In this paper a new solid superacid catalyst SO 2- 4 MoO 3 TiO 2 was prepared.The activity of the catalyst in esterification of acetic acid and iso amyl alcohol was measured and compared with that of SO 2- 4 TiO 2 and...In this paper a new solid superacid catalyst SO 2- 4 MoO 3 TiO 2 was prepared.The activity of the catalyst in esterification of acetic acid and iso amyl alcohol was measured and compared with that of SO 2- 4 TiO 2 and MoO 3 TiO 2.The results showed that SO 2- 4 MoO 3 TiO 2 had better catalytic performance than SO 2- 4 TiO 2 and MoO 3 TiO 2.There was evident coordination between MoO 3 and SO 2- 4 when they coexisted on TiO 2.展开更多
The dispersion of K\-2CO\-3 on \%γ\%\|Al\-2O\-3 and the adsorption performance of K\-2CO\-3/\%γ\%\|Al\-2O\-3 to SO\-2 are investigated.The results show that K\-2CO\-3 can disperse onto the surface of \%γ\%\|Al\-2O\...The dispersion of K\-2CO\-3 on \%γ\%\|Al\-2O\-3 and the adsorption performance of K\-2CO\-3/\%γ\%\|Al\-2O\-3 to SO\-2 are investigated.The results show that K\-2CO\-3 can disperse onto the surface of \%γ\%\|Al\-2O\-3 as a monolayer and the dispersion threshold is 0.31\[\%m\%(K\-2CO\-3)/\%m\%(\%γ\%\|Al\-2O\-3), \%m\%/g\], which is close to the theoretical value calculated by assuming a bidentate vertical dispersion model of CO\-2 on the \%γ\%\|Al\-2O\-3 surface . The SO\-2 adsorption\|capacity on K\-2CO\-3/\%γ\%\|Al\-2O\-3 sample increases with the K\-2CO\-3 loading and reaches an extremum at its threshold. The adsorbent conversion of K\-2CO\-3/\%γ\%\|Al\-2O\-3 at the threshold is up to 72%. When the loading is higher than the threshold, the SO\-2 adsorption capacity decreases at first, then increases again. This phenomenon is caused by the reaction between SO\-2 and the bulk phase of K\-2CO\-3 crystallites. The sample decreases with the loading, and the sample with \{0.10\}\[\%m\%(K\-2CO\-3)/\%m(γ\%\|Al\-2O\-3), \%m\%/g\] loading shows the highest regeneration percentage of 63%. Compared with Na\-2CO\-3/\%γ\%\|Al\-2O\-3, K\-2CO\-3/\%γ\%\|Al\-2O\-3 might have some advantages.展开更多
This study was aimed to investigate the effects of hydrothermal aging, propene and SO<sub>2</sub> poisoning on the ammonia-selective catalytic reduction (NH<sub>3</sub>-SCR) performance of both...This study was aimed to investigate the effects of hydrothermal aging, propene and SO<sub>2</sub> poisoning on the ammonia-selective catalytic reduction (NH<sub>3</sub>-SCR) performance of both Cu-SAPO-34 and Cu-ZSM-5. The catalytic activities of fresh, aged and poisoned samples were tested in ammonia-selective catalytic reduction (NH<sub>3</sub>-SCR) of NO<sub>x</sub> conditions. The XRD, TG and N<sub>2</sub>-desorption results showed that the structures of the Cu-SAPO-34 and Cu-ZSM-5 remained intact after 750˚C hydrothermally aged, SO<sub>2</sub> and propene poisoned. After hydrothermal aging at 750˚C for 12 h, the NO reduction performance of Cu-ZSM-5 was significantly reduced at lower temperatures, while that of Cu-SAPO-34 was less affected. Moreover, Cu-SAPO-34 catalyst showed high NO conversion with SO<sub>2</sub> or propene compared to Cu-ZSM-5. However, Cu-ZSM-5 showed a larger drop in catalytic activity with SO<sub>2</sub> or propene compared to Cu-SAPO-34 catalyst. The H<sub>2</sub>-TPR results showed that Cu<sup>2 </sup> ions could be reduced to Cu<sup> </sup> and Cu<sup>0</sup> for Cu-ZSM-5, while no significant transformation of copper species was observed for Cu-SAPO-34. Meanwhile, the UV-vis DRS results showed that CuO species were formed in Cu-ZSM-5, while little changes were observed for the Cu-SAPO-34. Cu-SAPO-34 showed high sulfur and hydrocarbon poison resistance compared to Cu-ZSM-5. In summary, Cu-SAPO-34 with small-pore zeolite showed higher hydrothermal stability and better hydrocarbon and sulfur poison resistant than Cu-ZSM-5 with medium-pore.展开更多
文摘In this paper a new solid superacid catalyst SO 2- 4 MoO 3 TiO 2 was prepared.The activity of the catalyst in esterification of acetic acid and iso amyl alcohol was measured and compared with that of SO 2- 4 TiO 2 and MoO 3 TiO 2.The results showed that SO 2- 4 MoO 3 TiO 2 had better catalytic performance than SO 2- 4 TiO 2 and MoO 3 TiO 2.There was evident coordination between MoO 3 and SO 2- 4 when they coexisted on TiO 2.
文摘The dispersion of K\-2CO\-3 on \%γ\%\|Al\-2O\-3 and the adsorption performance of K\-2CO\-3/\%γ\%\|Al\-2O\-3 to SO\-2 are investigated.The results show that K\-2CO\-3 can disperse onto the surface of \%γ\%\|Al\-2O\-3 as a monolayer and the dispersion threshold is 0.31\[\%m\%(K\-2CO\-3)/\%m\%(\%γ\%\|Al\-2O\-3), \%m\%/g\], which is close to the theoretical value calculated by assuming a bidentate vertical dispersion model of CO\-2 on the \%γ\%\|Al\-2O\-3 surface . The SO\-2 adsorption\|capacity on K\-2CO\-3/\%γ\%\|Al\-2O\-3 sample increases with the K\-2CO\-3 loading and reaches an extremum at its threshold. The adsorbent conversion of K\-2CO\-3/\%γ\%\|Al\-2O\-3 at the threshold is up to 72%. When the loading is higher than the threshold, the SO\-2 adsorption capacity decreases at first, then increases again. This phenomenon is caused by the reaction between SO\-2 and the bulk phase of K\-2CO\-3 crystallites. The sample decreases with the loading, and the sample with \{0.10\}\[\%m\%(K\-2CO\-3)/\%m(γ\%\|Al\-2O\-3), \%m\%/g\] loading shows the highest regeneration percentage of 63%. Compared with Na\-2CO\-3/\%γ\%\|Al\-2O\-3, K\-2CO\-3/\%γ\%\|Al\-2O\-3 might have some advantages.
文摘This study was aimed to investigate the effects of hydrothermal aging, propene and SO<sub>2</sub> poisoning on the ammonia-selective catalytic reduction (NH<sub>3</sub>-SCR) performance of both Cu-SAPO-34 and Cu-ZSM-5. The catalytic activities of fresh, aged and poisoned samples were tested in ammonia-selective catalytic reduction (NH<sub>3</sub>-SCR) of NO<sub>x</sub> conditions. The XRD, TG and N<sub>2</sub>-desorption results showed that the structures of the Cu-SAPO-34 and Cu-ZSM-5 remained intact after 750˚C hydrothermally aged, SO<sub>2</sub> and propene poisoned. After hydrothermal aging at 750˚C for 12 h, the NO reduction performance of Cu-ZSM-5 was significantly reduced at lower temperatures, while that of Cu-SAPO-34 was less affected. Moreover, Cu-SAPO-34 catalyst showed high NO conversion with SO<sub>2</sub> or propene compared to Cu-ZSM-5. However, Cu-ZSM-5 showed a larger drop in catalytic activity with SO<sub>2</sub> or propene compared to Cu-SAPO-34 catalyst. The H<sub>2</sub>-TPR results showed that Cu<sup>2 </sup> ions could be reduced to Cu<sup> </sup> and Cu<sup>0</sup> for Cu-ZSM-5, while no significant transformation of copper species was observed for Cu-SAPO-34. Meanwhile, the UV-vis DRS results showed that CuO species were formed in Cu-ZSM-5, while little changes were observed for the Cu-SAPO-34. Cu-SAPO-34 showed high sulfur and hydrocarbon poison resistance compared to Cu-ZSM-5. In summary, Cu-SAPO-34 with small-pore zeolite showed higher hydrothermal stability and better hydrocarbon and sulfur poison resistant than Cu-ZSM-5 with medium-pore.
