The nano ZrO2-supported copper-based catalysts for methane combustion were investigated by means of N2 adsorption, TEM, XRD, H2-TPR techniques and the test of methane oxidation. Two kinds of ZrO2 were used as support,...The nano ZrO2-supported copper-based catalysts for methane combustion were investigated by means of N2 adsorption, TEM, XRD, H2-TPR techniques and the test of methane oxidation. Two kinds of ZrO2 were used as support, one (ZrO2-1) was obtained from the commercial ZrO2 and the other (ZrO2-2) was issued from the thermal decomposition of zirconium nitrate. It was found that the CuO/ZrO2-2 catalyst was more active than CuO/ZrO2-1. N2 adsorption, H2-TPR and XRD measurements showed that larger surface area, better reduction property, presence of tetragonal ZrO2 and higher dispersion of active component for CuO/ZrO2-2 than that of CuO/ZrO2-1. These factors could be the dominating reasons for its higher activity for methane combustion.展开更多
A solid superacid catalyst Pt-SO42-/ZrO2-A12O3 for n-pentane isomerization, was prepared by incipient-wetness impregnation. Preparetion conditions, namely, calcination temperature, concentration of sulfuric acid solut...A solid superacid catalyst Pt-SO42-/ZrO2-A12O3 for n-pentane isomerization, was prepared by incipient-wetness impregnation. Preparetion conditions, namely, calcination temperature, concentration of sulfuric acid solution used in impregnation and Al2O3 concentration, were varied to investigate the effects on catalytic performance of Pt-SO42-/ZrO2-A12O3. The results showed that the PtSZA catalyst exhibited excellent catalytic performance for n-pentane isomerization. Under optimized preparation conditions of calcination temperature of 650°C, reaction time for 3 h, concentration of sulfuric acid solution for 0.5 mol/L, 30% of Al2O3 concentration and 0.3% of Pt concentration, the n-pentane conversion and isopentane selectivity of Pt-SO42-/ZrO2-A12O3 could reach up to 62.17% and 91.60%, respectively.展开更多
A novel solid superacid catalyst S2O8^2-/ZrO2-CeO2 was prepared by a coprecipitation method and characterized by means of XRD FTIR, BET, TEM and DSC/TG analysis methods. The results indicated that incorporation of app...A novel solid superacid catalyst S2O8^2-/ZrO2-CeO2 was prepared by a coprecipitation method and characterized by means of XRD FTIR, BET, TEM and DSC/TG analysis methods. The results indicated that incorporation of appropriate amounts of Ce into the catalyst was beneficial to the formation of sole tetragonal ZrO2 and effectively prevented from the formation of monoclinic ZrO〉 and restrained the loss of sulfated species. XRD revealed the presence of tetragonal Ce0.16Zr0.84O2phase in the case of S2O8^2-/ZrO2-CeO2 calcined above 500 ℃. Catalytic activities of S2O8^2-/ZrO2-CeO2 for the esterification of lactic acid with n-butanol was studied. The results showed that the optimum conditions were as follows: calcination temperature of the catalyst 600 ℃, n(lactic acid):n(n-butyl alcohol)=1.0:3.0, w(S2O8^2-/ZrO2- CeO2)=12.0%, reaction temperature 145 ℃, and reaction time 2 h. The esterification efficiency of lactic acid was about 96.6%.展开更多
Ni/ZrO2 catalysts were prepared by the incipient-wetness impregnation method and were investigated in activity and selectivity for the selective catalytic methanation of CO in hydrogen-rich gases with more than 20 vol...Ni/ZrO2 catalysts were prepared by the incipient-wetness impregnation method and were investigated in activity and selectivity for the selective catalytic methanation of CO in hydrogen-rich gases with more than 20 vol% CO2. The result showed that Ni loadings significantly influenced the performance of Ni/ZrO2 catalyst. The 1.6 wt% Ni loading catalyst exhibited the highest catalytic activity among all the catalysts in the selective methanation of CO in hydrogen-rich gas. The outlet concentration of CO was less than 20 ppm with the hydrogen consumption below 7%, at a gas-hourly-space velocity as high as 10000 h-1 and a temperature range of 260 °C to 280 °C. The X-ray diffraction (XRD) and temperature programmed reduction (TPR) measurements showed that NiO was dispersed thoroughly on the surface of ZrO2 support if Ni loading was under 1.6 wt%. When Ni loading was increased to 3 wt% or above, the free bulk NiO species began to assemble, which was not favorable to increase the selectivity of the catalyst.展开更多
Amorphous Ni-Ru-B/ZrO2 catalyst was prepared by the means of chemical reduction, and selective CO methanation as a strategy for CO removal in fuel processing applications was investigated over the amorphous Ni-Ru-B/Zr...Amorphous Ni-Ru-B/ZrO2 catalyst was prepared by the means of chemical reduction, and selective CO methanation as a strategy for CO removal in fuel processing applications was investigated over the amorphous Ni-Ru-B/ZrO2 catalyst. The result showed that, at the temperature of 210-230 ℃, the catalyst was shown to be capable of reducing CO in a hydrogen-rich reformate to less than 10 ppm, while keeping the CO2 conversion below 1.55% and the hydrogen consumption below 6.50%. ?2009 Xin Fa Dong. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.展开更多
A novel nanosized amorphous Ru-Fe-B/ZrO2 alloy catalyst for benzene selective hydrogenation to cyclohexene was investigated. The superior properties of this catalyst were attributed to the combination of the nanosize ...A novel nanosized amorphous Ru-Fe-B/ZrO2 alloy catalyst for benzene selective hydrogenation to cyclohexene was investigated. The superior properties of this catalyst were attributed to the combination of the nanosize and the amorphous character as well as to its textural character. In addition, the concentration of zinc ions, the content of ZrO2 in the slurry, and the pretreatment of the catalyst were found to be effective in improving the activity and the selectivity of the catalyst.展开更多
Amorphous Ni-Ru-B/ZrO2 catalysts were prepared by chemical reduction method. The effects of Ni-Ru-B loading and Ru/Ni mole ratio on the catalytic performance for selective CO methanation from reformed fuel were studie...Amorphous Ni-Ru-B/ZrO2 catalysts were prepared by chemical reduction method. The effects of Ni-Ru-B loading and Ru/Ni mole ratio on the catalytic performance for selective CO methanation from reformed fuel were studied, and the catalysts were characterized by BET, ICP, XRD and TPD. The results showed that Ru strongly affected the catalytic activity and selectivity by increasing the thermal stability of amorphous structure, promoting the dispersion of the catalyst particle, and intensifying the CO adsorption. For the catalysts with Ru/Ni mole ratio under 0.15, the CO methanation conversion and selectivity increased significantly with the increasing Ru/Ni mole ratio. Among all the catalysts investigated, the 30 wt% Ni-Ru-B loading amorphous Ni61Ru9B30/ZrO2 catalyst with 0.15 Ru/Ni mole ratio presented the best catalytic performance, over which higher than 99.9% of CO conversion was obtained in the temperature range of 230℃-250℃, and the CO2 conversion was kept under the level of 0.9%.展开更多
We report Ni/LaHA@ZrO2catalysts prepared by a facile modified successive adsorption and reaction method for CO methanation.N2adsorption,X‐ray diffraction,transmission electron microscopy,scanning electron microscopy,...We report Ni/LaHA@ZrO2catalysts prepared by a facile modified successive adsorption and reaction method for CO methanation.N2adsorption,X‐ray diffraction,transmission electron microscopy,scanning electron microscopy,thermogravimetric analysis,H2temperature‐programmed reduction,H2temperature‐programmed desorption,X‐ray photoelectron spectroscopy,thermogravimetric analysis,and inductively coupled plasma atomic emission spectrometry were used to characterize the samples.The results indicated that the ZrO2nanoparticles were distributed over the surface of the Ni/LaHA@ZrO2catalyst and even partially covered some Ni particles,resulting in the coating exerting a confinement effect.The excess ZrO2had an adverse effect on the enhancement of CO conversion because of the coverage of the surface Ni particles;however,the Ni/LaHA@ZrO2catalyst displayed much higher CH4selectivity than Ni/LaHA because of the activation of the byproduct CO2molecules by ZrO2species.Therefore,even though20Ni/LaHA@ZrO2‐5exhibited similar CO conversion as20Ni/LaHA,the use of the former resulted in a higher CH4yield than the use of the latter.A107‐h‐lifetime test revealed that the Ni/LaHA@ZrO2catalyst was highly stable with superior anti‐sintering and anti‐coking properties because of its coating structure and the promoter effect of ZrO2.展开更多
Amorphous Ni-B/ZrO2 catalysts were prepared by coprecipitation-chemical reduction with KBH4 aqueous solution,and various crystalline phase ZrO2(amorphous-ZrO2,tetragonal-ZrO2 and monoclinic-ZrO2) supported Ni-B cataly...Amorphous Ni-B/ZrO2 catalysts were prepared by coprecipitation-chemical reduction with KBH4 aqueous solution,and various crystalline phase ZrO2(amorphous-ZrO2,tetragonal-ZrO2 and monoclinic-ZrO2) supported Ni-B catalysts were obtained by thermal treatment in 5%H2-N2 stream at different temperature.The effect of ZrO2 polymorphs and the treatment temperature on the catalytic performance for the CO selective methanation were investigated,and the catalysts were characterized by N2 physisorption,Powder X-ray diffraction(XRD), Temperature-Programmed Desorption(CO-TPD and H2-TPD),and Differential Scanning Calorimeter(DSC).The treatment temperature affected strongly the crystalline structure of ZrO2,and the CO methanation activity and selectivity of the Ni-B/ZrO2 catalysts were significantly influenced by the crystalline phase of ZrO2.Of the three forms of ZrO2 polymorphs(amorphou-ZrO2,tetragonal-ZrO2 and monoclinic-ZrO2),the amorphous-ZrO2 supported nickle catalyst showed highest CO methanation activity,attributing in large part to the largest specific surface area and the optimum CO/H2 absorption intensity of the Ni-B/amorphous-ZrO2 catalyst.展开更多
ZrO2-MnO2-ZnO supports were prepared by the co-precipitation method,and then Ni-Na/ZrO2-MnO2-ZnO catalysts were prepared by the impregnation method.In this paper,the reactions to synthesize methyl isopropyl ketone and...ZrO2-MnO2-ZnO supports were prepared by the co-precipitation method,and then Ni-Na/ZrO2-MnO2-ZnO catalysts were prepared by the impregnation method.In this paper,the reactions to synthesize methyl isopropyl ketone and diethyl ketone by the one-step synthesis method over this catalyst were studied,and meanwhile,the impact of the catalyst preparation conditions and the reaction conditions on catalyst performance was also investigated.It was observed that under the conditions when Ni loading was 25%,calcination temperature was 400℃ and reduction temperature was 410℃,this catalyst had good catalytic performance on the reaction.The suitable reaction conditions were achieved:reaction temperature was 400℃;reaction at atmospheric pressure;liquid hourly space velocity of raw material of 0.5 h 1 ;and the molar ratio of(methanol)/(methyl ethyl ketone)/(water) was equal to 1/1/1.Under such conditions,the conversion of methyl ethyl ketone could achieve 41.7%,and the overall selectivity of methyl isopropyl ketone and diethyl ketone could achieve 83.3%,which was comparable to the conversion of 38.1% and the selectivity of 82.2% achieved by using palladium as the active material.The good stability made this catalyst have good prospects for industrial application.展开更多
Nano ZrO2 and MgO-ZrO2 were prepared by a self-assembly route and were employed as the support for Ni catalysts used in hydrogen production from glycerol reforming in supercritical water (SCW). The reforming experim...Nano ZrO2 and MgO-ZrO2 were prepared by a self-assembly route and were employed as the support for Ni catalysts used in hydrogen production from glycerol reforming in supercritical water (SCW). The reforming experiments were conducted in a tubular fixed-bed flow reactor over a temperature range of 600-800 ℃. The influences of process variables such as temperature, contact time, and water to glycerol ratio on hydrogen yield were investigated and the catalysts were charactered by ICP, BET, XRD and SEM. The results showed that high hydrogen yield was obtained from glycerol by reforming in supercritical water over the Ni/MgO-ZrO2 catalysts in a short contact time. The MgO in the catalyst showed significant promotion effect for hydrogen production likely due to the formation of the alkaline active site. Even when the glycerol feed concentration was up to 45 wt%, glycerol was completely gasified and transfered to the gas products containing hydrogen, carbon dioxide, and methane along with small amounts of carbon monoxide. At a diluted feed concentration of 5 wt%, near theoretical yield of 7 mole of H2/mol of glycerol could be obtained.展开更多
With the help of the ceramic foam research efforts and preparation techniques, the ZrO2 polycrystalline ceramic foam catalyst was synthesized, and its characteristics, including the crystal structure, the phase compos...With the help of the ceramic foam research efforts and preparation techniques, the ZrO2 polycrystalline ceramic foam catalyst was synthesized, and its characteristics, including the crystal structure, the phase composition, the acid–base properties, and the microstructure, were analyzed by XRD, SEM, Py-IR, and BET techniques. The performance of the ZrO2 polycrystalline ceramic foam catalyst in a tubular reactor was investigated via biodiesel synthesis using S. wilsoniana oil and methanol. The effects of reaction conditions(i.e., reaction temperature, reaction pressure, and volume ratio of methanol to S. wilsoniana oil) on transesterification efficiency were investigated, and the reaction conditions were optimized using RSM. The optimum reaction temperature, reaction pressure, and volume ratio of methanol to S. wilsoniana oil were determined to be 290 ℃, 10 MPa, and 4:1, respectively. Under this condition, the FAME content in the product oil reached 98.38%. The performance of the ZrO2 polycrystalline ceramic foam catalyst synthesized in this work for biodiesel synthesis from S. wilsoniana oil with a moisture content of 7.1% and an acid value of 130.697 mg KOH/g was examined, and the FAME content in the product oil was found to be 93% and 97.67%, respectively. The FAME content in the product oil exceeded 97% after five consecutive cycles(12 h per cycle of use) of the catalyst. The proposed catalyst represents a new type of solid catalyst with excellent acid resistance, water resistance, esterification efficiency, and catalytic stability.展开更多
The intensity of the signal(g=1.974)resulted from Zr+ ion on the surface or ZrO2 catalyst, increased with the calcination temperature and time, but that or the signal (g=2.003)resulted from F+s centers (surface oxygen...The intensity of the signal(g=1.974)resulted from Zr+ ion on the surface or ZrO2 catalyst, increased with the calcination temperature and time, but that or the signal (g=2.003)resulted from F+s centers (surface oxygen ion vacancies with a single trapped electron) decreased and finally disappeared at 550℃.展开更多
A S 2O 2- 8/ZrO 2 Al 2O 3 type solid superacid catalyst was prepared from ZrOCl 2·8H 2O, AlCl 3· 6H 2O and (NH 4) 2S 2O 8 by coprecipitation, maceration and calcination processes. Their crystal structures an...A S 2O 2- 8/ZrO 2 Al 2O 3 type solid superacid catalyst was prepared from ZrOCl 2·8H 2O, AlCl 3· 6H 2O and (NH 4) 2S 2O 8 by coprecipitation, maceration and calcination processes. Their crystal structures and acidities were determined by XRD and Hammett method, respectively. The activity of the catalyst was studied as function of Al 2O 3 content, calcination temperature and time in the esterification of acetic acid with butanol, and a conversion of 96 5% was obtained. The catalyst gave also higher yields in syntheses of ketals and acetals: cyclohexanone ethylene ketal(86 2%), acetophenone ethylene ketal(78 5%), acetylacetic ester ketal(88 5%), benzaldehyde glycol acetal(76 3%). The chemical structures of the products were confirmed by IR spectra.展开更多
The preparation of peroxodisulfated zirconia titania(PSZT) solid super acid has been investigated as function of molar ratio of Ti to Zr, impregnation time, calcination time and temperature in esterification of maleic...The preparation of peroxodisulfated zirconia titania(PSZT) solid super acid has been investigated as function of molar ratio of Ti to Zr, impregnation time, calcination time and temperature in esterification of maleic anhydride with n octanol. The highest yield of dioctyl maleate was 98 2% at the optimum reaction conditions.展开更多
文摘The nano ZrO2-supported copper-based catalysts for methane combustion were investigated by means of N2 adsorption, TEM, XRD, H2-TPR techniques and the test of methane oxidation. Two kinds of ZrO2 were used as support, one (ZrO2-1) was obtained from the commercial ZrO2 and the other (ZrO2-2) was issued from the thermal decomposition of zirconium nitrate. It was found that the CuO/ZrO2-2 catalyst was more active than CuO/ZrO2-1. N2 adsorption, H2-TPR and XRD measurements showed that larger surface area, better reduction property, presence of tetragonal ZrO2 and higher dispersion of active component for CuO/ZrO2-2 than that of CuO/ZrO2-1. These factors could be the dominating reasons for its higher activity for methane combustion.
文摘A solid superacid catalyst Pt-SO42-/ZrO2-A12O3 for n-pentane isomerization, was prepared by incipient-wetness impregnation. Preparetion conditions, namely, calcination temperature, concentration of sulfuric acid solution used in impregnation and Al2O3 concentration, were varied to investigate the effects on catalytic performance of Pt-SO42-/ZrO2-A12O3. The results showed that the PtSZA catalyst exhibited excellent catalytic performance for n-pentane isomerization. Under optimized preparation conditions of calcination temperature of 650°C, reaction time for 3 h, concentration of sulfuric acid solution for 0.5 mol/L, 30% of Al2O3 concentration and 0.3% of Pt concentration, the n-pentane conversion and isopentane selectivity of Pt-SO42-/ZrO2-A12O3 could reach up to 62.17% and 91.60%, respectively.
基金supported by the Science and Technique Foundation of Shaaxi Province of China (2008K07-32)the Foundation of Shaanxi Educa- tional Committee of China (08JK228)the Graduate Innovation Fund of Shaanxi University of Science and Technology
文摘A novel solid superacid catalyst S2O8^2-/ZrO2-CeO2 was prepared by a coprecipitation method and characterized by means of XRD FTIR, BET, TEM and DSC/TG analysis methods. The results indicated that incorporation of appropriate amounts of Ce into the catalyst was beneficial to the formation of sole tetragonal ZrO2 and effectively prevented from the formation of monoclinic ZrO〉 and restrained the loss of sulfated species. XRD revealed the presence of tetragonal Ce0.16Zr0.84O2phase in the case of S2O8^2-/ZrO2-CeO2 calcined above 500 ℃. Catalytic activities of S2O8^2-/ZrO2-CeO2 for the esterification of lactic acid with n-butanol was studied. The results showed that the optimum conditions were as follows: calcination temperature of the catalyst 600 ℃, n(lactic acid):n(n-butyl alcohol)=1.0:3.0, w(S2O8^2-/ZrO2- CeO2)=12.0%, reaction temperature 145 ℃, and reaction time 2 h. The esterification efficiency of lactic acid was about 96.6%.
基金the National Natural Science Foundation of China (20576023)the Guangdong Province Natural Science Foundation (06025660)
文摘Ni/ZrO2 catalysts were prepared by the incipient-wetness impregnation method and were investigated in activity and selectivity for the selective catalytic methanation of CO in hydrogen-rich gases with more than 20 vol% CO2. The result showed that Ni loadings significantly influenced the performance of Ni/ZrO2 catalyst. The 1.6 wt% Ni loading catalyst exhibited the highest catalytic activity among all the catalysts in the selective methanation of CO in hydrogen-rich gas. The outlet concentration of CO was less than 20 ppm with the hydrogen consumption below 7%, at a gas-hourly-space velocity as high as 10000 h-1 and a temperature range of 260 °C to 280 °C. The X-ray diffraction (XRD) and temperature programmed reduction (TPR) measurements showed that NiO was dispersed thoroughly on the surface of ZrO2 support if Ni loading was under 1.6 wt%. When Ni loading was increased to 3 wt% or above, the free bulk NiO species began to assemble, which was not favorable to increase the selectivity of the catalyst.
基金supported by the National Natural Science Foundation of China(No.20576023)the Guangdong Province Natural Science Foundation(No.06025660).
文摘Amorphous Ni-Ru-B/ZrO2 catalyst was prepared by the means of chemical reduction, and selective CO methanation as a strategy for CO removal in fuel processing applications was investigated over the amorphous Ni-Ru-B/ZrO2 catalyst. The result showed that, at the temperature of 210-230 ℃, the catalyst was shown to be capable of reducing CO in a hydrogen-rich reformate to less than 10 ppm, while keeping the CO2 conversion below 1.55% and the hydrogen consumption below 6.50%. ?2009 Xin Fa Dong. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.
文摘A novel nanosized amorphous Ru-Fe-B/ZrO2 alloy catalyst for benzene selective hydrogenation to cyclohexene was investigated. The superior properties of this catalyst were attributed to the combination of the nanosize and the amorphous character as well as to its textural character. In addition, the concentration of zinc ions, the content of ZrO2 in the slurry, and the pretreatment of the catalyst were found to be effective in improving the activity and the selectivity of the catalyst.
基金supported by the National Natural Science Foundation of China (No: 20576023)the Guangdong Province Natural Science Foundation(No: 06025660)the Natural Science Foundation of Zhongkai University of Agriculture and Engineering (G3100026)
文摘Amorphous Ni-Ru-B/ZrO2 catalysts were prepared by chemical reduction method. The effects of Ni-Ru-B loading and Ru/Ni mole ratio on the catalytic performance for selective CO methanation from reformed fuel were studied, and the catalysts were characterized by BET, ICP, XRD and TPD. The results showed that Ru strongly affected the catalytic activity and selectivity by increasing the thermal stability of amorphous structure, promoting the dispersion of the catalyst particle, and intensifying the CO adsorption. For the catalysts with Ru/Ni mole ratio under 0.15, the CO methanation conversion and selectivity increased significantly with the increasing Ru/Ni mole ratio. Among all the catalysts investigated, the 30 wt% Ni-Ru-B loading amorphous Ni61Ru9B30/ZrO2 catalyst with 0.15 Ru/Ni mole ratio presented the best catalytic performance, over which higher than 99.9% of CO conversion was obtained in the temperature range of 230℃-250℃, and the CO2 conversion was kept under the level of 0.9%.
基金supported by the National Natural Science Foundation of China (21606146)Natural Science Foundation of Shandong Province (ZR2016BB17,2016ZRB01037)+3 种基金Scientific Research Foundation of Shandong University of Science and Technology for Recruited Talents (2016RCJJ005,2016RCJJ006)Government Sponsored Visiting Scholar Foundation of Shandong University of Science and Technology (2016)Qingdao Postdoctoral Applied Research Project (2015202)China National Coal Association Science and Technology Research Program (MTKJ2016-266)~~
文摘We report Ni/LaHA@ZrO2catalysts prepared by a facile modified successive adsorption and reaction method for CO methanation.N2adsorption,X‐ray diffraction,transmission electron microscopy,scanning electron microscopy,thermogravimetric analysis,H2temperature‐programmed reduction,H2temperature‐programmed desorption,X‐ray photoelectron spectroscopy,thermogravimetric analysis,and inductively coupled plasma atomic emission spectrometry were used to characterize the samples.The results indicated that the ZrO2nanoparticles were distributed over the surface of the Ni/LaHA@ZrO2catalyst and even partially covered some Ni particles,resulting in the coating exerting a confinement effect.The excess ZrO2had an adverse effect on the enhancement of CO conversion because of the coverage of the surface Ni particles;however,the Ni/LaHA@ZrO2catalyst displayed much higher CH4selectivity than Ni/LaHA because of the activation of the byproduct CO2molecules by ZrO2species.Therefore,even though20Ni/LaHA@ZrO2‐5exhibited similar CO conversion as20Ni/LaHA,the use of the former resulted in a higher CH4yield than the use of the latter.A107‐h‐lifetime test revealed that the Ni/LaHA@ZrO2catalyst was highly stable with superior anti‐sintering and anti‐coking properties because of its coating structure and the promoter effect of ZrO2.
基金Supported by the National Natural Science Foundation of China(21076047)the Natural Science Foundation of Zhongkai University of Agriculture and Engineering(G3100026)
文摘Amorphous Ni-B/ZrO2 catalysts were prepared by coprecipitation-chemical reduction with KBH4 aqueous solution,and various crystalline phase ZrO2(amorphous-ZrO2,tetragonal-ZrO2 and monoclinic-ZrO2) supported Ni-B catalysts were obtained by thermal treatment in 5%H2-N2 stream at different temperature.The effect of ZrO2 polymorphs and the treatment temperature on the catalytic performance for the CO selective methanation were investigated,and the catalysts were characterized by N2 physisorption,Powder X-ray diffraction(XRD), Temperature-Programmed Desorption(CO-TPD and H2-TPD),and Differential Scanning Calorimeter(DSC).The treatment temperature affected strongly the crystalline structure of ZrO2,and the CO methanation activity and selectivity of the Ni-B/ZrO2 catalysts were significantly influenced by the crystalline phase of ZrO2.Of the three forms of ZrO2 polymorphs(amorphou-ZrO2,tetragonal-ZrO2 and monoclinic-ZrO2),the amorphous-ZrO2 supported nickle catalyst showed highest CO methanation activity,attributing in large part to the largest specific surface area and the optimum CO/H2 absorption intensity of the Ni-B/amorphous-ZrO2 catalyst.
基金Supported by the National Science and Technology Support Program Project (2006BAE03B06)
文摘ZrO2-MnO2-ZnO supports were prepared by the co-precipitation method,and then Ni-Na/ZrO2-MnO2-ZnO catalysts were prepared by the impregnation method.In this paper,the reactions to synthesize methyl isopropyl ketone and diethyl ketone by the one-step synthesis method over this catalyst were studied,and meanwhile,the impact of the catalyst preparation conditions and the reaction conditions on catalyst performance was also investigated.It was observed that under the conditions when Ni loading was 25%,calcination temperature was 400℃ and reduction temperature was 410℃,this catalyst had good catalytic performance on the reaction.The suitable reaction conditions were achieved:reaction temperature was 400℃;reaction at atmospheric pressure;liquid hourly space velocity of raw material of 0.5 h 1 ;and the molar ratio of(methanol)/(methyl ethyl ketone)/(water) was equal to 1/1/1.Under such conditions,the conversion of methyl ethyl ketone could achieve 41.7%,and the overall selectivity of methyl isopropyl ketone and diethyl ketone could achieve 83.3%,which was comparable to the conversion of 38.1% and the selectivity of 82.2% achieved by using palladium as the active material.The good stability made this catalyst have good prospects for industrial application.
基金supported by the National Natural Science Foundation (21076047 and 21276054)the Natural Science Foundation of Zhongkai University of Agriculture and Engineering (G3100026)
文摘Nano ZrO2 and MgO-ZrO2 were prepared by a self-assembly route and were employed as the support for Ni catalysts used in hydrogen production from glycerol reforming in supercritical water (SCW). The reforming experiments were conducted in a tubular fixed-bed flow reactor over a temperature range of 600-800 ℃. The influences of process variables such as temperature, contact time, and water to glycerol ratio on hydrogen yield were investigated and the catalysts were charactered by ICP, BET, XRD and SEM. The results showed that high hydrogen yield was obtained from glycerol by reforming in supercritical water over the Ni/MgO-ZrO2 catalysts in a short contact time. The MgO in the catalyst showed significant promotion effect for hydrogen production likely due to the formation of the alkaline active site. Even when the glycerol feed concentration was up to 45 wt%, glycerol was completely gasified and transfered to the gas products containing hydrogen, carbon dioxide, and methane along with small amounts of carbon monoxide. At a diluted feed concentration of 5 wt%, near theoretical yield of 7 mole of H2/mol of glycerol could be obtained.
基金the financial support from the National Natural Science Foundation of China (No. 21266022, No. 21466022)the National High Technology Research and Development Program 863 (2014AA022002, 2012AA101800-03, 2012AA021205-6, 2012AA021704)+1 种基金the Key Programs of the National Laboratory (No. SKLFZZB-201312)the International Science & Technology Cooperation Program of China (2014DFA61040)
文摘With the help of the ceramic foam research efforts and preparation techniques, the ZrO2 polycrystalline ceramic foam catalyst was synthesized, and its characteristics, including the crystal structure, the phase composition, the acid–base properties, and the microstructure, were analyzed by XRD, SEM, Py-IR, and BET techniques. The performance of the ZrO2 polycrystalline ceramic foam catalyst in a tubular reactor was investigated via biodiesel synthesis using S. wilsoniana oil and methanol. The effects of reaction conditions(i.e., reaction temperature, reaction pressure, and volume ratio of methanol to S. wilsoniana oil) on transesterification efficiency were investigated, and the reaction conditions were optimized using RSM. The optimum reaction temperature, reaction pressure, and volume ratio of methanol to S. wilsoniana oil were determined to be 290 ℃, 10 MPa, and 4:1, respectively. Under this condition, the FAME content in the product oil reached 98.38%. The performance of the ZrO2 polycrystalline ceramic foam catalyst synthesized in this work for biodiesel synthesis from S. wilsoniana oil with a moisture content of 7.1% and an acid value of 130.697 mg KOH/g was examined, and the FAME content in the product oil was found to be 93% and 97.67%, respectively. The FAME content in the product oil exceeded 97% after five consecutive cycles(12 h per cycle of use) of the catalyst. The proposed catalyst represents a new type of solid catalyst with excellent acid resistance, water resistance, esterification efficiency, and catalytic stability.
文摘The intensity of the signal(g=1.974)resulted from Zr+ ion on the surface or ZrO2 catalyst, increased with the calcination temperature and time, but that or the signal (g=2.003)resulted from F+s centers (surface oxygen ion vacancies with a single trapped electron) decreased and finally disappeared at 550℃.
文摘A S 2O 2- 8/ZrO 2 Al 2O 3 type solid superacid catalyst was prepared from ZrOCl 2·8H 2O, AlCl 3· 6H 2O and (NH 4) 2S 2O 8 by coprecipitation, maceration and calcination processes. Their crystal structures and acidities were determined by XRD and Hammett method, respectively. The activity of the catalyst was studied as function of Al 2O 3 content, calcination temperature and time in the esterification of acetic acid with butanol, and a conversion of 96 5% was obtained. The catalyst gave also higher yields in syntheses of ketals and acetals: cyclohexanone ethylene ketal(86 2%), acetophenone ethylene ketal(78 5%), acetylacetic ester ketal(88 5%), benzaldehyde glycol acetal(76 3%). The chemical structures of the products were confirmed by IR spectra.
文摘The preparation of peroxodisulfated zirconia titania(PSZT) solid super acid has been investigated as function of molar ratio of Ti to Zr, impregnation time, calcination time and temperature in esterification of maleic anhydride with n octanol. The highest yield of dioctyl maleate was 98 2% at the optimum reaction conditions.