Pr0.7Zr0.3O2-δ solid solution was prepared by co-precipitation method and used as an oxygen carrier in the selective oxidation of methane to syngas(methane/air redox process). The evolution on the physicochemical pro...Pr0.7Zr0.3O2-δ solid solution was prepared by co-precipitation method and used as an oxygen carrier in the selective oxidation of methane to syngas(methane/air redox process). The evolution on the physicochemical properties of Pr0.7Zr0.3O2-δ during the redox process was studied by means of X-ray diffraction(XRD), H2 temperature-programmed reduction(H2-TPR), O2temperature-programmed desorption(O2-TPD), Brunauer-Emmett-Teller(BET) surface area measurement and X-ray photoelectron spectroscopy(XPS) technologies. The results indicated that Pr0.7Zr0.3O2-δ solid solution showed the high activity for the methane conversion to syngas with a high CO selectivity in the range of 83.5%-88.1%. Though Pr-Zr solid solution possessed high thermal stability, lattice oxygen was obviously reduced for the recycled sample due to decreased surface oxygen which promoted oxygen vacancies. The increased oxygen vacancies seemed to enhance the oxygen transfer ability in the redox process and provided sufficient oxygen for the methane selective oxidation, resulting in a satisfactory activity. The problem of hot pot was avoided by comparing fresh, aged and recycle sample in the reaction.展开更多
High density of phenyl rings makes PAF-1 have robust structure and highly lipophilic pore, which make it very suitable for organocatalysis. However, there is no report about using PAF-1 as platform for enantioselectiv...High density of phenyl rings makes PAF-1 have robust structure and highly lipophilic pore, which make it very suitable for organocatalysis. However, there is no report about using PAF-1 as platform for enantioselective organocatalysis.In this paper, using PAF-1 as the platform, a chiral prolinamide catalytic site was introduced onto the framework of PAF-1 via a series of stepwise post-synthetic modifications,obtaining a novel PAF-supported chiral catalyst named PAF-1-NHPro. Then its enantioselective catalytic performance was studied by subjecting it to catalyze the model Aldol reaction between p-nitrobenzaldehyde and cyclohexanone.PAF-1-NHPro showed good diastereoselectivity and enantioselectivity with excellent and easy recyclability.展开更多
The present study reports a highly selective and stable catalytic approach for producing tetralin, an important chemical, solvent, and H2 storage material. Transition metal phosphides （MOP, Ni2P, Co2P, and Fe2P） wer...The present study reports a highly selective and stable catalytic approach for producing tetralin, an important chemical, solvent, and H2 storage material. Transition metal phosphides （MOP, Ni2P, Co2P, and Fe2P） were prepared by wet impregnation and temperature-programmed reduction and characterized by X-ray diffraction （XRD）, energy dispersive X-ray spectroscopy （EDX）, EDX mapping, scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, brunauer-emmett- teller （BET）, temperature-programmed desorption of ammonia （NH3-TPD）, and fourier transform infrared spectroscopy of pyridine （pyridine-FTIR）. Of all the transition metal phosphides MoP was formed at a lower reduction temperature, which resuited in smaller particle size that enhanced the overall surface area of the catalyst. The existence of weak, moderate, and Lewis acidic sites over MoP were responsible for its high tetralin selectivity （90%） and stability during the 100 h reaction on-stream in a fixed-bed reactor.展开更多
基金Projects(51374004,51174105,51204083,51104074,51306084)supported by the National Natural Science Foundation of ChinaProjects(2012FD016,2014HB006)supported by the Applied Basic Research Program of Yunnan Province,ChinaProject(2010241)supported by the Analysis and Testing Foundation of Kunming University of Science and Technology,China
文摘Pr0.7Zr0.3O2-δ solid solution was prepared by co-precipitation method and used as an oxygen carrier in the selective oxidation of methane to syngas(methane/air redox process). The evolution on the physicochemical properties of Pr0.7Zr0.3O2-δ during the redox process was studied by means of X-ray diffraction(XRD), H2 temperature-programmed reduction(H2-TPR), O2temperature-programmed desorption(O2-TPD), Brunauer-Emmett-Teller(BET) surface area measurement and X-ray photoelectron spectroscopy(XPS) technologies. The results indicated that Pr0.7Zr0.3O2-δ solid solution showed the high activity for the methane conversion to syngas with a high CO selectivity in the range of 83.5%-88.1%. Though Pr-Zr solid solution possessed high thermal stability, lattice oxygen was obviously reduced for the recycled sample due to decreased surface oxygen which promoted oxygen vacancies. The increased oxygen vacancies seemed to enhance the oxygen transfer ability in the redox process and provided sufficient oxygen for the methane selective oxidation, resulting in a satisfactory activity. The problem of hot pot was avoided by comparing fresh, aged and recycle sample in the reaction.
基金supported by National Basic Research Program of China (2014CB931804)the National Natural Science Foundation of China (21302061 and 21531003)
文摘High density of phenyl rings makes PAF-1 have robust structure and highly lipophilic pore, which make it very suitable for organocatalysis. However, there is no report about using PAF-1 as platform for enantioselective organocatalysis.In this paper, using PAF-1 as the platform, a chiral prolinamide catalytic site was introduced onto the framework of PAF-1 via a series of stepwise post-synthetic modifications,obtaining a novel PAF-supported chiral catalyst named PAF-1-NHPro. Then its enantioselective catalytic performance was studied by subjecting it to catalyze the model Aldol reaction between p-nitrobenzaldehyde and cyclohexanone.PAF-1-NHPro showed good diastereoselectivity and enantioselectivity with excellent and easy recyclability.
基金financial support from the Special Funds of the National Natural Science Foundation of China(21127011)National High Technology Research and Development Program of China(2011AA050606)National Natural Science Foundation of China(Petrochemical Joint Fund,U1162106)
文摘The present study reports a highly selective and stable catalytic approach for producing tetralin, an important chemical, solvent, and H2 storage material. Transition metal phosphides （MOP, Ni2P, Co2P, and Fe2P） were prepared by wet impregnation and temperature-programmed reduction and characterized by X-ray diffraction （XRD）, energy dispersive X-ray spectroscopy （EDX）, EDX mapping, scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, brunauer-emmett- teller （BET）, temperature-programmed desorption of ammonia （NH3-TPD）, and fourier transform infrared spectroscopy of pyridine （pyridine-FTIR）. Of all the transition metal phosphides MoP was formed at a lower reduction temperature, which resuited in smaller particle size that enhanced the overall surface area of the catalyst. The existence of weak, moderate, and Lewis acidic sites over MoP were responsible for its high tetralin selectivity （90%） and stability during the 100 h reaction on-stream in a fixed-bed reactor.
