The effects of composite supports of CeO2-Al2O3, MgO-Al2O3, TiO2-Al2O3 or ZrO2-Al2O3 on the methanation activity of supported Co-Mo-based sulphur-resistant catalysts were investigated. The catalysts were further chara...The effects of composite supports of CeO2-Al2O3, MgO-Al2O3, TiO2-Al2O3 or ZrO2-Al2O3 on the methanation activity of supported Co-Mo-based sulphur-resistant catalysts were investigated. The catalysts were further characterized by nitrogen adsorption measurement, X-ray diffraction and X-ray photoelectron spectroscopy. The catalyst of 5%CoO-15%MoO3 supported on CeO2-Al2O3, MgO-Al2O3, TiO2-Al2O3 or ZrO2-Al2O3 composite oxides, respectively, showed different catalytic performances of syngas methanation in the presence of hydrogen sulphide as compared with that of the 5%CoO-15%MoO3/Al2O3 catalyst. The Co-Mo/CeO2-Al2O3 catalyst shows the highest methanation activity among the tested catalysts. The enhanced methanation activity may be attributed to the improvement of the dispersion of active metal species and the inhibition of the formation of S6＋.展开更多
Based on the γ-Al2O3 support with large-size pores, impregnation-deposition method was adopted to prepare the nano CeO_2/γ-Al2O3 composite supports. The results of XRD showed that there was no CeO_2-Al2O3 mixture or...Based on the γ-Al2O3 support with large-size pores, impregnation-deposition method was adopted to prepare the nano CeO_2/γ-Al2O3 composite supports. The results of XRD showed that there was no CeO_2-Al2O3 mixture or solid solution, indicating that CeO_2 was only loaded on the surface of Al2O3. The CeO_2/γ-Al2O3 composite support had larger specific surface area (170 m2·g-1), while for the non-loaded nanosized CeO_2, the specific surface area was small(～50 m2·g-1). The influence of impregnation and drying methods on the surface properties, thermal stability and crystal structure of composite supports was characterized by XRD, DTA and BET. The CeO_2/γ-Al2O3 composite support prepared by vacuum impregnation and microwave drying was better than that prepared by conventional impregnation and drying.展开更多
Laccase was immobilized on the ceramic-chitosan composite support by using glutaraldehyde as the cross-linking reagent. The immobilization conditions and characterization of the immobilized enzyme were investigated. T...Laccase was immobilized on the ceramic-chitosan composite support by using glutaraldehyde as the cross-linking reagent. The immobilization conditions and characterization of the immobilized enzyme were investigated. The immobilization of laccase was successfully realized when 3.0 mL of 1.25 mg/mL of laccase at a pH value of 4.0 reacted with 0.15 g of ceramic-chitosan composite support(CCCS) at 4 ℃ for 24 h. The immobilized enzyme exhibited a maximum activity at pH 3.0. The optimal temperatures for immobilized enzyme were 25 ℃ and 50 ℃. The K_m value of immobilized laccase for ABTS was 66.64 μmol/L at a pH value of 3.0 at 25 ℃. Compared with free laccase, the thermal, operating and storage stability of immobilized laccase was improved after the immobilization.展开更多
Aiming at reducing the deficiency of the traditional fire pre-warning algorithms and the intelligent fire pre-warning algorithms such as artificial neural network,and then to improve the accuracy of fire prewarning fo...Aiming at reducing the deficiency of the traditional fire pre-warning algorithms and the intelligent fire pre-warning algorithms such as artificial neural network,and then to improve the accuracy of fire prewarning for high-rise buildings,a composite fire pre-warning controller is designed according to the characteristic（ nonlinear,less historical data,many influence factors）,also a high-rise building fire pre-warning model is set up based on the support vector regression（ SV R）. Then the wood fire standard history data is applied to make empirical analysis. The research results can provide a reliable decision support framework for high-rise building fire pre-warning.展开更多
The effect of boron on the performance of MoO_3/CeO_2–Al_2O_3 catalysts, which were prepared with impregnation method, was investigated. The catalysts were characterized with N_2 adsorption–desorption, XRD, H_2-TPR,...The effect of boron on the performance of MoO_3/CeO_2–Al_2O_3 catalysts, which were prepared with impregnation method, was investigated. The catalysts were characterized with N_2 adsorption–desorption, XRD, H_2-TPR, and NH_3-TPD, and were tested in sulfur-resistant methanation. The results indicated that the MoO_3/CeO_2–Al_2O_3 catalysts modified by boron showed higher catalytic performance in sulfur-resistant methanation. The CO conversion increased from 47% to 62% with 0.5 wt% boron content. When the content of boron was under 0.5 wt%, the results suggested there was an increase in the amorphous form of MoO_3 caused by the generation of weak and intermediate acid sites, which had weakened the interaction between the active components and supports. While, the catalyst added 2.0 wt% boron showed the strong acid sites and the largest crystalline size resulting in the uneven distribution of ceria.展开更多
Composite oxide FeO x /Al 2 O 3 -supported gold catalysts were prepared by a modified two-step method. The effects of preparation conditions on the initial catalytic activity and long-time stability were studied for C...Composite oxide FeO x /Al 2 O 3 -supported gold catalysts were prepared by a modified two-step method. The effects of preparation conditions on the initial catalytic activity and long-time stability were studied for CO oxidation. XRD, XPS and in situ FTIR were employed to investigate the state of FeO x and the species on the catalyst surface. The results showed that Au/FeO x /Al 2 O 3 catalysts prepared by this method exhibited high activity and high stability in a wide pH value range. Calcination pretreatment was proved to be beneficial to improving the activity and stability. The beneficial effects of FeO x acting as a structural promoter could be ascribed to the ability to supply active oxygen species. As the precursor of FeO x , Fe（NO 3 ） 3 is superior to FeCl 3 for obtaining higher stability.展开更多
HZSM-5, Al_2O_3, TiO_2 and SiO_2 supported CeO_2-ZrO_2-CrO_x catalysts were prepared by deposition-precipitation method and tested for deep catalytic oxidation of 1,2-dichloroethane（DCE）, as one of the common chlori...HZSM-5, Al_2O_3, TiO_2 and SiO_2 supported CeO_2-ZrO_2-CrO_x catalysts were prepared by deposition-precipitation method and tested for deep catalytic oxidation of 1,2-dichloroethane（DCE）, as one of the common chlorinated organic pollutants. All the catalysts were characterized by means of N_2 adsorption-desorption, X-ray photoelectron spectroscopy（XPS）, ammonia-temperatureprogrammed desorption（NH_3-TPD） and hydrogen temperature-programmed reduction（H2-TPR）. The characterization results revealed that there was strongly synergistic effect between the oxidizability of CZCr species and the acidity of supports, which obviously promoted the catalytic activity for DCE degradation. 20% CZCr/HZSM-5 showed the highest activity and good durability during the long-term continuous test. The catalytic activity decreased in the order： 20%CZCr/HZSM-5〉CZCr〉20%CZCr/TiO_2〉20%CZCr/Al_2O_3〉20%CZCr/SiO_2.展开更多
A co-precipitation method was employed to prepare Ni/Al_(2)O_(3)-ZrO_(2),Co/Al_(2)O_(3)-ZrO_(2)and Ni-Co/Al_(2)O_(3)-ZrO_(2)catalysts.Their properties were characterized by N_(2) adsorption(BET),thermogravimetric anal...A co-precipitation method was employed to prepare Ni/Al_(2)O_(3)-ZrO_(2),Co/Al_(2)O_(3)-ZrO_(2)and Ni-Co/Al_(2)O_(3)-ZrO_(2)catalysts.Their properties were characterized by N_(2) adsorption(BET),thermogravimetric analysis(TGA),temperature-programmed reduction(TPR),temperature-programmed desorption(CO_(2)-TPD),and temperature-programmed surface reaction(CH_(4)-TPSR and CO_(2)-TPSR).Ni-Co/Al_(2)O_(3)-ZrO_(2)bimetallic catalyst has good performance in the reduction of active components Ni,Co and CO_(2)adsorption.Compared with mono-metallic catalyst,bimetallic catalyst could provide more active sites and CO_(2)adsorption sites(C+CO_(2)=2CO)for the methane-reforming reaction,and a more appropriate force formed between active components and composite support(SMSI)for the catalytic reaction.According to the CH_(4)-CO_(2)-TPSR,there were 80.9%and 81.5%higher CH_(4) and CO_(2)conversion over Ni-Co/Al_(2)O_(3)-ZrO_(2)catalyst,and its better resistance to carbon deposition,less than 0.5%of coke after 4 h reaction,was found by TGA.The high activity and excellent anti-coking of the Ni-Co/Al_(2)O_(3)-ZrO_(2)catalyst were closely related to the synergy between Ni and Co active metal,the strong metal-support interaction and the use of composite support.展开更多
文摘The effects of composite supports of CeO2-Al2O3, MgO-Al2O3, TiO2-Al2O3 or ZrO2-Al2O3 on the methanation activity of supported Co-Mo-based sulphur-resistant catalysts were investigated. The catalysts were further characterized by nitrogen adsorption measurement, X-ray diffraction and X-ray photoelectron spectroscopy. The catalyst of 5%CoO-15%MoO3 supported on CeO2-Al2O3, MgO-Al2O3, TiO2-Al2O3 or ZrO2-Al2O3 composite oxides, respectively, showed different catalytic performances of syngas methanation in the presence of hydrogen sulphide as compared with that of the 5%CoO-15%MoO3/Al2O3 catalyst. The Co-Mo/CeO2-Al2O3 catalyst shows the highest methanation activity among the tested catalysts. The enhanced methanation activity may be attributed to the improvement of the dispersion of active metal species and the inhibition of the formation of S6＋.
文摘Based on the γ-Al2O3 support with large-size pores, impregnation-deposition method was adopted to prepare the nano CeO_2/γ-Al2O3 composite supports. The results of XRD showed that there was no CeO_2-Al2O3 mixture or solid solution, indicating that CeO_2 was only loaded on the surface of Al2O3. The CeO_2/γ-Al2O3 composite support had larger specific surface area (170 m2·g-1), while for the non-loaded nanosized CeO_2, the specific surface area was small(～50 m2·g-1). The influence of impregnation and drying methods on the surface properties, thermal stability and crystal structure of composite supports was characterized by XRD, DTA and BET. The CeO_2/γ-Al2O3 composite support prepared by vacuum impregnation and microwave drying was better than that prepared by conventional impregnation and drying.
文摘Laccase was immobilized on the ceramic-chitosan composite support by using glutaraldehyde as the cross-linking reagent. The immobilization conditions and characterization of the immobilized enzyme were investigated. The immobilization of laccase was successfully realized when 3.0 mL of 1.25 mg/mL of laccase at a pH value of 4.0 reacted with 0.15 g of ceramic-chitosan composite support(CCCS) at 4 ℃ for 24 h. The immobilized enzyme exhibited a maximum activity at pH 3.0. The optimal temperatures for immobilized enzyme were 25 ℃ and 50 ℃. The K_m value of immobilized laccase for ABTS was 66.64 μmol/L at a pH value of 3.0 at 25 ℃. Compared with free laccase, the thermal, operating and storage stability of immobilized laccase was improved after the immobilization.
基金Supported by the National Natural Science Foundation of China(11072035)
文摘Aiming at reducing the deficiency of the traditional fire pre-warning algorithms and the intelligent fire pre-warning algorithms such as artificial neural network,and then to improve the accuracy of fire prewarning for high-rise buildings,a composite fire pre-warning controller is designed according to the characteristic（ nonlinear,less historical data,many influence factors）,also a high-rise building fire pre-warning model is set up based on the support vector regression（ SV R）. Then the wood fire standard history data is applied to make empirical analysis. The research results can provide a reliable decision support framework for high-rise building fire pre-warning.
基金Supported by the National High Technology Research and Development Program of China(863 Project)(2015AA050504)the National Natural Science Foundation of China(21576203)
文摘The effect of boron on the performance of MoO_3/CeO_2–Al_2O_3 catalysts, which were prepared with impregnation method, was investigated. The catalysts were characterized with N_2 adsorption–desorption, XRD, H_2-TPR, and NH_3-TPD, and were tested in sulfur-resistant methanation. The results indicated that the MoO_3/CeO_2–Al_2O_3 catalysts modified by boron showed higher catalytic performance in sulfur-resistant methanation. The CO conversion increased from 47% to 62% with 0.5 wt% boron content. When the content of boron was under 0.5 wt%, the results suggested there was an increase in the amorphous form of MoO_3 caused by the generation of weak and intermediate acid sites, which had weakened the interaction between the active components and supports. While, the catalyst added 2.0 wt% boron showed the strong acid sites and the largest crystalline size resulting in the uneven distribution of ceria.
基金supported by the Science and Research Reward Fund Program of Shandong Excellent Young Scientist of China (2007BS04033)
文摘Composite oxide FeO x /Al 2 O 3 -supported gold catalysts were prepared by a modified two-step method. The effects of preparation conditions on the initial catalytic activity and long-time stability were studied for CO oxidation. XRD, XPS and in situ FTIR were employed to investigate the state of FeO x and the species on the catalyst surface. The results showed that Au/FeO x /Al 2 O 3 catalysts prepared by this method exhibited high activity and high stability in a wide pH value range. Calcination pretreatment was proved to be beneficial to improving the activity and stability. The beneficial effects of FeO x acting as a structural promoter could be ascribed to the ability to supply active oxygen species. As the precursor of FeO x , Fe（NO 3 ） 3 is superior to FeCl 3 for obtaining higher stability.
基金Project supports from National Nature Science Foundation of China(21177110)
文摘HZSM-5, Al_2O_3, TiO_2 and SiO_2 supported CeO_2-ZrO_2-CrO_x catalysts were prepared by deposition-precipitation method and tested for deep catalytic oxidation of 1,2-dichloroethane（DCE）, as one of the common chlorinated organic pollutants. All the catalysts were characterized by means of N_2 adsorption-desorption, X-ray photoelectron spectroscopy（XPS）, ammonia-temperatureprogrammed desorption（NH_3-TPD） and hydrogen temperature-programmed reduction（H2-TPR）. The characterization results revealed that there was strongly synergistic effect between the oxidizability of CZCr species and the acidity of supports, which obviously promoted the catalytic activity for DCE degradation. 20% CZCr/HZSM-5 showed the highest activity and good durability during the long-term continuous test. The catalytic activity decreased in the order： 20%CZCr/HZSM-5〉CZCr〉20%CZCr/TiO_2〉20%CZCr/Al_2O_3〉20%CZCr/SiO_2.
基金supported by the National Basic Research Program of China(2005CB221207)the National Natural Science Foundation of China(Grants Nos.20846002,U0970134)+2 种基金the Program for Changjiang Scholars and Innovative Research Team in University(No.IRT0517)the Program for New Century Excellent Talents in University(No.NCET-05-0267)the Ph.D.Programs Foundation for New Teacher(No.20091402120013)in Ministry of Education,China。
文摘A co-precipitation method was employed to prepare Ni/Al_(2)O_(3)-ZrO_(2),Co/Al_(2)O_(3)-ZrO_(2)and Ni-Co/Al_(2)O_(3)-ZrO_(2)catalysts.Their properties were characterized by N_(2) adsorption(BET),thermogravimetric analysis(TGA),temperature-programmed reduction(TPR),temperature-programmed desorption(CO_(2)-TPD),and temperature-programmed surface reaction(CH_(4)-TPSR and CO_(2)-TPSR).Ni-Co/Al_(2)O_(3)-ZrO_(2)bimetallic catalyst has good performance in the reduction of active components Ni,Co and CO_(2)adsorption.Compared with mono-metallic catalyst,bimetallic catalyst could provide more active sites and CO_(2)adsorption sites(C+CO_(2)=2CO)for the methane-reforming reaction,and a more appropriate force formed between active components and composite support(SMSI)for the catalytic reaction.According to the CH_(4)-CO_(2)-TPSR,there were 80.9%and 81.5%higher CH_(4) and CO_(2)conversion over Ni-Co/Al_(2)O_(3)-ZrO_(2)catalyst,and its better resistance to carbon deposition,less than 0.5%of coke after 4 h reaction,was found by TGA.The high activity and excellent anti-coking of the Ni-Co/Al_(2)O_(3)-ZrO_(2)catalyst were closely related to the synergy between Ni and Co active metal,the strong metal-support interaction and the use of composite support.
