铈锆复合氧化物催化HCl氧化中相互作用机制

ZrO₂/CeO₂ (xZr/Ce) and CeO₂/ZrO₂ (yCe/Zr)catalysts with different loading were prepared by wet impregnation method. XRD, Raman, N₂-Sorption, TEM and H₂-TPR were used to study the interaction between CeO₂ and ZrO₂ in the recycling of Cl₂ from HCl oxidation. The results showed that the doping appropriate amount of zirconium species on the surface of CeO₂ could increase the concentration of oxygen vacancy over xZr/Ce, which was in favor of enhancing the activity of HCl oxidation. When there were too many Zr⁴⁺ doping on the surface of CeO₂, a part of Zr elements would be presented as ZrO₂ over the surface of xZr/Ce and the oxygen vacancy was covered, which was unfavorable to the activity of HCl oxidation. For yCe/Zr catalyst, the dispersive CeO₂ over ZrO₂ was beneficial to the improvement of the catalytic activity, but the increase of catalytic activity would slow down when the loading of CeO₂ exceed 10%. By comparing xZr/Ce with yCe/Zr catalysts, the oxygen vacancy of xZr/Ce was mainly formed by Ce-Zr solid solution, while the oxygen vacancy of yCe/Zr was formed by highly dispersive CeO₂. It was found that the oxygen vacancy produced by different structure have different effects on the activity. The oxygen vacancies produced by Ce-Zr solid solution are more favorable to the activity enhancement. The ability of chlorine resistance of xZr/Ceand yCe/Zr catalysts behaved a superior stability in the long-term test compared to pure CeO₂.