The surface nature of fresh Mo_2N/Al_2O_3,Mo_2C/Al_2O_3 and M0P/Al_2O_3 catalysts,which were synthesized directly in the IR cell to avoid passivation,were characterized by in situ IR spectroscopy with CO as a probe mo...The surface nature of fresh Mo_2N/Al_2O_3,Mo_2C/Al_2O_3 and M0P/Al_2O_3 catalysts,which were synthesized directly in the IR cell to avoid passivation,were characterized by in situ IR spectroscopy with CO as a probe molecule. CO adsorbed on fresh catalysts showed characteristic IR bands at 2045 cm^(-1) for Mo_2N/Al_2O_3 catalyst,2054 cm^(-1) for Mo_2C/Al_2O_3 catalyst and 2037 cm^(-1) for MoP/Al_2O_3 catalyst,respectively.A strong band at 2200 cm^(-1) for Mo_2N/Al_2O_3 catalyst,which could be ascribed to NCO species formed when CO reacted upon surface active nitrogen atoms,and a weak band at 2196 cm^(-1) for Mo_2C/Al_2O_3 catalyst,which could be attributed to CCO species,were also detected.CO adsorbed on fresh Mo_2N/Al_2O_3 catalyst,Mo_2C/Al_2O_3 catalyst and MoP/Al_2O_3 catalyst,showed strong molecular adsorption,just like noble metals.Our experimental results are bolstered by direct IR evidence demonstrating the similarity in surface electronic property between the fresh Mo_2N/Al_2O_3,Mo_2C/Al_2O_3 and MoP/Al_2O_3 catalysts and noble metals.展开更多
The adsorption of acetonitrile and its co-adsorption with CO on fresh Mo<sub>2</sub>C/Al<sub>2</sub>O<sub>3</sub> catalyst have been studied by insitu FT-IR spectroscopy.Linearly ad...The adsorption of acetonitrile and its co-adsorption with CO on fresh Mo<sub>2</sub>C/Al<sub>2</sub>O<sub>3</sub> catalyst have been studied by insitu FT-IR spectroscopy.Linearly adsorbed CH<sub>3</sub>CN and CH<sub>3</sub>CH<sub>2</sub>NH<sub>2</sub> were formed after CH<sub>3</sub>CN adsorption on the Mo<sub>2</sub>C/ Al<sub>2</sub>O<sub>3</sub> catalyst.The appearance of a strong band at 1578 cm<sup>-1</sup> indicates that CH<sub>3</sub>CN was reactive with hydrogen on the Mo<sub>2</sub>C/Al<sub>2</sub>O<sub>3</sub> catalyst.展开更多
Partial oxidation of methane to syngas （POM） over Rh/SiO2 catalyst was investigated using in-situ FT-IR. When methane interacted with 1.0wt%Rh/SiO2 catalyst, it was dissociated to adsorbed hydrogen and CHx species. ...Partial oxidation of methane to syngas （POM） over Rh/SiO2 catalyst was investigated using in-situ FT-IR. When methane interacted with 1.0wt%Rh/SiO2 catalyst, it was dissociated to adsorbed hydrogen and CHx species. The adsorbed hydrogen atoms were transferred to SiO2 surface by ＂spill-over＂ and reacted with lattice oxygen to form surface -OH species. POM mechanism was investigated over Rh/SiO2 catalyst using in-situ FT-IR. It was found that CO2 was formed before CO could be detected when CH4 and O2 were introduced over the preoxidized Rh/SiO2 catalyst, whereas CO was detected before CO2 was formed over the prereduced Rh/SiO2 catalyst.展开更多
Multiwall carbon nanotubes （MWNTs） and alumina are combined to give a new type of nanohybrid for Fisher-Tropsch synthesis （FTS） catalyst support. Alumina nano-particles （10 wt%） were introduced directly on funct...Multiwall carbon nanotubes （MWNTs） and alumina are combined to give a new type of nanohybrid for Fisher-Tropsch synthesis （FTS） catalyst support. Alumina nano-particles （10 wt%） were introduced directly on functionalized MWNTs by a modified sol-gel method. Microstructure observations show that alumina particles were homogeneously dispersed on the inside and outside of modified MWNTs surfaces. 15 wt% cobalt loading catalysts were prepared with this nanohybrid and γ-alumina as a reference, using a sol-gel technique and wet impregnation method respectively. These catalysts were characterized by TEM, XRD, N2-adsorption, H2 chemisorption and TPR. The deposition of cobalt nanoparticles synthesized by sol-gel technique on the MWNTs nanohybrid shift the reduction peaks to a low temperature, indicating higher reducibility for uniform cobalt particles. Nanohybrid also aided in high dispersion of metal clusters and high stability and performance of catalyst. The proposed MWNTs nanohybrid-supported cobalt catalysts showed the improved FTS rate （gHc/（gcat.min））, CO conversion （%）, and water gas shift rate （WGS）（gcoz/（gcat.h）） of 0.012, 52, and 30E-3, respectively, as compared to those of 0.007, 25, and 18E-3, respectively, on the γ-alumina-supported cobalt catalysts with the same Co loading.展开更多
基金supported by the National Nature Science Foundation of China(No.20903054).
文摘The surface nature of fresh Mo_2N/Al_2O_3,Mo_2C/Al_2O_3 and M0P/Al_2O_3 catalysts,which were synthesized directly in the IR cell to avoid passivation,were characterized by in situ IR spectroscopy with CO as a probe molecule. CO adsorbed on fresh catalysts showed characteristic IR bands at 2045 cm^(-1) for Mo_2N/Al_2O_3 catalyst,2054 cm^(-1) for Mo_2C/Al_2O_3 catalyst and 2037 cm^(-1) for MoP/Al_2O_3 catalyst,respectively.A strong band at 2200 cm^(-1) for Mo_2N/Al_2O_3 catalyst,which could be ascribed to NCO species formed when CO reacted upon surface active nitrogen atoms,and a weak band at 2196 cm^(-1) for Mo_2C/Al_2O_3 catalyst,which could be attributed to CCO species,were also detected.CO adsorbed on fresh Mo_2N/Al_2O_3 catalyst,Mo_2C/Al_2O_3 catalyst and MoP/Al_2O_3 catalyst,showed strong molecular adsorption,just like noble metals.Our experimental results are bolstered by direct IR evidence demonstrating the similarity in surface electronic property between the fresh Mo_2N/Al_2O_3,Mo_2C/Al_2O_3 and MoP/Al_2O_3 catalysts and noble metals.
文摘The adsorption of acetonitrile and its co-adsorption with CO on fresh Mo<sub>2</sub>C/Al<sub>2</sub>O<sub>3</sub> catalyst have been studied by insitu FT-IR spectroscopy.Linearly adsorbed CH<sub>3</sub>CN and CH<sub>3</sub>CH<sub>2</sub>NH<sub>2</sub> were formed after CH<sub>3</sub>CN adsorption on the Mo<sub>2</sub>C/ Al<sub>2</sub>O<sub>3</sub> catalyst.The appearance of a strong band at 1578 cm<sup>-1</sup> indicates that CH<sub>3</sub>CN was reactive with hydrogen on the Mo<sub>2</sub>C/Al<sub>2</sub>O<sub>3</sub> catalyst.
基金This study was supported by the grant of 2004C31053 from the Ministry of Science and Technology of Zhejiang Province, China, and the grant of Y404305 from the Natural Science Foundation of Zhejiang Province, Chinathe grant of 20673101, 20673102 from National Natural Science Foundation of China.
文摘Partial oxidation of methane to syngas （POM） over Rh/SiO2 catalyst was investigated using in-situ FT-IR. When methane interacted with 1.0wt%Rh/SiO2 catalyst, it was dissociated to adsorbed hydrogen and CHx species. The adsorbed hydrogen atoms were transferred to SiO2 surface by ＂spill-over＂ and reacted with lattice oxygen to form surface -OH species. POM mechanism was investigated over Rh/SiO2 catalyst using in-situ FT-IR. It was found that CO2 was formed before CO could be detected when CH4 and O2 were introduced over the preoxidized Rh/SiO2 catalyst, whereas CO was detected before CO2 was formed over the prereduced Rh/SiO2 catalyst.
基金supported by the Research Council of the Research Institute of Petroleum Industrythe Research and Development of the National Iranian Oil Company
文摘Multiwall carbon nanotubes （MWNTs） and alumina are combined to give a new type of nanohybrid for Fisher-Tropsch synthesis （FTS） catalyst support. Alumina nano-particles （10 wt%） were introduced directly on functionalized MWNTs by a modified sol-gel method. Microstructure observations show that alumina particles were homogeneously dispersed on the inside and outside of modified MWNTs surfaces. 15 wt% cobalt loading catalysts were prepared with this nanohybrid and γ-alumina as a reference, using a sol-gel technique and wet impregnation method respectively. These catalysts were characterized by TEM, XRD, N2-adsorption, H2 chemisorption and TPR. The deposition of cobalt nanoparticles synthesized by sol-gel technique on the MWNTs nanohybrid shift the reduction peaks to a low temperature, indicating higher reducibility for uniform cobalt particles. Nanohybrid also aided in high dispersion of metal clusters and high stability and performance of catalyst. The proposed MWNTs nanohybrid-supported cobalt catalysts showed the improved FTS rate （gHc/（gcat.min））, CO conversion （%）, and water gas shift rate （WGS）（gcoz/（gcat.h）） of 0.012, 52, and 30E-3, respectively, as compared to those of 0.007, 25, and 18E-3, respectively, on the γ-alumina-supported cobalt catalysts with the same Co loading.
基金the National Key R&D Program of China(2016YFA0202804)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB17020400)+2 种基金the Youth Innovation Promotion Association CAS for financial supportthe National Natural Science Foundation of China(21506204,21476226)Dalian Science Foundation for Distinguished Young Scholars(2016RJ04)~~
