A functionalized material, PW/SBA-15m, was prepared successfully in diluted H_2SO_4 aqueous solutions by immobilizing 12-tungstophosphates on chemically modified mesoporous silica SBA-15 and characterized by elemental...A functionalized material, PW/SBA-15m, was prepared successfully in diluted H_2SO_4 aqueous solutions by immobilizing 12-tungstophosphates on chemically modified mesoporous silica SBA-15 and characterized by elemental analysis, FTIR, ~ ~31 P MAS NMR, XRD and TEM. The results indicate that the framework of SBA-15 and the Keggin structure of PW_~12 O^3- _~40 were retained, and that 23%-33%(mass fraction) of ~PW_~12 O^3- _~40 was immobilized; the PW_~12 O^3- _~40 anions were finely dispersed on the pore wall of SBA-15. Having been leached in ethanol at 60 ℃ for 7 h, the loss of PW_~12 O^3- _~40 anions was not found.展开更多
A mesoporous MCM-48 membrane was synthesized on a coarse-pore α-alumina ceramic tube by hydrothermal treatment by using a cationic surfactant as the structure-directing agent under basic conditions. The products were...A mesoporous MCM-48 membrane was synthesized on a coarse-pore α-alumina ceramic tube by hydrothermal treatment by using a cationic surfactant as the structure-directing agent under basic conditions. The products were characterized by small-angle X-ray diffraction, SEM measurements and N_2 adsorption experiments. The X-ray diffraction(XRD) results show that the membrane possesses a periodic mesostructure, which is typical for an MCM-48 material. The results of the SEM measurements indicate that MCM-48 grew in the pores of the support and formed a continuous membrane. The N_2 adsorption and desorption isotherms also show that the membrane is a typical mesoporous material with pore channel size of about 2.74 nm.展开更多
文摘A functionalized material, PW/SBA-15m, was prepared successfully in diluted H_2SO_4 aqueous solutions by immobilizing 12-tungstophosphates on chemically modified mesoporous silica SBA-15 and characterized by elemental analysis, FTIR, ~ ~31 P MAS NMR, XRD and TEM. The results indicate that the framework of SBA-15 and the Keggin structure of PW_~12 O^3- _~40 were retained, and that 23%-33%(mass fraction) of ~PW_~12 O^3- _~40 was immobilized; the PW_~12 O^3- _~40 anions were finely dispersed on the pore wall of SBA-15. Having been leached in ethanol at 60 ℃ for 7 h, the loss of PW_~12 O^3- _~40 anions was not found.
文摘A mesoporous MCM-48 membrane was synthesized on a coarse-pore α-alumina ceramic tube by hydrothermal treatment by using a cationic surfactant as the structure-directing agent under basic conditions. The products were characterized by small-angle X-ray diffraction, SEM measurements and N_2 adsorption experiments. The X-ray diffraction(XRD) results show that the membrane possesses a periodic mesostructure, which is typical for an MCM-48 material. The results of the SEM measurements indicate that MCM-48 grew in the pores of the support and formed a continuous membrane. The N_2 adsorption and desorption isotherms also show that the membrane is a typical mesoporous material with pore channel size of about 2.74 nm.
