Compared to reforming reactions using hydrocarbons,ethanol steam reforming(ESR)is a sustainable alternative for hydrogen(H_(2))production since ethanol can be produced sustainably using biomass.This work explores the ...Compared to reforming reactions using hydrocarbons,ethanol steam reforming(ESR)is a sustainable alternative for hydrogen(H_(2))production since ethanol can be produced sustainably using biomass.This work explores the catalyst design strategies for preparing the Ni supported on ZSM-5 zeolite catalysts to promote ESR.Specifically,two-dimensional ZSM-5 nanosheet and conventional ZSM-5 crystal were used as the catalyst carriers and two synthesis strategies,i.e.,in situ encapsulation and wet impregnation method,were employed to prepare the catalysts.Based on the comparative characterization of the catalysts and comparative catalytic assessments,it was found that the combination of the in situ encapsulation synthesis and the ZSM-5 nanosheet carrier was the effective strategy to develop catalysts for promoting H_(2) production via ESR due to the improved mass transfer(through the 2-D structure of ZSM-5 nanosheet)and formation of confined small Ni nanoparticles(resulted via the in situ encapsulation synthesis).In addition,the resulting ZSM-5 nanosheet supported Ni catalyst also showed high Ni dispersion and high accessibility to Ni sites by the reactants,being able to improve the activity and stability of catalysts and suppress metal sintering and coking during ESR at high reaction temperatures.Thus,the Ni supported on ZSM-5 nanosheet catalyst prepared by encapsulation showed the stable performance with~88% ethanol conversion and~65% H_(2) yield achieved during a 48-h longevity test at 550-C.展开更多
Nanosized Ga-containing ZSM-5 zeolites were prepared via isomorphous substitution and impregnation followed by characterized using various techniques. The catalytic performance of the zeolites for the aromatization of...Nanosized Ga-containing ZSM-5 zeolites were prepared via isomorphous substitution and impregnation followed by characterized using various techniques. The catalytic performance of the zeolites for the aromatization of 1-hexene was investigated. The results indicate that isomorphous substitution promotes the incorporation of Ga heteroatoms into the framework along with the formation of extra-framework GaO;species（[GaO;]a） that have stronger interactions with the negative potential of the framework. In addition, based on the Py-IR results and catalytic performance, the [GaO;]aspecies with stronger Lewis acid sites produced a better synergism with moderate Br?nsted acid sites and thus improved the selectivity to aromatic compounds. However, the impregnation results in the formation of Ga;O;phase and small amounts of GaO;species that are mainly located on the external surface（[GaO;];）, which contribute to weaker Lewis acid sites due to weaker interactions with the zeolite framework. During 1-hexene aromatization, the nanosized Ga isomorphously substituted ZSM-5 zeolite samples（Gax-NZ5） exhibited better catalytic performance compared to the impregnated samples, and the highest aromatic yield（i.e.,65.4 wt%） was achieved over the Ga4.2-NZ5 sample, which contained with the highest Ga content.展开更多
调整双季铵盐表面活性剂与单季铵盐表面活性剂的使用量,通过协同晶化的方式合成了高结晶度、高介孔容的薄层ZSM-5沸石。利用XRD、XRF、SEM、TEM、NH3-TPD、低温氮气物理吸脱附以及27Al MAS NMR对沸石样品进行表征,并评价其甲醇制丙烯反...调整双季铵盐表面活性剂与单季铵盐表面活性剂的使用量,通过协同晶化的方式合成了高结晶度、高介孔容的薄层ZSM-5沸石。利用XRD、XRF、SEM、TEM、NH3-TPD、低温氮气物理吸脱附以及27Al MAS NMR对沸石样品进行表征,并评价其甲醇制丙烯反应(MTP)催化性能。结果表明,薄层沸石的b轴厚度随着双季铵盐表面活性剂使用量的减少而增加,适量的单季铵盐表面活性剂的加入可以起到协同晶化的作用,能够有效稳定胶束,从而调控沸石的形貌。优化2种季铵盐表面活性剂的使用量所得薄层ZSM-5沸石的比表面积和介孔孔容都有所增加,在甲醇制丙烯反应中的活性稳定性也得到较大改善。此外,协同晶化的方式减少了双季铵盐表面活性剂的使用,有利于降低薄层ZSM-5沸石的合成成本。展开更多
基金funding from the European Union's Horizon 2020 Research and Innovation Program(872102)P.S.thanks the Science Achievement Scholarship of Thailand(SAST)for her research secondment at The University of Manchester.Y.J.thanks the National Natural Science Foundation of China(22378407)for funding.
文摘Compared to reforming reactions using hydrocarbons,ethanol steam reforming(ESR)is a sustainable alternative for hydrogen(H_(2))production since ethanol can be produced sustainably using biomass.This work explores the catalyst design strategies for preparing the Ni supported on ZSM-5 zeolite catalysts to promote ESR.Specifically,two-dimensional ZSM-5 nanosheet and conventional ZSM-5 crystal were used as the catalyst carriers and two synthesis strategies,i.e.,in situ encapsulation and wet impregnation method,were employed to prepare the catalysts.Based on the comparative characterization of the catalysts and comparative catalytic assessments,it was found that the combination of the in situ encapsulation synthesis and the ZSM-5 nanosheet carrier was the effective strategy to develop catalysts for promoting H_(2) production via ESR due to the improved mass transfer(through the 2-D structure of ZSM-5 nanosheet)and formation of confined small Ni nanoparticles(resulted via the in situ encapsulation synthesis).In addition,the resulting ZSM-5 nanosheet supported Ni catalyst also showed high Ni dispersion and high accessibility to Ni sites by the reactants,being able to improve the activity and stability of catalysts and suppress metal sintering and coking during ESR at high reaction temperatures.Thus,the Ni supported on ZSM-5 nanosheet catalyst prepared by encapsulation showed the stable performance with~88% ethanol conversion and~65% H_(2) yield achieved during a 48-h longevity test at 550-C.
基金Key Research and Development Plan of Shaanxi Province(2023-YBGY-290)Research Project of Shaanxi Yanchang Petroleum(Group)Co.,Ltd.(No.ycsy2023ky-B-81)。
基金supported by the National Natural Science Foundation of China(Nos.21276067 and 21676074)Programs of International S&T cooperation(No.2014DFR41110)
文摘Nanosized Ga-containing ZSM-5 zeolites were prepared via isomorphous substitution and impregnation followed by characterized using various techniques. The catalytic performance of the zeolites for the aromatization of 1-hexene was investigated. The results indicate that isomorphous substitution promotes the incorporation of Ga heteroatoms into the framework along with the formation of extra-framework GaO;species（[GaO;]a） that have stronger interactions with the negative potential of the framework. In addition, based on the Py-IR results and catalytic performance, the [GaO;]aspecies with stronger Lewis acid sites produced a better synergism with moderate Br?nsted acid sites and thus improved the selectivity to aromatic compounds. However, the impregnation results in the formation of Ga;O;phase and small amounts of GaO;species that are mainly located on the external surface（[GaO;];）, which contribute to weaker Lewis acid sites due to weaker interactions with the zeolite framework. During 1-hexene aromatization, the nanosized Ga isomorphously substituted ZSM-5 zeolite samples（Gax-NZ5） exhibited better catalytic performance compared to the impregnated samples, and the highest aromatic yield（i.e.,65.4 wt%） was achieved over the Ga4.2-NZ5 sample, which contained with the highest Ga content.
文摘调整双季铵盐表面活性剂与单季铵盐表面活性剂的使用量,通过协同晶化的方式合成了高结晶度、高介孔容的薄层ZSM-5沸石。利用XRD、XRF、SEM、TEM、NH3-TPD、低温氮气物理吸脱附以及27Al MAS NMR对沸石样品进行表征,并评价其甲醇制丙烯反应(MTP)催化性能。结果表明,薄层沸石的b轴厚度随着双季铵盐表面活性剂使用量的减少而增加,适量的单季铵盐表面活性剂的加入可以起到协同晶化的作用,能够有效稳定胶束,从而调控沸石的形貌。优化2种季铵盐表面活性剂的使用量所得薄层ZSM-5沸石的比表面积和介孔孔容都有所增加,在甲醇制丙烯反应中的活性稳定性也得到较大改善。此外,协同晶化的方式减少了双季铵盐表面活性剂的使用,有利于降低薄层ZSM-5沸石的合成成本。
