A novel NOx storage/reductiou catalyst 12CaO·7Al2O3/10%K, defined as C12A7/K, was prepared, which possesses good NOx storage/reduction ability with a high sulfur-tolerance. The effect of H2O on the NO reduction f...A novel NOx storage/reductiou catalyst 12CaO·7Al2O3/10%K, defined as C12A7/K, was prepared, which possesses good NOx storage/reduction ability with a high sulfur-tolerance. The effect of H2O on the NO reduction features over the C12A7/K catalyst was investigated, The NO eonversion and the N2 selectivity were measured as a function of temperature and H2O concentration. In the presence of 1.2% H2O, both the NO conversion and the N2 selectivity significantly decrease at lower temperature region （〈500 ℃）. At temperatures over 500℃, however, the NO reduction is only slightly influenced by H2O, The species of NO3^-/NO2^- are confirmed as main storage components in the C12A7/K catalyst, which are thrther reduced into N2 by H2 under the reduction conditions.展开更多
Alkali and alkaline‐earth metals from fly ash have a significant deactivation effect on catalysts used for selective catalytic reduction of NOx by NH3(NH3‐SCR).Bromides are considered effective additives to improve ...Alkali and alkaline‐earth metals from fly ash have a significant deactivation effect on catalysts used for selective catalytic reduction of NOx by NH3(NH3‐SCR).Bromides are considered effective additives to improve Hg0 oxidation on SCR catalysts.In this work,the effects of different bromides(NH4Br,NaBr,KBr,and CaBr2)on a commercial V2O5‐WO3/TiO2 catalyst were studied.NOx conversion decreased significantly over the KBr‐poisoned catalyst(denoted as L‐KBr),while that over NaBr‐and CaBr2‐poisoned catalysts(denoted as L‐NaBr and L‐CaBr,respectivity)decreased to a lesser extent compared with the fresh sample.Poor N2 selectivity was observed over L‐NaBr,L‐KBr and L‐CaBr catalysts.The decrease in the ratio of chemisorbed oxygen to total surface oxygen(Oα/(Oα+Oβ+Ow)),reducibility and surface acidity might contribute to the poor activity and N2 selectivity over L‐KBr catalyst.The increased Oαratio was conducive to the enhanced reducibility of L‐CaBr.Combined with enhanced surface acidity,this might offset the negative effect of the loss of active sites by CaBr2 covering.The overoxidation of NH3 and poor N2 selectivity in NH3 oxidation should retard the SCR activity at high temperatures over L‐CaBr catalyst.The increased basicity might contribute to increased NOx adsorption on L‐KBr and L‐CaBr catalysts.A correlation between the acid‐basic and redox properties of bromide‐poisoned catalysts and their catalytic properties is established.展开更多
An efficient new method has been developed to synthesize N2‐alkyl 1,2,3‐triazole products by tol‐uenesulfonic acid （TsOH） catalyzed addition of N1‐Ts substituted 1,2,3‐triazoles to olefins. The reac‐tions of m...An efficient new method has been developed to synthesize N2‐alkyl 1,2,3‐triazole products by tol‐uenesulfonic acid （TsOH） catalyzed addition of N1‐Ts substituted 1,2,3‐triazoles to olefins. The reac‐tions of monosubstituted and unsubstituted triazole substrates with various olefins, including vinyl esters, are explored.展开更多
基金The project was supported by the National Natural Science Foundation of China(21173153)National High-Tech Research and Development Program of China(863)(2013AA065304)Major Research Program of Sichuan Province Science and Technology Department,China(2011GZ0035,2012FZ0008)~~
文摘A novel NOx storage/reductiou catalyst 12CaO·7Al2O3/10%K, defined as C12A7/K, was prepared, which possesses good NOx storage/reduction ability with a high sulfur-tolerance. The effect of H2O on the NO reduction features over the C12A7/K catalyst was investigated, The NO eonversion and the N2 selectivity were measured as a function of temperature and H2O concentration. In the presence of 1.2% H2O, both the NO conversion and the N2 selectivity significantly decrease at lower temperature region （〈500 ℃）. At temperatures over 500℃, however, the NO reduction is only slightly influenced by H2O, The species of NO3^-/NO2^- are confirmed as main storage components in the C12A7/K catalyst, which are thrther reduced into N2 by H2 under the reduction conditions.
基金supported by the National Key R&D Program of China(2016YFC0203900,2016YFC0203901)National Natural Science Foundation of China(51778619,21577173)~~
文摘Alkali and alkaline‐earth metals from fly ash have a significant deactivation effect on catalysts used for selective catalytic reduction of NOx by NH3(NH3‐SCR).Bromides are considered effective additives to improve Hg0 oxidation on SCR catalysts.In this work,the effects of different bromides(NH4Br,NaBr,KBr,and CaBr2)on a commercial V2O5‐WO3/TiO2 catalyst were studied.NOx conversion decreased significantly over the KBr‐poisoned catalyst(denoted as L‐KBr),while that over NaBr‐and CaBr2‐poisoned catalysts(denoted as L‐NaBr and L‐CaBr,respectivity)decreased to a lesser extent compared with the fresh sample.Poor N2 selectivity was observed over L‐NaBr,L‐KBr and L‐CaBr catalysts.The decrease in the ratio of chemisorbed oxygen to total surface oxygen(Oα/(Oα+Oβ+Ow)),reducibility and surface acidity might contribute to the poor activity and N2 selectivity over L‐KBr catalyst.The increased Oαratio was conducive to the enhanced reducibility of L‐CaBr.Combined with enhanced surface acidity,this might offset the negative effect of the loss of active sites by CaBr2 covering.The overoxidation of NH3 and poor N2 selectivity in NH3 oxidation should retard the SCR activity at high temperatures over L‐CaBr catalyst.The increased basicity might contribute to increased NOx adsorption on L‐KBr and L‐CaBr catalysts.A correlation between the acid‐basic and redox properties of bromide‐poisoned catalysts and their catalytic properties is established.
基金supported by the National Natural Science Foundation of China (21272268 and 21472237)~~
文摘An efficient new method has been developed to synthesize N2‐alkyl 1,2,3‐triazole products by tol‐uenesulfonic acid （TsOH） catalyzed addition of N1‐Ts substituted 1,2,3‐triazoles to olefins. The reac‐tions of monosubstituted and unsubstituted triazole substrates with various olefins, including vinyl esters, are explored.
