Dispersion of MoO3 on low specific surface area support α-Al2O3 was studied withBET, SEM, XPS, XRD and LRS. The dispersion capacity of MoO3 on α-Al2O3 obtained by XPSand XRD are 0.15gMoO3/100m2 α-Al2O3 surface for ...Dispersion of MoO3 on low specific surface area support α-Al2O3 was studied withBET, SEM, XPS, XRD and LRS. The dispersion capacity of MoO3 on α-Al2O3 obtained by XPSand XRD are 0.15gMoO3/100m2 α-Al2O3 surface for α-Al2O3 obtained by calcinating γ-Al2O3 at1300℃ and 1200℃ and 0. 17gMoO3/100m2 α-Al2O3 for γ-Al2O3 obtained by calcinating γ-Al2O3at展开更多
Dispersion of MoO3, NiO, ZnO on rutile TiO2 with low specific surface area wasstudied with Mercury Porosimeter, SEM, XPS and Ammonia Extraction method. The dispersionthresholds of MoO3, NiO, ZnO on three rutile TiO2 c...Dispersion of MoO3, NiO, ZnO on rutile TiO2 with low specific surface area wasstudied with Mercury Porosimeter, SEM, XPS and Ammonia Extraction method. The dispersionthresholds of MoO3, NiO, ZnO on three rutile TiO2 carriers were obtained with XPS, and com-pared with those on anatase TiO2 with high specific surf are area. Ammonia Extraction methodwas used to identify the surface oxide species interarting with support surface in different strengthand it was found that the proportions of oxides that can not be extrarted by ammonia extractionare different for MoO3, NiO and ZnO which are supported on rutile TiO2.展开更多
Silicoaluminophosphate-34(SAPO-34) molecular sieves have important applications in the petrochemical industry as a result of their shape selectivity and suitable acidity. In this work, nanoaggregate SAPO-34 with a lar...Silicoaluminophosphate-34(SAPO-34) molecular sieves have important applications in the petrochemical industry as a result of their shape selectivity and suitable acidity. In this work, nanoaggregate SAPO-34 with a large external surface area was obtained by dissolving pseudoboehmite and tetraethylorthosilicate in an aqueous solution of tetraethylammonium hydroxide and subsequently adding phosphoric acid. After hydrolysis in an alkaline solution, the aluminum and silicon precursors exist as Al(OH)4-and SiO2(OH)-, respectively;this is beneficial for rapid nucleation and the formation of nanoaggregates in the following crystallization process. Additionally, to study the effect of the external surface area and pore size on the catalytic performance of different SAPO-34 structures, the alcoholysis of furfuryl alcohol to ethyl levulinate(EL) was chosen as a model reaction. In a comparison with the traditional cube-like SAPO-34, nanoaggregate SAPO-34 generated a higher yield of 74.1% of EL, whereas that with cube-like SAPO-34 was only 19.9%. Moreover, the stability was remarkably enhanced for nanoaggregate SAPO-34. The greater external surface area and larger number of external surface acid sites are helpful in improving the catalytic performance and avoiding coke deposition.展开更多
文摘Dispersion of MoO3 on low specific surface area support α-Al2O3 was studied withBET, SEM, XPS, XRD and LRS. The dispersion capacity of MoO3 on α-Al2O3 obtained by XPSand XRD are 0.15gMoO3/100m2 α-Al2O3 surface for α-Al2O3 obtained by calcinating γ-Al2O3 at1300℃ and 1200℃ and 0. 17gMoO3/100m2 α-Al2O3 for γ-Al2O3 obtained by calcinating γ-Al2O3at
文摘Dispersion of MoO3, NiO, ZnO on rutile TiO2 with low specific surface area wasstudied with Mercury Porosimeter, SEM, XPS and Ammonia Extraction method. The dispersionthresholds of MoO3, NiO, ZnO on three rutile TiO2 carriers were obtained with XPS, and com-pared with those on anatase TiO2 with high specific surf are area. Ammonia Extraction methodwas used to identify the surface oxide species interarting with support surface in different strengthand it was found that the proportions of oxides that can not be extrarted by ammonia extractionare different for MoO3, NiO and ZnO which are supported on rutile TiO2.
文摘Silicoaluminophosphate-34(SAPO-34) molecular sieves have important applications in the petrochemical industry as a result of their shape selectivity and suitable acidity. In this work, nanoaggregate SAPO-34 with a large external surface area was obtained by dissolving pseudoboehmite and tetraethylorthosilicate in an aqueous solution of tetraethylammonium hydroxide and subsequently adding phosphoric acid. After hydrolysis in an alkaline solution, the aluminum and silicon precursors exist as Al(OH)4-and SiO2(OH)-, respectively;this is beneficial for rapid nucleation and the formation of nanoaggregates in the following crystallization process. Additionally, to study the effect of the external surface area and pore size on the catalytic performance of different SAPO-34 structures, the alcoholysis of furfuryl alcohol to ethyl levulinate(EL) was chosen as a model reaction. In a comparison with the traditional cube-like SAPO-34, nanoaggregate SAPO-34 generated a higher yield of 74.1% of EL, whereas that with cube-like SAPO-34 was only 19.9%. Moreover, the stability was remarkably enhanced for nanoaggregate SAPO-34. The greater external surface area and larger number of external surface acid sites are helpful in improving the catalytic performance and avoiding coke deposition.
