A novel method for increasing the conversion and optimizing the product distribution over the catalyst of zeolite Y modified by MFI aluminosilicate precursors in the reaction of benzene alkylation with isopropanol is ...A novel method for increasing the conversion and optimizing the product distribution over the catalyst of zeolite Y modified by MFI aluminosilicate precursors in the reaction of benzene alkylation with isopropanol is reported. The catalyst(PASP MFI/Y) is prepared from the impregnation of zeolite Y with preformed MFI aluminosilicate nanoclusters. The characterization of temperature-programmed desorption of ammonia shows that the PASP MFI/Y exhibits a stronger acidity than Y zeolite does. The catalytic results show that the PASP MFI/Y exhibits a more excellent activity(conversion for isopropanol and toluene) and shape selectivity(p- and m-cymene) in the reaction than zeolite Y.展开更多
In this study,we fabricated a NiOx film by electrodeposition of an ethanediamine nickel complex precursor(pH=11)on a fluorine‐doped tin oxide substrate.The resulting film is robust and exhibits high catalytic activit...In this study,we fabricated a NiOx film by electrodeposition of an ethanediamine nickel complex precursor(pH=11)on a fluorine‐doped tin oxide substrate.The resulting film is robust and exhibits high catalytic activity for electrochemical water oxidation.Water oxidation is initiated with an overpotential of375mV(1mA/cm2)and a steady current density of8.5mA/cm2is maintained for at least10h at1.3V versus the normal hydrogen electrode.Kinetic analysis reveals that there is a2e?/3H+pre‐equilibrium process before the chemical rate‐determining step.The low‐cost preparation,robustness,and longevity make this catalyst competitive for applications in solar energy conversion and storage.展开更多
Single source molecular precursors （SSPs） provide an opportunity to get control over the microstructure of nanomaterials at atomic level. A SSP was designed and developed for the synthesis of ZnO/TiO2 nanocomposite ...Single source molecular precursors （SSPs） provide an opportunity to get control over the microstructure of nanomaterials at atomic level. A SSP was designed and developed for the synthesis of ZnO/TiO2 nanocomposite by sol gel method. In a typical synthe-sis process, a bimetallic molecular compound with chemical formula [Cl2TiZn（dmae）4] （dmae=dimethylaminoethanol） was synthesized and its chemical composition was deter-mined by elemental analysis. The obtained compound has shown excellent solubility in common organic solvents, a prerequisite for its use in sol gel method as SSP. The SSP ob-tained was controllably hydrolyzed by adding equimolar amount of water using ethanol as solvent to get ZnO/TiO2 nanocomposite gel. The resulting gel was precipitated at pH=9 and sintered at 200 ℃ （T200）, 400℃ （T400）, and 600℃ （T600）. The XRD analyses have shown that the as synthesized （non-sintered, T00） powder was amorphous. However, the crystallinity improved upon sintering, and the XRD analyses revealed that the resulting nanomaterials were composed of mixed oxides i.e., ZnO and TiO2. The ZnO was in wurtzite （hexagonal） while the TiO2 was in brookite （orthorhombic） phase. The increase in particlesize was further confirmed from BET analysis and SEM micrographs. The IR spectra ob-tained for the resulting powder have shown the peculiar vibrational bands for Zn-O and Ti-O. Furthermore, the IR spectra revealed that the non-sintered ZnO/TiO2 nanocomposite had significant number of OH group which was removed upon sintering. The photocatalytic activities of the ZnO/TiO2 nanocomposites were tested. All the samples have shown good photocatalytic activities. However, the T400 has shown higher activity than the T00, T200, and T600. The higher photocatalytic activity of T400 than T00, T200, and T600 may be due to improved crystallinity which ensures efficient grain boundary interfaces.展开更多
The MoS_2 catalysts were prepared from various molybdate precursors including inorganic and organic molybdate compounds. The sulfidation degree and morphology of active phases of MoS_2 activated by various molybdate p...The MoS_2 catalysts were prepared from various molybdate precursors including inorganic and organic molybdate compounds. The sulfidation degree and morphology of active phases of MoS_2 activated by various molybdate precursors in H_2S/H_2 stream at different temperatures were studied by X-ray photoelectron spectroscopy(XPS) and high-resolution transmission electron microscopy(HRTEM). The organic molybdate precursors lead to MoS_2 catalysts with higher sulfidation degree and smaller active phases to demonstrate higher catalytic activity during hydrodesulfurizaiton(HDS) of 4,6-DMDBT.展开更多
文摘A novel method for increasing the conversion and optimizing the product distribution over the catalyst of zeolite Y modified by MFI aluminosilicate precursors in the reaction of benzene alkylation with isopropanol is reported. The catalyst(PASP MFI/Y) is prepared from the impregnation of zeolite Y with preformed MFI aluminosilicate nanoclusters. The characterization of temperature-programmed desorption of ammonia shows that the PASP MFI/Y exhibits a stronger acidity than Y zeolite does. The catalytic results show that the PASP MFI/Y exhibits a more excellent activity(conversion for isopropanol and toluene) and shape selectivity(p- and m-cymene) in the reaction than zeolite Y.
基金supported by the National Basic Research Program of China(973 program,2014CB239402)the National Natural Science Foundation of China(21476043)the Swedish Energy Agency and K&A Wallenberg Foundation~~
文摘In this study,we fabricated a NiOx film by electrodeposition of an ethanediamine nickel complex precursor(pH=11)on a fluorine‐doped tin oxide substrate.The resulting film is robust and exhibits high catalytic activity for electrochemical water oxidation.Water oxidation is initiated with an overpotential of375mV(1mA/cm2)and a steady current density of8.5mA/cm2is maintained for at least10h at1.3V versus the normal hydrogen electrode.Kinetic analysis reveals that there is a2e?/3H+pre‐equilibrium process before the chemical rate‐determining step.The low‐cost preparation,robustness,and longevity make this catalyst competitive for applications in solar energy conversion and storage.
文摘Single source molecular precursors （SSPs） provide an opportunity to get control over the microstructure of nanomaterials at atomic level. A SSP was designed and developed for the synthesis of ZnO/TiO2 nanocomposite by sol gel method. In a typical synthe-sis process, a bimetallic molecular compound with chemical formula [Cl2TiZn（dmae）4] （dmae=dimethylaminoethanol） was synthesized and its chemical composition was deter-mined by elemental analysis. The obtained compound has shown excellent solubility in common organic solvents, a prerequisite for its use in sol gel method as SSP. The SSP ob-tained was controllably hydrolyzed by adding equimolar amount of water using ethanol as solvent to get ZnO/TiO2 nanocomposite gel. The resulting gel was precipitated at pH=9 and sintered at 200 ℃ （T200）, 400℃ （T400）, and 600℃ （T600）. The XRD analyses have shown that the as synthesized （non-sintered, T00） powder was amorphous. However, the crystallinity improved upon sintering, and the XRD analyses revealed that the resulting nanomaterials were composed of mixed oxides i.e., ZnO and TiO2. The ZnO was in wurtzite （hexagonal） while the TiO2 was in brookite （orthorhombic） phase. The increase in particlesize was further confirmed from BET analysis and SEM micrographs. The IR spectra ob-tained for the resulting powder have shown the peculiar vibrational bands for Zn-O and Ti-O. Furthermore, the IR spectra revealed that the non-sintered ZnO/TiO2 nanocomposite had significant number of OH group which was removed upon sintering. The photocatalytic activities of the ZnO/TiO2 nanocomposites were tested. All the samples have shown good photocatalytic activities. However, the T400 has shown higher activity than the T00, T200, and T600. The higher photocatalytic activity of T400 than T00, T200, and T600 may be due to improved crystallinity which ensures efficient grain boundary interfaces.
基金the financial support by the National Key Basic Research Development Program "973" Project (2012CB224800) of China
文摘The MoS_2 catalysts were prepared from various molybdate precursors including inorganic and organic molybdate compounds. The sulfidation degree and morphology of active phases of MoS_2 activated by various molybdate precursors in H_2S/H_2 stream at different temperatures were studied by X-ray photoelectron spectroscopy(XPS) and high-resolution transmission electron microscopy(HRTEM). The organic molybdate precursors lead to MoS_2 catalysts with higher sulfidation degree and smaller active phases to demonstrate higher catalytic activity during hydrodesulfurizaiton(HDS) of 4,6-DMDBT.
