A series CeO2（ZrO2）/TiO2 catalysts were modified with Er using a sol-gel method.The catalytic activity of the obtained catalysts in the selective catalytic reduction（SCR） of NO with NH3 was investigated to determi...A series CeO2（ZrO2）/TiO2 catalysts were modified with Er using a sol-gel method.The catalytic activity of the obtained catalysts in the selective catalytic reduction（SCR） of NO with NH3 was investigated to determine the appropriate Er dosage.The catalysts were characterized using X-ray diffraction,N2 adsorption,NH3 temperature-programmed desorption,H2 temperature-programmed reduction,photoluminescence spectroscopy,electron paramagnetic resonance spectroscopy,and X-ray photoelectron spectroscopy.The results showed that the optimum Er/Ce molar ratio was 0.10;this catalyst had excellent resistance to catalyst poisoning caused by vapor and sulfur and gave more than 90% NO conversion at 220–395 ℃ and a gas hourly space velocity of 71 400 h^-1.Er incorporation increased the Ti^3＋ concentrations,oxygen storage capacities,and oxygen vacancy concentrations of the catalysts,resulting in excellent catalytic performance.Er incorporation also decreased the acid strength and inhibited growth of TiO2 and CeO2 crystal particles,which increased the catalytic activity.The results show that high oxygen vacancy concentrations and oxygen storage capacities,large amounts of Ti^3＋,and low acid strengths give excellent SCR activity.展开更多
Catalyst plays an important role in the dehydration of N-（hydroxylethyl）pyrrolidone （NHP） to prepare N-vinyl-pyrrolidone （NVP）. At present, NVP yield is only about 30% on commercial ZrO2 catalyst. A coupled prec...Catalyst plays an important role in the dehydration of N-（hydroxylethyl）pyrrolidone （NHP） to prepare N-vinyl-pyrrolidone （NVP）. At present, NVP yield is only about 30% on commercial ZrO2 catalyst. A coupled precipitation and solid dispersion technique was designed to prepare the nano-ZrO2 catalyst, in which rare earth metal oxides （REOx） was used as electronic promoter. The results indicated that the catalyst doped REOx （S-1.0） exhibits the optimum performance of NHP dehydration at moderate conditions. NHP conversion and NVP selectivity are respectively 97.0%, 82.3%. Of special interest is that the indexes of the catalyst （S-1.0-1.0） are up to 98.4% and 89.2% respectively. Furthermore, this catalyst bears the good stability. It means that nano-ZrO2 doped REOx catalyst might be a potential commercial catalyst for the NHP dehydration.展开更多
Using the first-principles calculations based on density functional theory(DFT),the structure stability,electronic and some optical properties of C and N doped cubic ZrO2(c-ZrO2) in 24-atom systems were investigated.I...Using the first-principles calculations based on density functional theory(DFT),the structure stability,electronic and some optical properties of C and N doped cubic ZrO2(c-ZrO2) in 24-atom systems were investigated.It is found from the formation energies calculations that N ions are easier to be doped into c-ZrO2 than C ions.The electronic structure results show that Zr8O15C and Zr8O15N systems are semiconductors with the band gap of 2.3 eV and 2.8 eV,respectively,which are lower than that of the pure ZrO2(3.349 eV).And optical properties results depict that anion doping,especially C adding,can enhance the static dielectric function,visible and ultraviolet light absorption and reflecting ability of c-ZrO2 crystal.展开更多
A series of V2O5‐WO3/TiO2‐ZrO2,V2O5‐WO3/TiO2‐CeO2,and V2O5‐WO3/TiO2‐CeO2‐ZrO2 catalysts were synthesized to improve the selective catalytic reduction(SCR)performance and the K‐poisoning resistance of a V2O5‐W...A series of V2O5‐WO3/TiO2‐ZrO2,V2O5‐WO3/TiO2‐CeO2,and V2O5‐WO3/TiO2‐CeO2‐ZrO2 catalysts were synthesized to improve the selective catalytic reduction(SCR)performance and the K‐poisoning resistance of a V2O5‐WO3/TiO2 catalyst.The physicochemical properties were investigated by using XRD,BET,NH3‐TPD,H2‐TPR,and XPS,and the catalytic performance and K‐poisoning resistance were evaluated via a NH3‐SCR model reaction.Ce^4+and Zr^4+co‐doping were found to enhance the conversion of NOx,and exhibit the best K‐poisoning resistance owing to the largest BET‐specific surface area,pore volume,and total acid site concentration,as well as the minimal effects on the surface acidity and redox ability from K poisoning.The V2O5‐WO3/TiO2‐CeO2‐ZrO2 catalyst also presents outstanding H2O+SO2 tolerance.Finally,the in situ DRIFTS reveals that the NH3‐SCR reaction over the V2O5‐WO3/TiO2‐CeO2‐ZrO2 catalyst follows an L‐H mechanism,and that K poisoning does not change the reaction mechanism.展开更多
基金supported by the National Natural Science Foundation of China(51272105)Jiangsu Provincial Science and Technology Supporting Program(BE2013718)+1 种基金Research Subject of Environmental Protection Department of Jiangsu Province of China(2013006)Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)~~
文摘A series CeO2（ZrO2）/TiO2 catalysts were modified with Er using a sol-gel method.The catalytic activity of the obtained catalysts in the selective catalytic reduction（SCR） of NO with NH3 was investigated to determine the appropriate Er dosage.The catalysts were characterized using X-ray diffraction,N2 adsorption,NH3 temperature-programmed desorption,H2 temperature-programmed reduction,photoluminescence spectroscopy,electron paramagnetic resonance spectroscopy,and X-ray photoelectron spectroscopy.The results showed that the optimum Er/Ce molar ratio was 0.10;this catalyst had excellent resistance to catalyst poisoning caused by vapor and sulfur and gave more than 90% NO conversion at 220–395 ℃ and a gas hourly space velocity of 71 400 h^-1.Er incorporation increased the Ti^3＋ concentrations,oxygen storage capacities,and oxygen vacancy concentrations of the catalysts,resulting in excellent catalytic performance.Er incorporation also decreased the acid strength and inhibited growth of TiO2 and CeO2 crystal particles,which increased the catalytic activity.The results show that high oxygen vacancy concentrations and oxygen storage capacities,large amounts of Ti^3＋,and low acid strengths give excellent SCR activity.
文摘Catalyst plays an important role in the dehydration of N-（hydroxylethyl）pyrrolidone （NHP） to prepare N-vinyl-pyrrolidone （NVP）. At present, NVP yield is only about 30% on commercial ZrO2 catalyst. A coupled precipitation and solid dispersion technique was designed to prepare the nano-ZrO2 catalyst, in which rare earth metal oxides （REOx） was used as electronic promoter. The results indicated that the catalyst doped REOx （S-1.0） exhibits the optimum performance of NHP dehydration at moderate conditions. NHP conversion and NVP selectivity are respectively 97.0%, 82.3%. Of special interest is that the indexes of the catalyst （S-1.0-1.0） are up to 98.4% and 89.2% respectively. Furthermore, this catalyst bears the good stability. It means that nano-ZrO2 doped REOx catalyst might be a potential commercial catalyst for the NHP dehydration.
基金Project(61172047) supported by the National Natural Science Foundation of China
文摘Using the first-principles calculations based on density functional theory(DFT),the structure stability,electronic and some optical properties of C and N doped cubic ZrO2(c-ZrO2) in 24-atom systems were investigated.It is found from the formation energies calculations that N ions are easier to be doped into c-ZrO2 than C ions.The electronic structure results show that Zr8O15C and Zr8O15N systems are semiconductors with the band gap of 2.3 eV and 2.8 eV,respectively,which are lower than that of the pure ZrO2(3.349 eV).And optical properties results depict that anion doping,especially C adding,can enhance the static dielectric function,visible and ultraviolet light absorption and reflecting ability of c-ZrO2 crystal.
基金supported by the National Natural Science Foundation of China(21876168,21507130)the Key Projects for Common Key Technology Innovation in Key Industries in Chongqing(cstc2016zdcy-ztzx0020-01)+2 种基金the Chongqing Science&Technology Commission(cstc2016jcyjA0070,cstckjcxljrc13)the Open Project Program of Chongqing Key Laboratory of Catalysis and Functional Organic Molecules from Chongqing Technology and Business University(1456029)the Graduate Innovation Project of Chongqing Technology and Business University(yjscxx201803-028-22)~~
文摘A series of V2O5‐WO3/TiO2‐ZrO2,V2O5‐WO3/TiO2‐CeO2,and V2O5‐WO3/TiO2‐CeO2‐ZrO2 catalysts were synthesized to improve the selective catalytic reduction(SCR)performance and the K‐poisoning resistance of a V2O5‐WO3/TiO2 catalyst.The physicochemical properties were investigated by using XRD,BET,NH3‐TPD,H2‐TPR,and XPS,and the catalytic performance and K‐poisoning resistance were evaluated via a NH3‐SCR model reaction.Ce^4+and Zr^4+co‐doping were found to enhance the conversion of NOx,and exhibit the best K‐poisoning resistance owing to the largest BET‐specific surface area,pore volume,and total acid site concentration,as well as the minimal effects on the surface acidity and redox ability from K poisoning.The V2O5‐WO3/TiO2‐CeO2‐ZrO2 catalyst also presents outstanding H2O+SO2 tolerance.Finally,the in situ DRIFTS reveals that the NH3‐SCR reaction over the V2O5‐WO3/TiO2‐CeO2‐ZrO2 catalyst follows an L‐H mechanism,and that K poisoning does not change the reaction mechanism.
