TiO_2 modified Al_2O_3 binary oxide was prepared by a wet-impregnation method and used as the support for ruthenium catalyst. The catalytic performance of Ru/TiO_2–Al_2O_3catalyst in CO_2 methanation reaction was inv...TiO_2 modified Al_2O_3 binary oxide was prepared by a wet-impregnation method and used as the support for ruthenium catalyst. The catalytic performance of Ru/TiO_2–Al_2O_3catalyst in CO_2 methanation reaction was investigated. Compared with Ru/Al_2O_3 catalyst, the Ru/TiO_2–Al_2O_3catalytic system exhibited a much higher activity in CO_2 methanation reaction. The reaction rate over Ru/TiO_2–Al_2O_3 was 0.59 mol CO_2·(g Ru)1·h-1, 3.1 times higher than that on Ru/Al_2O_3[0.19 mol CO_2·(gRu)-1·h-1]. The effect of TiO_2 content and TiO_2–Al_2O_3calcination temperature on catalytic performance was addressed. The corresponding structures of each catalyst were characterized by means of H_2-TPR, XRD, and TEM. Results indicated that the averaged particle size of the Ru on TiO_2–Al_2O_3support is 2.8 nm, smaller than that on Al_2O_3 support of 4.3 nm. Therefore, we conclude that the improved activity over Ru/TiO_2–Al_2O_3catalyst is originated from the smaller particle size of ruthenium resulting from a strong interaction between Ru and the rutile-TiO_2 support, which hindered the aggregation of Ru nanoparticles.展开更多
Large surface areas nano-scale zirconia was prepared by the self-assembly route and was employed as support in nickel catalysts for the CO selective methanation. The effects of Ni loading and the catalyst calcination ...Large surface areas nano-scale zirconia was prepared by the self-assembly route and was employed as support in nickel catalysts for the CO selective methanation. The effects of Ni loading and the catalyst calcination temperature on the performance of the catalyst for CO selective methanation reaction were investigated. The cata- lysts were characterized by Brunauer-Emmett-Teller （BET）, transmission electron microscope （TEM）, X-ray dif- fraction （XRD） and temperature-programmed reduction （TPR）. The results showed that the as-synthesized Ni/nano-ZrO2 catalysts presented high activity for CO methanation due to the interaction between Ni active particle and nano zir- conia support. The selectivity for the CO methanation influenced significantly by the particle size of the active Ni species. The exorbitant calcination resulted in the conglomeration of dispersive Ni particles and led to the decrease of CO methanation selectivity. Among the catalysts studied, the 7.5% （by mass） Ni/ZrO2 catalyst calcinated at 500℃ was the most effective for the CO selective methanation. It can preferentially catalyze the CO methanation with a higher 99% conversion in the CO/CO2 competitive methanation system over the temperature range of 260-280℃, while keeping the CO2 conversion relatively low.展开更多
Three-dimensionally ordered macroporous(3DOM)perovskite materials have attracted the interest from researchers worldwide due to their unique macroporous structure,flexible composition,tailorable physicochemical proper...Three-dimensionally ordered macroporous(3DOM)perovskite materials have attracted the interest from researchers worldwide due to their unique macroporous structure,flexible composition,tailorable physicochemical property,high stability and biocompatibility.In particular,they were widely used in environmental field,such as photocatalysis,catalytic combustion,catalytic oxidation and sensors.In this review,the recent progresses in the synthesis of 3DOM perovskite materials and their environmental applications are summarized.The advantages and the promoting mechanisms of 3DOM perovskite materials for different applications are discussed in detail.Subsequently,the challenges and perspectives on the topic are proposed.展开更多
Methane (CH4) and carbon dioxide (CO2) emission was measured from mires in the Sanjiang Plain, Northeast China, by using a static chamber technique during free snow-covered periods. The seasonal mean emission of CH4 w...Methane (CH4) and carbon dioxide (CO2) emission was measured from mires in the Sanjiang Plain, Northeast China, by using a static chamber technique during free snow-covered periods. The seasonal mean emission of CH4 was 12.4mg/(m2·h) and the emission range of CO2 was 8.7-16.6g/(m2·d) (gross CO2 flux) during plant growth period. CO2 emission rate in the day was stronger than that at night, and the daily peak appears at 19:00. The mire plants in the Sanjiang Plain begin to sprout at the end of April. The aboveground biomass of the mire plants increased from zero to the peak from July to September and showed single peak form. The aboveground biomass of Carex lasiocarpa (464.8g/m2) was lower than that of Deyeuxia platyphylla (530.8g/m2), but the underground biomass was higher than that of Deyeuxia platyphylla. Gross CO2 flux showed the significance positive correlation relationship with plant biomass. Gross CO2 flux and CH4 emission were also correlated with soil temperature (0-5cm) and water temperature. However, the highest CH4 emission rate lagged behind the highest soil temperature in the root area during plant growth period. The data also indicated that wet and warm conditions during the early spring led to greater value of CH4 emission flux. Inundation is the necessary condition for the existence of methane bacteria, but there is no significant positive correlation between the inundation depth and CH4 emission rate in this region. Within the same growing season and under the same inundation condition, the variations of CH4 emission rate could be markedly different.展开更多
基金Supported by the National Natural Science Foundation of China(211031735127108721476226 and 51471076)DICP Fundamental Research Program for Clean Energy(DICPM201307)
文摘TiO_2 modified Al_2O_3 binary oxide was prepared by a wet-impregnation method and used as the support for ruthenium catalyst. The catalytic performance of Ru/TiO_2–Al_2O_3catalyst in CO_2 methanation reaction was investigated. Compared with Ru/Al_2O_3 catalyst, the Ru/TiO_2–Al_2O_3catalytic system exhibited a much higher activity in CO_2 methanation reaction. The reaction rate over Ru/TiO_2–Al_2O_3 was 0.59 mol CO_2·(g Ru)1·h-1, 3.1 times higher than that on Ru/Al_2O_3[0.19 mol CO_2·(gRu)-1·h-1]. The effect of TiO_2 content and TiO_2–Al_2O_3calcination temperature on catalytic performance was addressed. The corresponding structures of each catalyst were characterized by means of H_2-TPR, XRD, and TEM. Results indicated that the averaged particle size of the Ru on TiO_2–Al_2O_3support is 2.8 nm, smaller than that on Al_2O_3 support of 4.3 nm. Therefore, we conclude that the improved activity over Ru/TiO_2–Al_2O_3catalyst is originated from the smaller particle size of ruthenium resulting from a strong interaction between Ru and the rutile-TiO_2 support, which hindered the aggregation of Ru nanoparticles.
基金Supported by the National Natural Science Foundation of China(21276054,21376280)
文摘Large surface areas nano-scale zirconia was prepared by the self-assembly route and was employed as support in nickel catalysts for the CO selective methanation. The effects of Ni loading and the catalyst calcination temperature on the performance of the catalyst for CO selective methanation reaction were investigated. The cata- lysts were characterized by Brunauer-Emmett-Teller （BET）, transmission electron microscope （TEM）, X-ray dif- fraction （XRD） and temperature-programmed reduction （TPR）. The results showed that the as-synthesized Ni/nano-ZrO2 catalysts presented high activity for CO methanation due to the interaction between Ni active particle and nano zir- conia support. The selectivity for the CO methanation influenced significantly by the particle size of the active Ni species. The exorbitant calcination resulted in the conglomeration of dispersive Ni particles and led to the decrease of CO methanation selectivity. Among the catalysts studied, the 7.5% （by mass） Ni/ZrO2 catalyst calcinated at 500℃ was the most effective for the CO selective methanation. It can preferentially catalyze the CO methanation with a higher 99% conversion in the CO/CO2 competitive methanation system over the temperature range of 260-280℃, while keeping the CO2 conversion relatively low.
基金supported by the Tianjin Municipal Natural Science Foundation(17JCYBJC22600)the Fundamental Research Funds for the Central Universities~~
文摘Three-dimensionally ordered macroporous(3DOM)perovskite materials have attracted the interest from researchers worldwide due to their unique macroporous structure,flexible composition,tailorable physicochemical property,high stability and biocompatibility.In particular,they were widely used in environmental field,such as photocatalysis,catalytic combustion,catalytic oxidation and sensors.In this review,the recent progresses in the synthesis of 3DOM perovskite materials and their environmental applications are summarized.The advantages and the promoting mechanisms of 3DOM perovskite materials for different applications are discussed in detail.Subsequently,the challenges and perspectives on the topic are proposed.
文摘Methane (CH4) and carbon dioxide (CO2) emission was measured from mires in the Sanjiang Plain, Northeast China, by using a static chamber technique during free snow-covered periods. The seasonal mean emission of CH4 was 12.4mg/(m2·h) and the emission range of CO2 was 8.7-16.6g/(m2·d) (gross CO2 flux) during plant growth period. CO2 emission rate in the day was stronger than that at night, and the daily peak appears at 19:00. The mire plants in the Sanjiang Plain begin to sprout at the end of April. The aboveground biomass of the mire plants increased from zero to the peak from July to September and showed single peak form. The aboveground biomass of Carex lasiocarpa (464.8g/m2) was lower than that of Deyeuxia platyphylla (530.8g/m2), but the underground biomass was higher than that of Deyeuxia platyphylla. Gross CO2 flux showed the significance positive correlation relationship with plant biomass. Gross CO2 flux and CH4 emission were also correlated with soil temperature (0-5cm) and water temperature. However, the highest CH4 emission rate lagged behind the highest soil temperature in the root area during plant growth period. The data also indicated that wet and warm conditions during the early spring led to greater value of CH4 emission flux. Inundation is the necessary condition for the existence of methane bacteria, but there is no significant positive correlation between the inundation depth and CH4 emission rate in this region. Within the same growing season and under the same inundation condition, the variations of CH4 emission rate could be markedly different.
