET specific surface areas and temperature programmed reduction.
Lars J Pettersso - One of the best experts on this subject based on the ideXlab platform.
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evaluation of co la and mn promoted rh catalysts for Autothermal Reforming of commercial diesel aging and characterization
Applied Catalysis B-environmental, 2015Co-Authors: Moa Z Granlund, Marita Nilsso, Kjell Jansso, Lars J Pettersso, Jazae DawodyAbstract:In this study, three bimetallic catalysts are evaluated for Autothermal Reforming (AIR) of fuels (1 wt.% Rh and 6 wt.% X (X= Co, La or Mn) supported on high-surface area CeO2-ZrO2). The catalysts a ...
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zone coated rh based monolithic catalyst for Autothermal Reforming of diesel
Applied Catalysis B-environmental, 2011Co-Authors: Xanthias Karatzas, Jazae Dawody, A W Gra, Erik Elm Svensso, Lars J PetterssoAbstract:Abstract In this work we present results of hydrogen generation from diesel via Autothermal Reforming (ATR) obtained with monolithic catalysts consisting of either one or two layers of monometallic Rh and bimetallic RhPt washcoats. The Rh metal loading of the monometallic washcoats was varied between 0.5, 1.0 and 3.0 wt%, while the weight ratio of Rh:Pt in the bimetallic washcoats was kept constant at 1:1. Furthermore, non-doped and CeLa-doped catalysts were also tested to detect differences in catalyst activity. The catalysts consisting of two layers of washcoats were termed zoned catalysts and each layer was applied to some given length in the axial direction of the monolith. All catalysts were prepared by impregnation using the incipient wetness technique with δ-Al2O3 as support and deposited onto 400 cpsi cordierite monoliths. A total of eight catalysts, including both single layered and zone-coated, were tested in a bench-scale reactor using low-sulfur diesel as fuel at operating conditions H2O/C = 2.5, O2/C = 0.49 (λ = 0.33), GHSV = 17,000 h−1 and P = 1 atm. The results showed that the zoned catalyst, covered with the two washcoats Rh1.0Pt1.0–Ce10La5.0/δ-Al2O3 and Rh3.0–Ce10La10/δ-Al2O3, respectively, was most active in terms of fuel conversion and hydrogen production. The zoned catalyst's long-term performance and stability was also evaluated in a full-scale reactor using low-sulfur and Fischer–Tropsch diesels at operating conditions H2O/C = 2.5, O2/C = 0.49 (λ = 0.33), GHSV = 10,800 h−1, P = 1 atm, and at H2O/C = 2.4, O2/C = 0.39 (λ = 0.26), GHSV = 10,200 h−1, P = 1 atm, respectively. The results showed that high fuel conversion and hydrogen production were obtained from both fuels. In addition, partial oxidation and steam Reforming reactions were identified by closely studying the distribution of the analyzed product gas composition and the temperature measurements. Fresh and aged samples of the catalysts were characterized by N2-BET, H2 chemisorption, XRD, H2-TPR, O2-TPO and XPS analyses.
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catalytic properties of pd supported on zno znal2o4 al2o3 mixtures in dimethyl ether Autothermal Reforming
Applied Catalysis B-environmental, 2009Co-Authors: Marita Nilsso, Kjell Jansso, Pete Jozsa, Lars J PetterssoAbstract:The catalytic properties of Pd supported on mixtures of zinc oxide, zinc aluminate, and alumina, prepared from gamma-alumina and zinc nitrate, were studied for Autothermal Reforming (ATR) of dime ...
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evaluation of pd based catalysts and the influence of operating conditions for Autothermal Reforming of dimethyl ether
Applied Catalysis B-environmental, 2007Co-Authors: Marita Nilsso, Pete Jozsa, Lars J PetterssoAbstract:Abstract A series of different Pd-based catalysts supported on ceramic monoliths were synthesized and tested in a screening study for Autothermal Reforming of dimethyl ether (DME). Alumina-supported Pd was shown to be very active for this reaction at temperatures between 350 and 400 °C. Adding Zn to Pd/γ-Al 2 O 3 decreased the activity of decomposition reactions leading to better Reforming activity, and resulting in high selectivity to carbon dioxide. Pd-Zn/γ-Al 2 O 3 was further evaluated in a parameter study varying oxygen-to-DME ratio, steam-to-DME ratio and temperature. The effect on the reformer performance of changing the operating conditions is discussed. The Pd-Zn/γ-Al 2 O 3 catalyst generated carbon monoxide concentrations below 5%, and hydrogen concentrations close to 50%. The catalyst performance was significantly improved by preconditioning in hydrogen. Results from a first round of catalyst characterization studies suggest that Pd–Zn species are formed on the alumina support following reduction.
Theodore Krause - One of the best experts on this subject based on the ideXlab platform.
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bimetallic ni rh catalysts with low amounts of rh for the steam and Autothermal Reforming of n butane for fuel cell applications
Applied Catalysis A-general, 2010Co-Authors: Magali Ferrando, Jeremy A Kropf, Theodore KrauseAbstract:Mono-metallic nickel and rhodium catalysts and bimetallic Ni-Rh catalysts supported on La-Al{sub 2}O{sub 3}, CeZrO{sub 2} and CeMgOx were prepared and evaluated for catalyzing the steam and Autothermal Reforming of n-butane. The binary Ni-Rh supported on La-Al{sub 2}O{sub 3} catalysts with low weight loading of rhodium exhibited higher H{sub 2} yields than Ni or Rh alone. The Ni-Rh/CeZrO{sub 2} catalyst exhibited higher performance and no coke formation, compared to the same metals on other supports. A NiAl{sub 2}O{sub 4} spinel phase was obtained on all Ni and Ni-Rh catalysts supported on La-Al{sub 2}O{sub 3}. The presence of rhodium stabilized the spinel phase as well as NiOx species upon Reforming while Ni alone was mostly reduced into metallic species. Extended X-ray absorption fine-structure analysis showed evidence of Ni-Rh alloy during preparation and even further after an accelerated aging at 900C in a H{sub 2}/H{sub 2}O atmosphere.
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rare earth first row transition metal perovskites as catalysts for the Autothermal Reforming of hydrocarbon fuels to generate hydrogen
Applied Catalysis A-general, 2008Co-Authors: Jennife R Mawdsley, Theodore KrauseAbstract:Abstract Perovskite oxides (ABO 3 ) containing rare earth elements on the A-site and first-row transition metal elements on the B-site were studied as catalysts for Autothermal Reforming of liquid hydrocarbon fuels to produce hydrogen for fuel cell systems. Experiments were conducted in a fixed bed microreactor at temperatures of 600–800 °C and gas-hourly space velocities (GHSV) ranging from 4600 to 28,000 h −1 using 2,2,4-trimethylpentane (isooctane) as a surrogate fuel. We have found that the two binary oxides, LaNiO 3 and LaCoO 3 , produced high yields of H 2 , but were not structurally stable. These perovskites decomposed to La 2 O 3 and Ni/NiO or Co/CoO under the reducing conditions present in the reformer. Three other binary oxides, LaCrO 3 , LaFeO 3 , and LaMnO 3 , were structurally stable but significantly less active than LaNiO 3 and LaCoO 3 . The partial substitution of chromium, iron, aluminum, gallium, or manganese on the B-site of LaNiO 3 to yield LaB x Ni 1− x O 3 was shown to improve the structural stability without a significant decrease in the H 2 yield. The effects of substituting rare earth elements for La and the substitution of alkaline earth elements on the A-site (La 1− y A y B x Ni 1− x O 3 ) on catalyst performance and stability were also investigated. Finally, La 0.8 Sr 0.2 M 0.9 Ni 0.1 O 3 catalysts (where M = Cr, Mn, or Fe) were tested with a “benchmark fuel” mixture containing from 0 to 50 ppmw sulfur. These tests showed that using chromium as a stabilizing element in LaNiO 3 imparts the most sulfur tolerance.
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role of the oxide support on the performance of rh catalysts for the Autothermal Reforming of gasoline and gasoline surrogates to hydrogen
Applied Catalysis A-general, 2006Co-Authors: Magali Ferrando, Theodore KrauseAbstract:Abstract Catalysts consisting of 2 wt% Rh deposited on Gd-CeO2, Y-ZrO2, γ-Al2O3, La-Al2O3, and CaAl12O19 were tested for the Autothermal Reforming (ATR) of isobutane and sulfur-free gasoline. The catalysts were characterized for activity by microreactor tests and temperature-programmed reduction (TPR), and for physical properties by surface area measurements, CO chemisorption, X-ray diffraction (XRD), and extended X-ray absorption fine structure (EXAFS) analyses. The order of activity for ATR of isobutane was Rh/La-Al2O3 > Rh/Y-ZrO2 > Rh/Gd-CeO2 > Rh/γ-Al2O3 > Rh/CaAl12O19, which paralleled the ranking of the catalysts based on the dispersion and reducibility of Rh, with Rh/La-Al2O3 having the highest dispersion and the lowest reduction temperature. After subjecting the catalysts to an accelerated ageing process, the activity for ATR of isobutane was similar for all catalysts except for Rh/Gd-CeO2, which experienced a significant loss in steam Reforming activity. Rhodium dispersion measurements confirmed that the ageing process had caused Rh to sinter on all of the supports. A major conclusion from this study is that the primary effect of the support was on the dispersion of Rh.
Lei Cao - One of the best experts on this subject based on the ideXlab platform.
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Autothermal Reforming of methane over rh ce0 5zr0 5o2 catalyst effects of the crystal structure of the supports
Fuel Processing Technology, 2010Co-Authors: Zhongsha Yua, Lei Cao, Shudong WangAbstract:Abstract Autothermal Reforming of methane (ATR) was studied over Rh catalysts supported on Ce 0.5 Zr 0.5 O 2 solid solution, which were synthesized by four different routes, including reverse micro-emulsion (ME), co-precipitation (CP), urea-combustion (UC) and sol–gel (SG) method. The textural and structural properties of the as-prepared solid solutions were carefully examined by means of BET, TEM, XRD and Raman techniques. Results showed that the ME sample exhibited a single cubic phase, whereas tetragonal or mixed phases such as cubic CeO 2 -rich and tetragonal ZrO 2 -rich phases, were found in the case of CP, UC and SG. Vegard's rule revealed that the homogeneity of these as-prepared solid solutions followed the order of ME > CP > UC > SG. TPR and CO-pulse experiments were adopted to evaluate the reducibility and the oxygen storage capacity (OSC) of the catalysts. It was found that the more homogenous the solid solution is, the more reducibility it is, i.e. both the reducibility and OSC followed the same order as that of homogeneity. Rh/ME showed the highest activity and H 2 /CO ratio and such performance was maintained without significant loss during 10 h experiment. On the contrary, the other three catalysts having mixed phases showed remarkably deactivation in terms of H 2 /CO due to the loss of BET area. To elucidate the resistance toward carbon formation of these catalysts, methane decomposition experiments and following temperature-programmed-oxidation (TPO) were studied. As expected, the resistance toward carbon formation could be enhanced by the improved OSC of the catalyst.
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correlation between catalytic selectivity and oxygen storage capacity in Autothermal Reforming of methane over rh ce0 45zr0 45re0 1 catalysts re la pr nd sm eu gd tb
Catalysis Communications, 2009Co-Authors: Zhongsha Yua, Lei Cao, Shudong WangAbstract:Trivalent rare-earth (RE = La, Pr, Nd, Sm, Eu, Gd, Tb)-doped Ce0.45Zr0.45RE0.1 solid solutions were synthesized via reverse micro-emulsion method and the catalytic performance of the Rh-supported catalysts was investigated in Autothermal Reforming of methane (ATR). It was found that CH4 conversion went through a maximum as a function of oxygen storage capacity (OSC) value of the support. Higher OSC will help to enhance the reactivity toward water-gas-shift (WGS) reaction, resulting higher H-2/CO ratio. A striking correlation between OSC and H-2/CO ratio was observed, which presented a maximum for the Rh/CZLa (3.4) and a minimum for the Rh/CZTb (2.6) catalysts. (C) 2009 Elsevier B. V. All rights reserved.
Fabio Passos - One of the best experts on this subject based on the ideXlab platform.
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investigation of ni ce zro2 catalysts in the Autothermal Reforming of methane
Fuel Processing Technology, 2011Co-Authors: Juliana S Lisboa, Luis E Terra, P R J Silva, H Saitovitch, Fabio PassosAbstract:Nickel catalysts supported on α-Al2O3, CeO2, ZrO2 and Ce–ZrO2 were investigated in the Autothermal Reforming of methane. Ce–ZrO2 supports formed a solid solution and presented better oxygen storage capacity per unit of mass of Ce when compared to CeO2. Diffuse reflectance UV–Vis spectroscopy spectra and temperature-programmed reduction profiles, showed the presence of Ni2+ in tetrahedral and octahedral geometries for catalysts supported on mixed oxides. Temperature-programmed surface reaction experiments showed that the catalytic activity for Autothermal Reforming is proportional to the amount of metallic sites on the surface. However, when operating under severe coking conditions, catalysts with a higher oxygen storage capacity were more stable in the Autothermal Reforming of methane. Time-differential angular correlation experiments provided an atomic view on how the mobility of oxygen on CeZrO2 is enhanced by the presence of Ni, which increases the stability of the catalyst.
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the effect of the addition of y2o3 to ni α al2o3 catalysts on the Autothermal Reforming of methane
Catalysis Today, 2010Co-Authors: Danielle Da Costa Rubim Messeder Dos Santos, Laureanny Madeira, Fabio PassosAbstract:Abstract The addition of Y2O3 to Ni/α-Al2O3 catalysts was investigated by BET surface area measurements, hydrogen chemisorption, X-ray diffraction, UV–vis diffuse reflectance spectroscopy, X-ray fluorescence, temperature programmed reduction, temperature programmed oxidation and cyclohexane dehydrogenation. Autothermal Reforming experiments were performed in order to evaluate the methane conversion and proceeded through an indirect mechanism consisting of total combustion of methane followed by CO2 and steam Reforming generating the synthesis gas. The Y2O3·Al2O3 supported catalysts presented better activity and stability in Autothermal Reforming reaction. Temperature programmed oxidation analysis demonstrated that the addition of Y2O3 resulted in a change of the type or the location of coke formed during reaction. None of the prepared catalyst presented deactivation by sintering under the tested conditions. The improved stability of supported catalysts Y2O3·Al2O3 was the result of minimizing the formation of coke on the surface of nickel particles.
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syngas production by Autothermal Reforming of methane on supported platinum catalysts
Applied Catalysis A-general, 2008Co-Authors: Jua A C Ruiz, Fabio Passos, Lisiane V Mattos, J M C Ueno, Eduardo F Souzaaguia, Fabio NoronhaAbstract:Abstract The performance of supported platinum catalysts on the Autothermal Reforming of methane was evaluated. The effect of the calcination temperature of the CeZrO 2 support and of the reaction conditions (reaction temperature, presence of CO 2 in the feedstock, and H 2 O/CH 4 molar ratio) was studied. The catalysts were characterized by BET, XRD, and OSC analyses and the reaction mechanism was determined by TPSR experiments. The TPSR analyses indicate that Autothermal Reforming of methane proceeds through a two-step mechanism (indirect mechanism) over all catalysts studied. The Pt/Ce 0.75 Zr 0.25 O 2 catalyst presented the best stability, which depends not only on the amount of oxygen vacancies of the support but also on the metal particle size. The higher reducibility and oxygen storage/release capacity of Pt/Ce 0.75 Zr 0.25 O 2 catalyst promote the mechanism of continuous removal of carbonaceous deposits from the active sites, which takes place at the metal-support interfacial perimeter. The water also participates in this mechanism, favouring the carbon removal of metal particle. Furthermore, the reaction conditions influenced significantly the behaviour of Pt/Ce 0.75 Zr 0.25 O 2 catalysts. The increase of H 2 O/CH 4 molar ratio had a beneficial effect on the methane conversion and on the H 2 /CO molar ratio. However, the increase of the reaction temperature had an opposite effect. Both the methane conversion and H 2 /CO molar ratio decreased with the increasing of reaction temperature. Moreover, the addition of CO 2 to feedstock increased the initial methane conversion, but decreased the stability of the catalyst.