Alkali metal K in exhaust gas has a deactivation effect on NH_(3)-SCR catalysts.In this work,it is discovered that the addition of Ho on CeTi catalyst can remarkably strengthen its K tolerance.The conclusions of Bruna...Alkali metal K in exhaust gas has a deactivation effect on NH_(3)-SCR catalysts.In this work,it is discovered that the addition of Ho on CeTi catalyst can remarkably strengthen its K tolerance.The conclusions of Brunauer-Emmett-Teller(BET),X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),NH_(3) temperature programmed desorption(NH_(3)-TPD)and H_(2)temperature programmed reduction(H_(2)-TPR)analyses demonstrate that the enhancement of K resistance mainly originates from its stronger surface acidity and redox capability,the higher concentration of Ce^(3+)species and surface chemisorbed oxygen.In situ DRIFT analysis reveals that the introduction of Ho on CeTi can remarkably improve the adsorption of NH_(3) and NO_(x) species on catalyst surface,accompanied by the intensified reactivity of ad-NH_(3) species,which should also administer to improve the K resistance.展开更多
Highly efficient photocatalytic reduction of CO2 is essential for solving the greenhouse effect and energy crisis.In this paper,the Sm-TiO2 nanocomposites were successfully prepared via sol-gel method.The CO2 photored...Highly efficient photocatalytic reduction of CO2 is essential for solving the greenhouse effect and energy crisis.In this paper,the Sm-TiO2 nanocomposites were successfully prepared via sol-gel method.The CO2 photoreduction activities of synthesized samples were tested under irradiation for 6 h and the results indicate that the 0.5% Sm-TiO2 catalyst has superior performance and stability.The CO and CH4 yields of0.5% Sm-TiO2 catalyst are 55.47 and 3.82 μmol/g·cat respectively,which are 5.02 and 2.67 times the yield of TiO2.The possible mechanism of Sm doped TiO2 was investigated through comprehensive characterization and photoetectrochemical analysis,After the Sm doping,the photo-generated electrons in TiO2 could migrate to Sm 4 f,and some of them can be captured by reducing Sm3+ o Sm2+,which can lower the recombination rate of electron and hole pairs.Therefore,the enhanced photocatalytic performance could be ascribed to large specific surface area,fast separation rate of electron-hole pairs and high visible light response.This report provides some meaningful attempts in researching the CO2 photocatalytic reduction.展开更多
Catalytic oxidation of NO into NO2 is a promising method for NOx emission control. The aim of this study was to de-velop an economic and environmental-friendly catalyst for NO catalytic oxidation. Herein a CeFeOx comp...Catalytic oxidation of NO into NO2 is a promising method for NOx emission control. The aim of this study was to de-velop an economic and environmental-friendly catalyst for NO catalytic oxidation. Herein a CeFeOx complex oxide catalyst for catalytic oxidation of NO was prepared by coprecipitation method. After that the catalytic performance of this catalyst was meas-ured on a fixed-bed reactor. It was found that the intrinsic activity of CeFeOx was higher than that of CeOx and FeOx. The charac-terization techniques of Brumauer-Emmett-Teller （BET）, X-ray diffraction （XRD）, temperature programmed reduction with H2 （H2-TPR）, temperature programmed desorption with NO＋O2 （NO＋O2-TPD） and X-ray photoelectron spectroscopy （XPS） were performed to investigate the surface area, crystal structure, redox property and NOx adsorption behavior of the catalyst samples. From the characterization results, it was concluded that the low crystallinity of CeFeOx promoted the dispersion of active species, as a result, enhancing the redox ability and NO adsorption capacity of CeFeOx catalyst, which is favorable to NO catalytic oxida-tion. Furthermore, the presence of much chemisorbed oxygen on CeFeOx catalyst also made a great contribution to its good cata-lytic performance.展开更多
To investigate the effect of CeOnanomaterial morphology on its performance for NO catalytic oxidation.Three kinds of CeOnanomaterials including CeOnanorods,nanospheres and nanoparticles were prepared by hydrothermal m...To investigate the effect of CeOnanomaterial morphology on its performance for NO catalytic oxidation.Three kinds of CeOnanomaterials including CeOnanorods,nanospheres and nanoparticles were prepared by hydrothermal method and used for catalytic oxidation of NO at low temperature. The experimental results show that CeOnanorods are of the best catalytic performance. Characterization techniques including TEM, XRD, H-TPR, NO-TPD and XPS were used to determine the relationship between the morphology of CeOnanomaterial and its catalytic performance. TEM images show that CeOnanorods predominantly exposed(110) and(10 0) planes, while CeOnanospheres and CeOnanoparticles predominantly exposed(111) plane. The excellent catalytic performance of CeOnanorods could be ascribed to the low crystallinity, high reducibility, strong NO adsorption ability and the presence of more surface chemisorbed oxygen.展开更多
基金Project supported by the National Key R&D Program of China(2018YFB0605002)。
文摘Alkali metal K in exhaust gas has a deactivation effect on NH_(3)-SCR catalysts.In this work,it is discovered that the addition of Ho on CeTi catalyst can remarkably strengthen its K tolerance.The conclusions of Brunauer-Emmett-Teller(BET),X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),NH_(3) temperature programmed desorption(NH_(3)-TPD)and H_(2)temperature programmed reduction(H_(2)-TPR)analyses demonstrate that the enhancement of K resistance mainly originates from its stronger surface acidity and redox capability,the higher concentration of Ce^(3+)species and surface chemisorbed oxygen.In situ DRIFT analysis reveals that the introduction of Ho on CeTi can remarkably improve the adsorption of NH_(3) and NO_(x) species on catalyst surface,accompanied by the intensified reactivity of ad-NH_(3) species,which should also administer to improve the K resistance.
基金Project supported by the National Key R&D Program of China(2018YFB0605002)the National Natural Science Foundation of Shanghai(14ZR1417800)。
文摘Highly efficient photocatalytic reduction of CO2 is essential for solving the greenhouse effect and energy crisis.In this paper,the Sm-TiO2 nanocomposites were successfully prepared via sol-gel method.The CO2 photoreduction activities of synthesized samples were tested under irradiation for 6 h and the results indicate that the 0.5% Sm-TiO2 catalyst has superior performance and stability.The CO and CH4 yields of0.5% Sm-TiO2 catalyst are 55.47 and 3.82 μmol/g·cat respectively,which are 5.02 and 2.67 times the yield of TiO2.The possible mechanism of Sm doped TiO2 was investigated through comprehensive characterization and photoetectrochemical analysis,After the Sm doping,the photo-generated electrons in TiO2 could migrate to Sm 4 f,and some of them can be captured by reducing Sm3+ o Sm2+,which can lower the recombination rate of electron and hole pairs.Therefore,the enhanced photocatalytic performance could be ascribed to large specific surface area,fast separation rate of electron-hole pairs and high visible light response.This report provides some meaningful attempts in researching the CO2 photocatalytic reduction.
基金Project supported by National Natural Science Foundation of China(21546014)the Natural Science Foundation of Shanghai(14ZR1417800)
文摘Catalytic oxidation of NO into NO2 is a promising method for NOx emission control. The aim of this study was to de-velop an economic and environmental-friendly catalyst for NO catalytic oxidation. Herein a CeFeOx complex oxide catalyst for catalytic oxidation of NO was prepared by coprecipitation method. After that the catalytic performance of this catalyst was meas-ured on a fixed-bed reactor. It was found that the intrinsic activity of CeFeOx was higher than that of CeOx and FeOx. The charac-terization techniques of Brumauer-Emmett-Teller （BET）, X-ray diffraction （XRD）, temperature programmed reduction with H2 （H2-TPR）, temperature programmed desorption with NO＋O2 （NO＋O2-TPD） and X-ray photoelectron spectroscopy （XPS） were performed to investigate the surface area, crystal structure, redox property and NOx adsorption behavior of the catalyst samples. From the characterization results, it was concluded that the low crystallinity of CeFeOx promoted the dispersion of active species, as a result, enhancing the redox ability and NO adsorption capacity of CeFeOx catalyst, which is favorable to NO catalytic oxida-tion. Furthermore, the presence of much chemisorbed oxygen on CeFeOx catalyst also made a great contribution to its good cata-lytic performance.
基金supported by National Natural Science Foundation of China(21546014)the Natural Science Foundation of Shanghai(14ZR1417800)
文摘To investigate the effect of CeOnanomaterial morphology on its performance for NO catalytic oxidation.Three kinds of CeOnanomaterials including CeOnanorods,nanospheres and nanoparticles were prepared by hydrothermal method and used for catalytic oxidation of NO at low temperature. The experimental results show that CeOnanorods are of the best catalytic performance. Characterization techniques including TEM, XRD, H-TPR, NO-TPD and XPS were used to determine the relationship between the morphology of CeOnanomaterial and its catalytic performance. TEM images show that CeOnanorods predominantly exposed(110) and(10 0) planes, while CeOnanospheres and CeOnanoparticles predominantly exposed(111) plane. The excellent catalytic performance of CeOnanorods could be ascribed to the low crystallinity, high reducibility, strong NO adsorption ability and the presence of more surface chemisorbed oxygen.
