以硝酸镍为镍源、酸/碱性硅溶胶为硅源,采用共沉淀法制备了2种Ni/SiO_(2)催化剂。采用固定床反应器,评价Ni/SiO_(2)催化剂对于2-甲基呋喃(2-MF)气相加氢合成2-甲基四氢呋喃(2-MTHF)的反应性能。通过XRD、N_(2)等温吸附-脱附、H_(2)-TPR...以硝酸镍为镍源、酸/碱性硅溶胶为硅源,采用共沉淀法制备了2种Ni/SiO_(2)催化剂。采用固定床反应器,评价Ni/SiO_(2)催化剂对于2-甲基呋喃(2-MF)气相加氢合成2-甲基四氢呋喃(2-MTHF)的反应性能。通过XRD、N_(2)等温吸附-脱附、H_(2)-TPR、NH3-TPD、XPS、FTIR和TEM对催化剂进行了表征。考察了硅溶胶的酸碱性对Ni/SiO_(2)催化剂结构及性能的影响。结果表明,以酸性硅溶胶为硅源制备的Ni/SiO_(2)催化剂以弱酸中心酸量为主且存在中强酸中心,比表面积、平均孔径大,因而该催化剂加氢活性和2-MTHF的选择性较高。Ni/SiO_(2)催化剂稳定性良好,在最优反应条件〔温度90℃、H_(2)压力2 MPa、质量空速4.4 g 2-MF/(g催化剂·h)、H_(2)与2-MF物质的量之比为4∶1〕下进行催化剂稳定性测试(200 h),2-MF的转化率达到99.8%,2-MTHF的选择性均保持在97.5%左右。展开更多
To improve the cracking behavior of hydrocarbon,Ni-Mo/SiO_(2) bimetallic catalysts were synthesized by different preparation methods(sol-gel,co-impregnation and single-impregnation) and added the additives(citric acid...To improve the cracking behavior of hydrocarbon,Ni-Mo/SiO_(2) bimetallic catalysts were synthesized by different preparation methods(sol-gel,co-impregnation and single-impregnation) and added the additives(citric acid,polyethylene glycol and cetyltrimethylammonium bromide) based on the most suitable method above.The cracking reaction of methylcyclohexane under supercritical conditions was performed as the probe reaction to estimate the catalytic performance,and the properties of Ni-Mo/SiO_(2) catalyst were characterized by N_(2) absorption-desorption,XRD,XPS,H_(2)-TPR,NH_(3)-TPD,in-situ IR of NH_(3) desorption,HRTEM and STEM-mapping so as to study the structure-activity relationship.The catalyst synthesized via sol-gel method showed the best conversion and heat sink,being 81.8% and 3.81 MJ/kg,which was closely related to strong mutual effect between active components and SiO_(2) as well as strong acid sites.Besides,the introduction of additives by sol-gel method has an affirmative influence on properties of Ni-Mo/SiO_(2) catalysts,being that the acidity(more L and B acid sites) was modulated and organic groups interact with metal to suppress the aggregation of metal species(Ni and Mo),thereby enhancing the catalytic activity.At 750℃,the conversion(89.3%) as well as heat sink(3.99 MJ/kg) of MCH cracking obtained an optimum over Ni-Mo/SiO_(2) catalyst with addition of citric acid.展开更多
文摘以硝酸镍为镍源、酸/碱性硅溶胶为硅源,采用共沉淀法制备了2种Ni/SiO_(2)催化剂。采用固定床反应器,评价Ni/SiO_(2)催化剂对于2-甲基呋喃(2-MF)气相加氢合成2-甲基四氢呋喃(2-MTHF)的反应性能。通过XRD、N_(2)等温吸附-脱附、H_(2)-TPR、NH3-TPD、XPS、FTIR和TEM对催化剂进行了表征。考察了硅溶胶的酸碱性对Ni/SiO_(2)催化剂结构及性能的影响。结果表明,以酸性硅溶胶为硅源制备的Ni/SiO_(2)催化剂以弱酸中心酸量为主且存在中强酸中心,比表面积、平均孔径大,因而该催化剂加氢活性和2-MTHF的选择性较高。Ni/SiO_(2)催化剂稳定性良好,在最优反应条件〔温度90℃、H_(2)压力2 MPa、质量空速4.4 g 2-MF/(g催化剂·h)、H_(2)与2-MF物质的量之比为4∶1〕下进行催化剂稳定性测试(200 h),2-MF的转化率达到99.8%,2-MTHF的选择性均保持在97.5%左右。
基金supported by National Natural Science Foundation of China [grant number 91841301]Fundamental Research Funds for the Central Universities [grant number YJ201791]。
文摘To improve the cracking behavior of hydrocarbon,Ni-Mo/SiO_(2) bimetallic catalysts were synthesized by different preparation methods(sol-gel,co-impregnation and single-impregnation) and added the additives(citric acid,polyethylene glycol and cetyltrimethylammonium bromide) based on the most suitable method above.The cracking reaction of methylcyclohexane under supercritical conditions was performed as the probe reaction to estimate the catalytic performance,and the properties of Ni-Mo/SiO_(2) catalyst were characterized by N_(2) absorption-desorption,XRD,XPS,H_(2)-TPR,NH_(3)-TPD,in-situ IR of NH_(3) desorption,HRTEM and STEM-mapping so as to study the structure-activity relationship.The catalyst synthesized via sol-gel method showed the best conversion and heat sink,being 81.8% and 3.81 MJ/kg,which was closely related to strong mutual effect between active components and SiO_(2) as well as strong acid sites.Besides,the introduction of additives by sol-gel method has an affirmative influence on properties of Ni-Mo/SiO_(2) catalysts,being that the acidity(more L and B acid sites) was modulated and organic groups interact with metal to suppress the aggregation of metal species(Ni and Mo),thereby enhancing the catalytic activity.At 750℃,the conversion(89.3%) as well as heat sink(3.99 MJ/kg) of MCH cracking obtained an optimum over Ni-Mo/SiO_(2) catalyst with addition of citric acid.
