Methanol synthesis from hydrogenation of CO2 is investigated over Cu/ZnO/Al2O3 catalysts prepared by decomposition of M（Cu,Zn）-ammonia complexes （DMAC） at various temperatures.The catalysts were characterized in d...Methanol synthesis from hydrogenation of CO2 is investigated over Cu/ZnO/Al2O3 catalysts prepared by decomposition of M（Cu,Zn）-ammonia complexes （DMAC） at various temperatures.The catalysts were characterized in detail,including X-ray diffraction,N2 adsorption-desorption,N2O chemisorption,temperature-programmed reduction and evolved gas analyses.The influences of DMAC temperature,reaction temperature and specific Cu surface area on catalytic performance are investigated.It is considered that the aurichalcite phase in the precursor plays a key role in improving the physiochemical properties and activities of the final catalysts.The catalyst from rich-aurichalcite precursor exhibits large specific Cu surface area and high space time yield of methanol （212 g/（Lcat·h）;T=513 K,p=3MPa,SV=12000 h-1）.展开更多
A number of nanostructured carbon materials were proposed as new effective promoters for preparing modified Cu/ZnO/Al 2O 3 catalyst system for efficient hydrogen production from methanol steam reforming. Compared to t...A number of nanostructured carbon materials were proposed as new effective promoters for preparing modified Cu/ZnO/Al 2O 3 catalyst system for efficient hydrogen production from methanol steam reforming. Compared to the catalysts modified by other type of carbon materials, the ACF-promoted catalyst prepared via carbonate-coprecipitation method exhibit the highest performance in the low-temperature steam reforming of methanol. It was suggested that the intrinsic high surface area nature of ACF material may favor the generation of modified catalysts with a high surface area and improved component dispersion, thus leading to improved performance for methanol steam reforming.展开更多
The synthesis of methanol and dimethyl ether(DME) from CO hydrogenation has been investigated on Cu-based catalysts.A series of Cu/ZnO/Al2O3 catalysts were prepared using a solvent-free routine which involved a direct...The synthesis of methanol and dimethyl ether(DME) from CO hydrogenation has been investigated on Cu-based catalysts.A series of Cu/ZnO/Al2O3 catalysts were prepared using a solvent-free routine which involved a direct blend of copper/zinc/aluminum salts and citric acid,followed by calcination at 450 °C.The calcination processes were monitored using thermogravimetry differential scanning calorimetry(TG-DSC).Catalysts were further characterized using N2 adsorption,scanning electronic microscopy(SEM),X-ray diffraction(XRD),N2O oxidation followed by H2 titration,and temperature-programmed reduction with H2(H2-TPR).The reduction processes were also monitored with in-situ XRD.The physicochemical properties of catalysts depended strongly on the types of precursor salts,and catalysts prepared using Al acetate and Cu nitrate as starting materials had a larger surface area,larger exposed metallic copper surface area,and lower reduction temperature.The CO hydrogenation performances of these catalysts were compared and discussed in terms of their structures.Catalysts prepared with copper nitrate,zinc and aluminum acetates exhibited the highest catalytic activity.展开更多
以尿素为沉淀剂,采用均相沉淀法成功制备了层状Cu/Zn/Al水滑石化合物.将前驱体材料经焙烧、还原后得到Cu/ZnO/Al_2O_3催化剂,并将其用于CO_2加氢合成甲醇反应.采用X射线衍射(X-ray diffraction,XRD)、热重(thermogravimetric,TG)分析、...以尿素为沉淀剂,采用均相沉淀法成功制备了层状Cu/Zn/Al水滑石化合物.将前驱体材料经焙烧、还原后得到Cu/ZnO/Al_2O_3催化剂,并将其用于CO_2加氢合成甲醇反应.采用X射线衍射(X-ray diffraction,XRD)、热重(thermogravimetric,TG)分析、扫描电镜(scanning electron microscope,SEM)、X射线荧光(X-ray fluorescence,XRF)分析、N_2吸附、H_2程序升温还原(H_2-temperature program reduction,H_2-TPR)、氧化亚氮(N_2O)反应吸附、CO_2程序升温脱附(CO_2-temperature program desorption,CO_2-TPD)技术对所制备的样品进行表征.结果表明,相对于传统共沉淀法,以尿素作为沉淀剂,通过均相沉淀法所制备的前驱体的结晶度更高、催化剂比表面积更大、金属Cu的分散度更好.另外,采用回流处理可以获得更好的效果.活性评估结果表明,O_2转化率随金属Cu比表面积的增大而增加,而甲醇选择性则与催化剂表面碱性位的分布有关.因此,采用尿素回流处理均相沉淀法制备的Cu/ZnO/Al_2O_3催化剂的甲醇收率最高.展开更多
基金supported by the National Basic Research Program of China (No. 2011CB201404)the financial support of the State Key Laboratory for Oxo Synthesis and Selective Oxidation (OSSO) of China
文摘Methanol synthesis from hydrogenation of CO2 is investigated over Cu/ZnO/Al2O3 catalysts prepared by decomposition of M（Cu,Zn）-ammonia complexes （DMAC） at various temperatures.The catalysts were characterized in detail,including X-ray diffraction,N2 adsorption-desorption,N2O chemisorption,temperature-programmed reduction and evolved gas analyses.The influences of DMAC temperature,reaction temperature and specific Cu surface area on catalytic performance are investigated.It is considered that the aurichalcite phase in the precursor plays a key role in improving the physiochemical properties and activities of the final catalysts.The catalyst from rich-aurichalcite precursor exhibits large specific Cu surface area and high space time yield of methanol （212 g/（Lcat·h）;T=513 K,p=3MPa,SV=12000 h-1）.
文摘A number of nanostructured carbon materials were proposed as new effective promoters for preparing modified Cu/ZnO/Al 2O 3 catalyst system for efficient hydrogen production from methanol steam reforming. Compared to the catalysts modified by other type of carbon materials, the ACF-promoted catalyst prepared via carbonate-coprecipitation method exhibit the highest performance in the low-temperature steam reforming of methanol. It was suggested that the intrinsic high surface area nature of ACF material may favor the generation of modified catalysts with a high surface area and improved component dispersion, thus leading to improved performance for methanol steam reforming.
基金supported by the National Natural Science Foundation of China (Nos. 21073159 and 90610002)the National Basic Research Program (973) of China (No. 2007CB210207)the Zhejiang Provincial Natural Science Foundation of China (No. Z406142)
文摘The synthesis of methanol and dimethyl ether(DME) from CO hydrogenation has been investigated on Cu-based catalysts.A series of Cu/ZnO/Al2O3 catalysts were prepared using a solvent-free routine which involved a direct blend of copper/zinc/aluminum salts and citric acid,followed by calcination at 450 °C.The calcination processes were monitored using thermogravimetry differential scanning calorimetry(TG-DSC).Catalysts were further characterized using N2 adsorption,scanning electronic microscopy(SEM),X-ray diffraction(XRD),N2O oxidation followed by H2 titration,and temperature-programmed reduction with H2(H2-TPR).The reduction processes were also monitored with in-situ XRD.The physicochemical properties of catalysts depended strongly on the types of precursor salts,and catalysts prepared using Al acetate and Cu nitrate as starting materials had a larger surface area,larger exposed metallic copper surface area,and lower reduction temperature.The CO hydrogenation performances of these catalysts were compared and discussed in terms of their structures.Catalysts prepared with copper nitrate,zinc and aluminum acetates exhibited the highest catalytic activity.
文摘以尿素为沉淀剂,采用均相沉淀法成功制备了层状Cu/Zn/Al水滑石化合物.将前驱体材料经焙烧、还原后得到Cu/ZnO/Al_2O_3催化剂,并将其用于CO_2加氢合成甲醇反应.采用X射线衍射(X-ray diffraction,XRD)、热重(thermogravimetric,TG)分析、扫描电镜(scanning electron microscope,SEM)、X射线荧光(X-ray fluorescence,XRF)分析、N_2吸附、H_2程序升温还原(H_2-temperature program reduction,H_2-TPR)、氧化亚氮(N_2O)反应吸附、CO_2程序升温脱附(CO_2-temperature program desorption,CO_2-TPD)技术对所制备的样品进行表征.结果表明,相对于传统共沉淀法,以尿素作为沉淀剂,通过均相沉淀法所制备的前驱体的结晶度更高、催化剂比表面积更大、金属Cu的分散度更好.另外,采用回流处理可以获得更好的效果.活性评估结果表明,O_2转化率随金属Cu比表面积的增大而增加,而甲醇选择性则与催化剂表面碱性位的分布有关.因此,采用尿素回流处理均相沉淀法制备的Cu/ZnO/Al_2O_3催化剂的甲醇收率最高.
