The oxidative dehydrogenation（ODH） of propane on monomeric VO3 supported by CeO2（111）（VO3/CeO 2（111）） is studied by periodic density functional theory calculations. Detailed energetic, structural, and electron...The oxidative dehydrogenation（ODH） of propane on monomeric VO3 supported by CeO2（111）（VO3/CeO 2（111）） is studied by periodic density functional theory calculations. Detailed energetic, structural, and electronic properties of these reactions are determined. The calculated activation energies of the breaking of the first and second C–H bonds of propane on the VO3/CeO2（111） catalyst are compared, and it is found that both the unique structural and electronic effects of the VO3/CeO2（111） catalyst contribute to the relatively easy rupture of the first C–H bond of the propane molecule during the ODH reaction. In particular, the so-called new empty localized states that are mainly constituted of O2 porbitals of the ceria-supported VO3 species are determined to be crucial for assisting the cleavage of the first C–H bond of the propane molecule. Following this they become occupied and the remaining C–H bonds become increasingly difficult to break owing to the increasing repulsion between the localized 4 felectrons at the Cecations, resulting in the adsorption of more H and other moieties. This work illustrates that CeO2-supported monomeric vanadium oxides can exhibit unique activity and selectivity for the catalytic ODH of alkanes to alkenes.展开更多
A heterogeneous titanate nanotube （TNT） catalyst containing TiO2, Na, and V has been synthesized and used in the chemoselective oxidation of sulfides to the corresponding sulfoxides in the presence of 30%H2O2 in wat...A heterogeneous titanate nanotube （TNT） catalyst containing TiO2, Na, and V has been synthesized and used in the chemoselective oxidation of sulfides to the corresponding sulfoxides in the presence of 30%H2O2 in water. Some of the advantages of our method include excellent yields, heterogene‐ous conditions, simplicity, compatibility with a variety of functionalities, and ease of isolation of the products. Fourier transform infrared spectroscopy, X‐ray diffraction, scanning electron microscopy, transmission electron microscopy, and N2 adsorption were used for structural and textural charac‐terization of the catalyst （VNaTNT）.展开更多
In this work, BiV04 powders were synthesized by a sol-gel method, and the BiV04 gels with different calcination temperature were investigated by X-ray diffraction （XRD）. Absorption range and band gap energy, which a...In this work, BiV04 powders were synthesized by a sol-gel method, and the BiV04 gels with different calcination temperature were investigated by X-ray diffraction （XRD）. Absorption range and band gap energy, which are respon- sible for the observed photocatalyst behavior, were investigated by UV/vis diffuse reflectance spectroscopy （DRS） for pure and silver oxide loaded BiV04. Pbotocatalytic properties of the prepared samples were examined by studying the degradation of the methyl orange. When using NaCI02 as an electron acceptor, the possible photocatalytic mech- anism has been discussed by photocatalytic reactions. With the help of electron acceptor, the results show clearly that the BiV04 loaded silver oxide exhibited superior photocatalytic activity in simulated dye wastewater treatment.展开更多
In order to evaluate the role of vanadium in the hydrogenation (HYD) reaction, a series of alumina supported vanadium catalysts were prepared and characterized by SEM, XRD, Raman spectrometry, 51V NMR, XPS, as well as...In order to evaluate the role of vanadium in the hydrogenation (HYD) reaction, a series of alumina supported vanadium catalysts were prepared and characterized by SEM, XRD, Raman spectrometry, 51V NMR, XPS, as well as TPR analyses. The catalytic performance of vanadium in HYD of model molecules (naphthalene) and real feedstock (Kuwait atmospheric residue) was studied after sulfidation of the catalysts. It can be concluded that the HYD capabilities of V/Al2O3 catalysts are lower than that of conventional NiMo/Al2O3 catalyst (RefNiMo). The V/Al2O3 catalysts can only facilitate hydrogenation of the first ring of naphthalene, but have little effect on the further hydrogenation of tetralin. Owing to the different forms of metals and sulfur compounds in residue, the weak HYD activity of V/Al2O3 catalysts is able to facilitate the HDM reaction of the residue, albeit with a slight effect on HDS activity.展开更多
基金supported by the National Natural Science Foundation of China(21421004,21573067,91545103)Program of Shanghai Academic Research Leader(17XD1401400)~~
文摘The oxidative dehydrogenation（ODH） of propane on monomeric VO3 supported by CeO2（111）（VO3/CeO 2（111）） is studied by periodic density functional theory calculations. Detailed energetic, structural, and electronic properties of these reactions are determined. The calculated activation energies of the breaking of the first and second C–H bonds of propane on the VO3/CeO2（111） catalyst are compared, and it is found that both the unique structural and electronic effects of the VO3/CeO2（111） catalyst contribute to the relatively easy rupture of the first C–H bond of the propane molecule during the ODH reaction. In particular, the so-called new empty localized states that are mainly constituted of O2 porbitals of the ceria-supported VO3 species are determined to be crucial for assisting the cleavage of the first C–H bond of the propane molecule. Following this they become occupied and the remaining C–H bonds become increasingly difficult to break owing to the increasing repulsion between the localized 4 felectrons at the Cecations, resulting in the adsorption of more H and other moieties. This work illustrates that CeO2-supported monomeric vanadium oxides can exhibit unique activity and selectivity for the catalytic ODH of alkanes to alkenes.
基金Shahreza Branch, Islamic Azad University for financial support
文摘A heterogeneous titanate nanotube （TNT） catalyst containing TiO2, Na, and V has been synthesized and used in the chemoselective oxidation of sulfides to the corresponding sulfoxides in the presence of 30%H2O2 in water. Some of the advantages of our method include excellent yields, heterogene‐ous conditions, simplicity, compatibility with a variety of functionalities, and ease of isolation of the products. Fourier transform infrared spectroscopy, X‐ray diffraction, scanning electron microscopy, transmission electron microscopy, and N2 adsorption were used for structural and textural charac‐terization of the catalyst （VNaTNT）.
基金Supported by the Education Department of Heilongjiang Province(12541111)the Program for Innovative Research Team in University of Heilongjiang Province(2013TD008)the Key Laboratory of Green Chemical Engineering and Technology of College of Heilongjiang Province and Harbin University of Science and Technology and the Technology and Innovative Experimental Project of Harbin University of Science and Technology
文摘In this work, BiV04 powders were synthesized by a sol-gel method, and the BiV04 gels with different calcination temperature were investigated by X-ray diffraction （XRD）. Absorption range and band gap energy, which are respon- sible for the observed photocatalyst behavior, were investigated by UV/vis diffuse reflectance spectroscopy （DRS） for pure and silver oxide loaded BiV04. Pbotocatalytic properties of the prepared samples were examined by studying the degradation of the methyl orange. When using NaCI02 as an electron acceptor, the possible photocatalytic mech- anism has been discussed by photocatalytic reactions. With the help of electron acceptor, the results show clearly that the BiV04 loaded silver oxide exhibited superior photocatalytic activity in simulated dye wastewater treatment.
基金supported by the National Basic Research Program of China(973 Program No.2012CB224802)
文摘In order to evaluate the role of vanadium in the hydrogenation (HYD) reaction, a series of alumina supported vanadium catalysts were prepared and characterized by SEM, XRD, Raman spectrometry, 51V NMR, XPS, as well as TPR analyses. The catalytic performance of vanadium in HYD of model molecules (naphthalene) and real feedstock (Kuwait atmospheric residue) was studied after sulfidation of the catalysts. It can be concluded that the HYD capabilities of V/Al2O3 catalysts are lower than that of conventional NiMo/Al2O3 catalyst (RefNiMo). The V/Al2O3 catalysts can only facilitate hydrogenation of the first ring of naphthalene, but have little effect on the further hydrogenation of tetralin. Owing to the different forms of metals and sulfur compounds in residue, the weak HYD activity of V/Al2O3 catalysts is able to facilitate the HDM reaction of the residue, albeit with a slight effect on HDS activity.
