Influence of preparation methods of supports on the deNOx performance and alkali-metal resistance over TiO2/CeO2 catalysts in NH3-SCR reaction

Two kinds of CeO2 supports were synthesized by precipitation method and hydrothermal method, respectively, and then TiO2 species were loaded on their surface to prepare two TiO2/CeO2 catalysts (abbreviated as Ti/Ce-PM and Ti/Ce-HM). Experimental results show that Ti/Ce-PM and Ti/Ce-HM catalysts exhibit irregular nanoparticle morphology and specific tubular morphology, respectively, while the deNO(x) performance and anti-K poisoning ability of Ti/Ce-HM catalyst are worse than those of Ti/Ce-PM catalyst, which suggests that the random loading of TiO2 species on the tubular CeO(2 )support doesn't enhance the deNOx performance and alkali-metal resistance. However, physicochemical property characterizations display that the excellent deNO(x) performance of Ti/Ce-PM catalyst can be attributed to better dispersion of TiO2 species, more excellent redox performance and surface acidity (especially B acid), larger Ce3+ content and O alpha ratio, stronger electron interaction between Ce and Ti through the redox cycle of Ce3+ + Ti4+ ? Ce4+ + Ti3+, as well as easier desorption and decomposition of the adsorbed NOx species. Furthermore, stronger anti-K poisoning ability of Ti/Ce-PM catalyst results from that the negative impact of K2O species on the redox performance, surface acidity, Ce3+ content, and O alpha ratio of Ti/Ce-PM catalyst is smaller than that on Ti/Ce-HM catalyst.

Automated summary

Two kinds of TiO2/CeO2 catalysts with different morphologies were prepared by two different synthesis methods. It was found that random loading of TiO2 species on tubular CeO2 support did not enhance the catalyst performance, and the excellent catalytic performance was attributed to better dispersion of TiO2 species and superior physicochemical properties.