Praseodymium (Pr) was impregnated to CeO2-ZrO2 solid solution by an impregnation method. The as-obtained Pr modi- fied CeO2-ZrO2 was impregnated with 1 wt.% Pd to prepare the catalysts. The structure and reducibilit...Praseodymium (Pr) was impregnated to CeO2-ZrO2 solid solution by an impregnation method. The as-obtained Pr modi- fied CeO2-ZrO2 was impregnated with 1 wt.% Pd to prepare the catalysts. The structure and reducibility of the fresh and hydrother- really aged catalysts were characterized by X-ray diffraction (XRD), Raman, X-ray photoelectron spectroscopy (XPS), CO chemi- sorption and H2 temperature-programmed reduction (H2-TPR). The oxygen storage capacity (OSC) was evaluated with CO serving as probe gas. Effects of impregnated Pr on the structure and oxygen storage capacity of catalysts were investigated. The results showed that the aged Pr-impregnated samples had much higher OSC and better reducibility than the unmodified ones. The scheme of structural evolutions of the catalysts with and without Pr was also established. Partial of the impregnated Pr diffused into the bulk of CeO2-ZrO2 during ageing, which inhibited the sintering, and increased the amount of oxygen vacancies in CeO2-ZrO2 support. Furthermore, those impregnated Pr species which covered on the surface of the support obstructed the strong metal-support interaction between Pd and Ce so as to reduce the encapsulation of Pd as well as the back spill-over of the oxygen during the catalytic process.展开更多
Ce-Zr-Al-Nd2O3 (CZAN) support materials were prepared by co-precipitation and impregnation methods, respectively. They were characterized by X-ray diffTaction (XRD), low temperature nitrogen adsorption-desorption,...Ce-Zr-Al-Nd2O3 (CZAN) support materials were prepared by co-precipitation and impregnation methods, respectively. They were characterized by X-ray diffTaction (XRD), low temperature nitrogen adsorption-desorption, oxygen pulsing technique, H2-temperamre programmed reduction (H2-TPR) and X-ray photoelectron spectroscopy (XPS). The Pd-only three-way catalysts (Pd-TWC) supported on these materials were prepared by incipient wetness method and studied by activity tests. The results demonstrated that the CZAN supports obtained by the two methods showed better structural, textural and redox properties than the CZA without Nd2O3, and the addition of Nd203 improved the catalytic activity of TWC. Especially, the CZAN-i support prepared by impregnation method had better thermal stability and redox property. Meanwhile, the Pd/CZAN-i catalyst exhibited the best catalytic performance. XPS measurements indicated that the Nd-modified samples possessed more Ce3+ and oxygen vacancies on the surface of samples, which led to a better redox property. The excellent redox property of support materials helped to improve the catalytic activity of TWC.展开更多
The Pd-only catalysts for motorcycle were prepared by impregnating CeO2-ZrO2-Al2O3 and CeO2-ZrO2+Al2O3 with PdCl2 aqueous solution and characterized by X-ray diffraction (XRD), oxygen storage capacity (OSC) and H2-tem...The Pd-only catalysts for motorcycle were prepared by impregnating CeO2-ZrO2-Al2O3 and CeO2-ZrO2+Al2O3 with PdCl2 aqueous solution and characterized by X-ray diffraction (XRD), oxygen storage capacity (OSC) and H2-temperature-programmed reduction (H2-TPR) methods. The XRD result indicated that the CeO2-ZrO2-Al2O3 compound prepared by co-precipitation formed a single solid solution and had good thermal stability, and Pd phase was not observed in all catalysts. The TPR results showed that the reduction temperature of Pd/CeO2-ZrO2-Al2O3 catalyst was lower than that of Pd/CeO2-ZrO2+Al2O3 catalyst whether they were fresh or aged catalysts. The Pd/CeO2-ZrO2-Al2O3 exhibited high three-way catalytic activity at low temperature, high thermal stability, and wide working window, suggesting a great potential for applications.展开更多
The catalytic behaviors of Pd(1.4 wt%)catalysts supported on CeO2-ZrO2-La2O3 mixed oxides with different Ce/Zr molar ratios were investigated for methanol decomposition.Nitrogen adsorption-desorption(BET),X-ray photoe...The catalytic behaviors of Pd(1.4 wt%)catalysts supported on CeO2-ZrO2-La2O3 mixed oxides with different Ce/Zr molar ratios were investigated for methanol decomposition.Nitrogen adsorption-desorption(BET),X-ray photoelectron spectroscopy(XPS),H2 temperature-programmed reduction(H2-TPR),X-ray diffraction(XRD)and Pd dispersion analysis were used for their characterization.Pd/Cc0.76Zro.18 La0.06O1.97 catalyst showed the highest BET surface area,best Pd dispersion capability and strongest metal-support interaction.Moreover,XPS showed that there was lattice defect oxygen or mobile oxygen.According to the result of O 1s measurements the lattice defect oxygen or mobile oxygen helped to maintain Pd in a partly oxidized state and increased the activity for methanol decomposition.The Pd/Ce0.76Zr0.18La0.0601.97 catalyst exhibited the best activity.A 100%conversion of methanol was achieved at around 260°C,which was about 20-40°C lower than other catalysts.展开更多
A series of CeO2-ZrO2-WO3 catalysts for the selective catalytic reduction (SCR) of NO with NH3 were prepared by hydrothermal method. The influence of calcination temperature on the catalytic activity, microstructure...A series of CeO2-ZrO2-WO3 catalysts for the selective catalytic reduction (SCR) of NO with NH3 were prepared by hydrothermal method. The influence of calcination temperature on the catalytic activity, microstructure, surface acidity and redox behavior of CeO2-ZrO2-WO3 catalyst was investigated using various characterization methods. It was found that the CeO2-ZrO2-WO3 catalyst calcined at 600 ℃ showed the best catalytic performance and excellent N2 selectivity, and yielded more than 90% NO conversion in a wide temperature range of 250-500 ℃ with a space velocity (GHSV) of 60000 131. As the calcination temperature was increased from 400 to 600 ℃, the NO conversion obviously increased, but decreased at higher calcination temperature. The results implied that the higher surface area, the strongest synergistic interaction, the superior redox property and the highly dispersed or amorphous WO3 species contributed to the excellent SCR activity of the CeO2-ZrO2-WO3 catalyst calcined at 600℃.展开更多
Nickel and sulfate co-modified CeO2-ZrO2 catalysts were prepared by sol-gel method. The catalysts were characterized by XRD, FTIR, XPS, NH3 chemisorption and NH3-SCR activity tests. The results showed that the enhance...Nickel and sulfate co-modified CeO2-ZrO2 catalysts were prepared by sol-gel method. The catalysts were characterized by XRD, FTIR, XPS, NH3 chemisorption and NH3-SCR activity tests. The results showed that the enhanced acidity of CeO2-ZrO2 catalysts by nickel and sulfate co-modification was responsible for the broadened temperature window and improved the selectivity to N2 in NH3-SCR deNOx. The introduction of nickel to CeO2-ZrO2 solid solutions resulted in more Ce3+ on surface of catalyst, leading to an in...展开更多
The electrocatalytic activity and stability of Pt/C catalyst modified by using CeO_2-ZrO_2 mixed oxides for the alcohols electrochemical oxidation as probes were investigated. The catalyst samples were characterized b...The electrocatalytic activity and stability of Pt/C catalyst modified by using CeO_2-ZrO_2 mixed oxides for the alcohols electrochemical oxidation as probes were investigated. The catalyst samples were characterized by X-ray diffraction(XRD) and scanning electron microscopy(SEM). The electrochemical properties were measured by a three electrode system on electrochemical workstation(IVIUM). The results showed that the presence of CeO_2-ZrO_2 might be associated with the presence of Pt, which indicated that possibly there was synergistic effect between CeO_2-ZrO_2 and Pt nanoparticles. The electrocatalytic activity and stability of Pt-MO_x/C(M=Ce, Zr) for methanol and ethanol oxidation was better than that of Pt-CeO_2/C, which was attributed to that CeO_2-ZrO_2 composited oxides enhanced oxygen mobility and promoted oxygen storage capacity(OSC). Furthermore, the best performance was found when the molar ratio of CeO_2 to ZrO_2 was 2:1 for the oxidation of methanol and ethanol. The forward peak current density of Pt-MO_x/C(M=Ce, Zr, Ce:Zr=2:1) towards the methanol electrooxidation was about 3.8 times that of Pt-CeO_2/C. Pt-MO_x/C(M=Ce, Zr) appeared to be a promising and less expensive methanol oxidation anode catalyst.展开更多
CeO2-based oxygen materials were prepared with co-precipitation method and characterized via Brunauer-Emmet Teller(BET)method,X-ray diffraction(XRD)and temperature-programmed reduction(H2-TPR).This paper revealed that...CeO2-based oxygen materials were prepared with co-precipitation method and characterized via Brunauer-Emmet Teller(BET)method,X-ray diffraction(XRD)and temperature-programmed reduction(H2-TPR).This paper revealed that three CeO2-based oxygen storage materials are all forming homogeneous solid solution.Among the samples,CeO2-ZrO2-Al2O3(CZA)has the best textural properties and excellent thermal stability.The specific surface area and pore volume of aged CZA are 90 m2/g and 0.29 mL/g.We proposed a viewpoint:Al3+ might insert among the interspace of fluorite structure or highly dispersal in solid solutions.展开更多
Potassium-modified ceria-zirconia catalyst was synthesized by wetness impregnation method.The ageing treatment was performed in static air at 800℃for 20 hr to evaluate the thermal stability of the catalyst.The cataly...Potassium-modified ceria-zirconia catalyst was synthesized by wetness impregnation method.The ageing treatment was performed in static air at 800℃for 20 hr to evaluate the thermal stability of the catalyst.The catalysts were characterized by X-ray diffraction,BET surface area,oxygen storage capacity,NOx-temperature programmed desorption and soot-temperature programmed oxidation measurements.By introduction of potassium,the maximum soot oxidation rate temperature(Tin)of the ceria-zirconia based catalyst decreased from 525 to 428℃in the presence of NO under a loose contact mode.The shift of Tm of the K-modified catalyst after ageing is only 15℃.The enhanced activity of the aged catalyst mainly lies in the promotional effect of potassium on the NOx/oxygen storage capacity as well as the soot-catalyst contact.展开更多
N2O is a major by-product emitted during low-temperature selective catalytic reduction of NO with NH3(NH3-SCR), which causes a series of serious environmental problems. A full understanding of the N2O formation mechan...N2O is a major by-product emitted during low-temperature selective catalytic reduction of NO with NH3(NH3-SCR), which causes a series of serious environmental problems. A full understanding of the N2O formation mechanism is essential to suppress the N2O emission during the low-temperature NH3-SCR, and requires an intensive study of this heterogeneous catalysis process. In this study, we investigated the reaction between NH3 and NO over a Pd/CeO2 catalyst in the absence of O2, using X-ray photoelectron spectroscopy, NH3-temperature-programmed desorption, NO-temperature-programmed desorption, and in-situ Fourier-transform infrared spectroscopy. Our results indicate that the N2O formation mechanism is reaction-temperature-dependent. At temperatures below 250 ℃, the dissociation of HON, which is produced from the reaction between surface H· adatoms and adsorbed NO, is the key process for N2O formation. At temperatures above 250 ℃,the reaction between NO and surface N·, which is produced by NO dissociation, is the only route for N2O formation, and the dissociation of NO is the rate-determining step. Under optimal reaction conditions, a high performance with nearly 100% NO conversion and 100% N2 selectivity could be achieved. These results provide important information to clarify the mechanism of N2O formation and possible suppression of N2 O emission during low-temperature NH3-SCR.展开更多
CeO2-ZeO2 solid solutions are extensively used as oxygen storage promoters in the current automotive three-way catalysts. High thermal stability of the textural properties is one of the most important requirements for...CeO2-ZeO2 solid solutions are extensively used as oxygen storage promoters in the current automotive three-way catalysts. High thermal stability of the textural properties is one of the most important requirements for practical application since temperatures up to 1273 K are easily experienced by these materials under real working conditions. In the present paper, we investigated how hydrothermal treatments applied to cakes of doped and undoped ZrO2-rich CeO2-ZrO2 precursors might improve the thermal stability of the final CeO2-ZrO2 solid solution. A rationale was developed that allowed to correlate the morphology of the hydrothermaUy treated cake with the thermal stability at 1273 K of the final product, which did not depend on the composition of the mixed oxides.展开更多
Nickel catalysts supported on CeO2-ZrO2-CeO2,ZrO2-Al2O3 and Al2O3 were prepared and characterized by means of X-ray diffraction(XRD),BET areas,H2 temperature-programmed reduction(H2-TPR),and X-ray photoelectron sp...Nickel catalysts supported on CeO2-ZrO2-CeO2,ZrO2-Al2O3 and Al2O3 were prepared and characterized by means of X-ray diffraction(XRD),BET areas,H2 temperature-programmed reduction(H2-TPR),and X-ray photoelectron spectroscopy(XPS).Through the test of catalytic partial oxidation of methane(CPOM),Ni/CeO2-ZrO2-Al2O3 displayed the highest activity,which resulted from its largest BET area and best NiO dispersion.Furthermore,Ni/CeO2-ZrO2-Al2O3 maintained a long-time stability in CPOM,which was attributed to its best coking resistance among all the prepared catalysts.展开更多
基金supported by National Natural Science Foundation of China(51202116)Ministry of Science and Technology,China(2010CB732304,2013AA065302)
摘要Praseodymium (Pr) was impregnated to CeO2-ZrO2 solid solution by an impregnation method. The as-obtained Pr modi- fied CeO2-ZrO2 was impregnated with 1 wt.% Pd to prepare the catalysts. The structure and reducibility of the fresh and hydrother- really aged catalysts were characterized by X-ray diffraction (XRD), Raman, X-ray photoelectron spectroscopy (XPS), CO chemi- sorption and H2 temperature-programmed reduction (H2-TPR). The oxygen storage capacity (OSC) was evaluated with CO serving as probe gas. Effects of impregnated Pr on the structure and oxygen storage capacity of catalysts were investigated. The results showed that the aged Pr-impregnated samples had much higher OSC and better reducibility than the unmodified ones. The scheme of structural evolutions of the catalysts with and without Pr was also established. Partial of the impregnated Pr diffused into the bulk of CeO2-ZrO2 during ageing, which inhibited the sintering, and increased the amount of oxygen vacancies in CeO2-ZrO2 support. Furthermore, those impregnated Pr species which covered on the surface of the support obstructed the strong metal-support interaction between Pd and Ce so as to reduce the encapsulation of Pd as well as the back spill-over of the oxygen during the catalytic process.
基金Project supported by National Natural Science Foundation of China (20773090, 20803049)the Specialized Research Fund for the Doctoral Program of Higher Education (20070610026, 200806100009)
摘要Ce-Zr-Al-Nd2O3 (CZAN) support materials were prepared by co-precipitation and impregnation methods, respectively. They were characterized by X-ray diffTaction (XRD), low temperature nitrogen adsorption-desorption, oxygen pulsing technique, H2-temperamre programmed reduction (H2-TPR) and X-ray photoelectron spectroscopy (XPS). The Pd-only three-way catalysts (Pd-TWC) supported on these materials were prepared by incipient wetness method and studied by activity tests. The results demonstrated that the CZAN supports obtained by the two methods showed better structural, textural and redox properties than the CZA without Nd2O3, and the addition of Nd203 improved the catalytic activity of TWC. Especially, the CZAN-i support prepared by impregnation method had better thermal stability and redox property. Meanwhile, the Pd/CZAN-i catalyst exhibited the best catalytic performance. XPS measurements indicated that the Nd-modified samples possessed more Ce3+ and oxygen vacancies on the surface of samples, which led to a better redox property. The excellent redox property of support materials helped to improve the catalytic activity of TWC.
基金supported by the National Natural Science Foundation of China(21173153)National Hi-tech Research and Development Program of China(863)(2015AA034603)Opening Project of Key Laboratory of Green Chemistry of Sichuan Institutes of Higher Education,China(LYJ1407)~~
基金Project supported by the National High Technology Research and Development Program of China (863 Program,2006AA06Z347)the Specialized Research Fund for the Doctoral Program of Higher Education (20070610026)
摘要The Pd-only catalysts for motorcycle were prepared by impregnating CeO2-ZrO2-Al2O3 and CeO2-ZrO2+Al2O3 with PdCl2 aqueous solution and characterized by X-ray diffraction (XRD), oxygen storage capacity (OSC) and H2-temperature-programmed reduction (H2-TPR) methods. The XRD result indicated that the CeO2-ZrO2-Al2O3 compound prepared by co-precipitation formed a single solid solution and had good thermal stability, and Pd phase was not observed in all catalysts. The TPR results showed that the reduction temperature of Pd/CeO2-ZrO2-Al2O3 catalyst was lower than that of Pd/CeO2-ZrO2+Al2O3 catalyst whether they were fresh or aged catalysts. The Pd/CeO2-ZrO2-Al2O3 exhibited high three-way catalytic activity at low temperature, high thermal stability, and wide working window, suggesting a great potential for applications.
基金the National Natural Science Foundation of China(20773090)the Specialized Research Fund for the Doctoral Program of Higher Education of China(20070610026,200806100009)
摘要The catalytic behaviors of Pd(1.4 wt%)catalysts supported on CeO2-ZrO2-La2O3 mixed oxides with different Ce/Zr molar ratios were investigated for methanol decomposition.Nitrogen adsorption-desorption(BET),X-ray photoelectron spectroscopy(XPS),H2 temperature-programmed reduction(H2-TPR),X-ray diffraction(XRD)and Pd dispersion analysis were used for their characterization.Pd/Cc0.76Zro.18 La0.06O1.97 catalyst showed the highest BET surface area,best Pd dispersion capability and strongest metal-support interaction.Moreover,XPS showed that there was lattice defect oxygen or mobile oxygen.According to the result of O 1s measurements the lattice defect oxygen or mobile oxygen helped to maintain Pd in a partly oxidized state and increased the activity for methanol decomposition.The Pd/Ce0.76Zr0.18La0.0601.97 catalyst exhibited the best activity.A 100%conversion of methanol was achieved at around 260°C,which was about 20-40°C lower than other catalysts.
基金Project supported by the National Natural Science Foundation of China(21377048,21307047)the Opening Project of Key Laboratory of Green Catalysis of Sichuan Institutes of High Education(LYJ1309)
摘要A series of CeO2-ZrO2-WO3 catalysts for the selective catalytic reduction (SCR) of NO with NH3 were prepared by hydrothermal method. The influence of calcination temperature on the catalytic activity, microstructure, surface acidity and redox behavior of CeO2-ZrO2-WO3 catalyst was investigated using various characterization methods. It was found that the CeO2-ZrO2-WO3 catalyst calcined at 600 ℃ showed the best catalytic performance and excellent N2 selectivity, and yielded more than 90% NO conversion in a wide temperature range of 250-500 ℃ with a space velocity (GHSV) of 60000 131. As the calcination temperature was increased from 400 to 600 ℃, the NO conversion obviously increased, but decreased at higher calcination temperature. The results implied that the higher surface area, the strongest synergistic interaction, the superior redox property and the highly dispersed or amorphous WO3 species contributed to the excellent SCR activity of the CeO2-ZrO2-WO3 catalyst calcined at 600℃.
基金Project supported by the "863 Project" (2009AA06Z304 and 2009AA064801)
摘要Nickel and sulfate co-modified CeO2-ZrO2 catalysts were prepared by sol-gel method. The catalysts were characterized by XRD, FTIR, XPS, NH3 chemisorption and NH3-SCR activity tests. The results showed that the enhanced acidity of CeO2-ZrO2 catalysts by nickel and sulfate co-modification was responsible for the broadened temperature window and improved the selectivity to N2 in NH3-SCR deNOx. The introduction of nickel to CeO2-ZrO2 solid solutions resulted in more Ce3+ on surface of catalyst, leading to an in...
基金supported by National Natural Science Foundation of China(51474133,21407084)Talent Incubation Funding of School of Materials and Metallurgy(2014CY012)
摘要The electrocatalytic activity and stability of Pt/C catalyst modified by using CeO_2-ZrO_2 mixed oxides for the alcohols electrochemical oxidation as probes were investigated. The catalyst samples were characterized by X-ray diffraction(XRD) and scanning electron microscopy(SEM). The electrochemical properties were measured by a three electrode system on electrochemical workstation(IVIUM). The results showed that the presence of CeO_2-ZrO_2 might be associated with the presence of Pt, which indicated that possibly there was synergistic effect between CeO_2-ZrO_2 and Pt nanoparticles. The electrocatalytic activity and stability of Pt-MO_x/C(M=Ce, Zr) for methanol and ethanol oxidation was better than that of Pt-CeO_2/C, which was attributed to that CeO_2-ZrO_2 composited oxides enhanced oxygen mobility and promoted oxygen storage capacity(OSC). Furthermore, the best performance was found when the molar ratio of CeO_2 to ZrO_2 was 2:1 for the oxidation of methanol and ethanol. The forward peak current density of Pt-MO_x/C(M=Ce, Zr, Ce:Zr=2:1) towards the methanol electrooxidation was about 3.8 times that of Pt-CeO_2/C. Pt-MO_x/C(M=Ce, Zr) appeared to be a promising and less expensive methanol oxidation anode catalyst.
摘要CeO2-based oxygen materials were prepared with co-precipitation method and characterized via Brunauer-Emmet Teller(BET)method,X-ray diffraction(XRD)and temperature-programmed reduction(H2-TPR).This paper revealed that three CeO2-based oxygen storage materials are all forming homogeneous solid solution.Among the samples,CeO2-ZrO2-Al2O3(CZA)has the best textural properties and excellent thermal stability.The specific surface area and pore volume of aged CZA are 90 m2/g and 0.29 mL/g.We proposed a viewpoint:Al3+ might insert among the interspace of fluorite structure or highly dispersal in solid solutions.
基金supported by the Ministry of Science and Technology,China(No.2009AA064801,2010CB732304)
摘要Potassium-modified ceria-zirconia catalyst was synthesized by wetness impregnation method.The ageing treatment was performed in static air at 800℃for 20 hr to evaluate the thermal stability of the catalyst.The catalysts were characterized by X-ray diffraction,BET surface area,oxygen storage capacity,NOx-temperature programmed desorption and soot-temperature programmed oxidation measurements.By introduction of potassium,the maximum soot oxidation rate temperature(Tin)of the ceria-zirconia based catalyst decreased from 525 to 428℃in the presence of NO under a loose contact mode.The shift of Tm of the K-modified catalyst after ageing is only 15℃.The enhanced activity of the aged catalyst mainly lies in the promotional effect of potassium on the NOx/oxygen storage capacity as well as the soot-catalyst contact.
基金support of the National Key Research and Development Program of China(2017YFB0310403)the National Natural Science Foundation of China(51872260,51390474,91645103)+2 种基金the Ministry of Science and Technology of China(2016YFE0105700)the Environmentally Sustainable Management of Medical Wastes in China(C/V/S/10/251)the Zhejiang Provincial Natural Science Foundation of China(Z4080070,LD19B030001)~~
摘要N2O is a major by-product emitted during low-temperature selective catalytic reduction of NO with NH3(NH3-SCR), which causes a series of serious environmental problems. A full understanding of the N2O formation mechanism is essential to suppress the N2O emission during the low-temperature NH3-SCR, and requires an intensive study of this heterogeneous catalysis process. In this study, we investigated the reaction between NH3 and NO over a Pd/CeO2 catalyst in the absence of O2, using X-ray photoelectron spectroscopy, NH3-temperature-programmed desorption, NO-temperature-programmed desorption, and in-situ Fourier-transform infrared spectroscopy. Our results indicate that the N2O formation mechanism is reaction-temperature-dependent. At temperatures below 250 ℃, the dissociation of HON, which is produced from the reaction between surface H· adatoms and adsorbed NO, is the key process for N2O formation. At temperatures above 250 ℃,the reaction between NO and surface N·, which is produced by NO dissociation, is the only route for N2O formation, and the dissociation of NO is the rate-determining step. Under optimal reaction conditions, a high performance with nearly 100% NO conversion and 100% N2 selectivity could be achieved. These results provide important information to clarify the mechanism of N2O formation and possible suppression of N2 O emission during low-temperature NH3-SCR.
基金PRIN 2006, "Caratterizzazione spettroscopica e morfologica di Me-POSS eterogeneizzati", MEL Chemicals
摘要CeO2-ZeO2 solid solutions are extensively used as oxygen storage promoters in the current automotive three-way catalysts. High thermal stability of the textural properties is one of the most important requirements for practical application since temperatures up to 1273 K are easily experienced by these materials under real working conditions. In the present paper, we investigated how hydrothermal treatments applied to cakes of doped and undoped ZrO2-rich CeO2-ZrO2 precursors might improve the thermal stability of the final CeO2-ZrO2 solid solution. A rationale was developed that allowed to correlate the morphology of the hydrothermaUy treated cake with the thermal stability at 1273 K of the final product, which did not depend on the composition of the mixed oxides.
基金Project supported by State Key Fundamental Research Project(G1999022400)
摘要Nickel catalysts supported on CeO2-ZrO2-CeO2,ZrO2-Al2O3 and Al2O3 were prepared and characterized by means of X-ray diffraction(XRD),BET areas,H2 temperature-programmed reduction(H2-TPR),and X-ray photoelectron spectroscopy(XPS).Through the test of catalytic partial oxidation of methane(CPOM),Ni/CeO2-ZrO2-Al2O3 displayed the highest activity,which resulted from its largest BET area and best NiO dispersion.Furthermore,Ni/CeO2-ZrO2-Al2O3 maintained a long-time stability in CPOM,which was attributed to its best coking resistance among all the prepared catalysts.