Recently, owing to high costs and increasing demands for better catalysts, it is worthwhile to improve its activity and selectivity, and reduce its costs. Adding secondary promoters such as phosphorus, boron, magnesiu...Recently, owing to high costs and increasing demands for better catalysts, it is worthwhile to improve its activity and selectivity, and reduce its costs. Adding secondary promoters such as phosphorus, boron, magnesium, titanium, zinc and ruthenium to Co-Mo/Al;O;catalyst has been proved to be one of the ways to attain this result. The addition of those metals or metal oxides changes the surface states of molybdenumstructure.展开更多
The surface species formed from the adsorption of 1,3-butadiene and 1,3-butadiene hydrogenation over the fresh Mo2C/γ-Al2O3 catalyst was studied by in situ IR spectroscopy. It is found that 1,3-butadiene adsorption o...The surface species formed from the adsorption of 1,3-butadiene and 1,3-butadiene hydrogenation over the fresh Mo2C/γ-Al2O3 catalyst was studied by in situ IR spectroscopy. It is found that 1,3-butadiene adsorption on the Mo2C/γ-Al2O3 catalyst mainly forms π-adsorbed butadiene(πs and πd) and σ-bonded surface species. These species are adsorbed mainly on the surface Moδ+(0<δ<2) sites as evidenced by co-adsorption of 1,3-butadiene and CO on the fresh Mo2C/γ-Al2O3 catalyst. The IR spectrometric analysis show that hydrogenation of 1,3-butadiene over fresh Mo2C/γ-Al2O3 catalyst produces mainly butane coupled with a small portion of butene. The selectivity of butene during the hydrogenation of 1,3-butadiene over fresh Mo2C/γ-Al2O3 catalyst might be explained by the adsorption mode of adsorbed 1,3-butadiene. Additionally, the active sites of the fresh Mo2C/γ-Al2O3 catalyst may be covered by coke during the hydrogenation reaction of 1,3-butadiene. The treatment with hydrogen at 673 K cannot remove the coke deposits from the surface of the Mo2C/γ-Al2O3 catalyst.展开更多
Au/Al2O3 catalyst was prepared by a modified anion impregnation method and investigated with respect to its initial activity and stability for low-temperature CO oxidation.The activity changes of the catalyst were exa...Au/Al2O3 catalyst was prepared by a modified anion impregnation method and investigated with respect to its initial activity and stability for low-temperature CO oxidation.The activity changes of the catalyst were examined after separate treatment in CO＋O2 or CO2 ＋O2 .Furthermore,in situ FT-IR studies were performed to investigate the species on the surface when CO or CO＋O2 or CO2 ＋O2 was selected separately as adsorption gas.The results showed that Au/Al2O3 catalyst exhibited very high initial activity,but the catalytic activity was found to decrease gradually during CO oxidation with time on stream.And also,the activity of the catalyst declined after treatment in CO＋O2 or CO2 ＋O2 .The formation and accumulation of carbonate-like species during CO oxidation or treatment in CO＋O2 or CO2 ＋O2 might be mainly responsible for the activity decrease,which was reversible.展开更多
The novel bimetallic Sn-Im/Al2O3 catalysts prepared by three methods for NO reduction by propene were investigated. The results showed that the catalytic activity was enhanced significantly in the presence of H2O on s...The novel bimetallic Sn-Im/Al2O3 catalysts prepared by three methods for NO reduction by propene were investigated. The results showed that the catalytic activity was enhanced significantly in the presence of H2O on sol-gel catalyst, and the maximum NO conversion increased from 46% to 92%, even in the presence of 100 ppm SO2, NO conversion was still 80%.展开更多
An investigation on adsorption of NO on reduced Co-Mo/Al_2O_3 and Ru-Co-Mo/Al_2O_3 catalysts has been performed using FT-IR and MS spectroscopies. IR spectra of NO adsorption showed two bands at 1895 and 1800 cm_(-1),...An investigation on adsorption of NO on reduced Co-Mo/Al_2O_3 and Ru-Co-Mo/Al_2O_3 catalysts has been performed using FT-IR and MS spectroscopies. IR spectra of NO adsorption showed two bands at 1895 and 1800 cm_(-1), and NO--TPD profiles gave rise to several peaks at 353, 423 and 473 K, which are assigned to various Co-sites on the surface. Compared with Co-Mo/Al_2O_3, the adsorption rate, binding energy, and amount of NO adsorbed on Ru-Co-Mo/Al_2O_3 are very high.展开更多
The adsorbed state of propylene oxide on MgO,ZnO and Al2O3were studied by IR spectroscopy.The IR results of PO adsorbed on MgO showed the appearance of 3 080 cm-1and 1 644 cm-1characteristic adsorption bands,which att...The adsorbed state of propylene oxide on MgO,ZnO and Al2O3were studied by IR spectroscopy.The IR results of PO adsorbed on MgO showed the appearance of 3 080 cm-1and 1 644 cm-1characteristic adsorption bands,which attribute to alkylene species,and the epoxide ring of propylene oxide was preferentially opened at O-C（1） bond.PO adsorbed on Al2O3showed the appearance of 1106cm-1peaks,which attribute to C-O stretching vibration,and the epoxide ring was preferentially opened at O-C（2） bond.The adsorbed species formed on MgO and Al2O3had the stability to some extent.The results of PO adsorbed on ZnO showed no chemical absorption occuring on ZnO suface.展开更多
文摘Recently, owing to high costs and increasing demands for better catalysts, it is worthwhile to improve its activity and selectivity, and reduce its costs. Adding secondary promoters such as phosphorus, boron, magnesium, titanium, zinc and ruthenium to Co-Mo/Al;O;catalyst has been proved to be one of the ways to attain this result. The addition of those metals or metal oxides changes the surface states of molybdenumstructure.
基金financially supported by the National Natural Science Foundation of China(No.20903054)Liaoning Provincial Natural Science Foundation(No.2014020107)+1 种基金Program for Liaoning excellent talents in university(No.LJQ2014041)sponsored by the Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministry(SRF for ROCS,SEM)
文摘The surface species formed from the adsorption of 1,3-butadiene and 1,3-butadiene hydrogenation over the fresh Mo2C/γ-Al2O3 catalyst was studied by in situ IR spectroscopy. It is found that 1,3-butadiene adsorption on the Mo2C/γ-Al2O3 catalyst mainly forms π-adsorbed butadiene(πs and πd) and σ-bonded surface species. These species are adsorbed mainly on the surface Moδ+(0<δ<2) sites as evidenced by co-adsorption of 1,3-butadiene and CO on the fresh Mo2C/γ-Al2O3 catalyst. The IR spectrometric analysis show that hydrogenation of 1,3-butadiene over fresh Mo2C/γ-Al2O3 catalyst produces mainly butane coupled with a small portion of butene. The selectivity of butene during the hydrogenation of 1,3-butadiene over fresh Mo2C/γ-Al2O3 catalyst might be explained by the adsorption mode of adsorbed 1,3-butadiene. Additionally, the active sites of the fresh Mo2C/γ-Al2O3 catalyst may be covered by coke during the hydrogenation reaction of 1,3-butadiene. The treatment with hydrogen at 673 K cannot remove the coke deposits from the surface of the Mo2C/γ-Al2O3 catalyst.
基金supported by the Science and Research Reward Fund Program of Shandong Excellent Young Scientist of China (2007BS04033)
文摘Au/Al2O3 catalyst was prepared by a modified anion impregnation method and investigated with respect to its initial activity and stability for low-temperature CO oxidation.The activity changes of the catalyst were examined after separate treatment in CO＋O2 or CO2 ＋O2 .Furthermore,in situ FT-IR studies were performed to investigate the species on the surface when CO or CO＋O2 or CO2 ＋O2 was selected separately as adsorption gas.The results showed that Au/Al2O3 catalyst exhibited very high initial activity,but the catalytic activity was found to decrease gradually during CO oxidation with time on stream.And also,the activity of the catalyst declined after treatment in CO＋O2 or CO2 ＋O2 .The formation and accumulation of carbonate-like species during CO oxidation or treatment in CO＋O2 or CO2 ＋O2 might be mainly responsible for the activity decrease,which was reversible.
基金financially supported by National Natural Science Foundation of China(Grant No.20437010)National 863 Project.(NO.2004AA649150)
文摘The novel bimetallic Sn-Im/Al2O3 catalysts prepared by three methods for NO reduction by propene were investigated. The results showed that the catalytic activity was enhanced significantly in the presence of H2O on sol-gel catalyst, and the maximum NO conversion increased from 46% to 92%, even in the presence of 100 ppm SO2, NO conversion was still 80%.
基金Natural Science Foundation of Chinese Academy of Sciences.
文摘An investigation on adsorption of NO on reduced Co-Mo/Al_2O_3 and Ru-Co-Mo/Al_2O_3 catalysts has been performed using FT-IR and MS spectroscopies. IR spectra of NO adsorption showed two bands at 1895 and 1800 cm_(-1), and NO--TPD profiles gave rise to several peaks at 353, 423 and 473 K, which are assigned to various Co-sites on the surface. Compared with Co-Mo/Al_2O_3, the adsorption rate, binding energy, and amount of NO adsorbed on Ru-Co-Mo/Al_2O_3 are very high.
文摘The adsorbed state of propylene oxide on MgO,ZnO and Al2O3were studied by IR spectroscopy.The IR results of PO adsorbed on MgO showed the appearance of 3 080 cm-1and 1 644 cm-1characteristic adsorption bands,which attribute to alkylene species,and the epoxide ring of propylene oxide was preferentially opened at O-C（1） bond.PO adsorbed on Al2O3showed the appearance of 1106cm-1peaks,which attribute to C-O stretching vibration,and the epoxide ring was preferentially opened at O-C（2） bond.The adsorbed species formed on MgO and Al2O3had the stability to some extent.The results of PO adsorbed on ZnO showed no chemical absorption occuring on ZnO suface.
