Mechanistic investigation of the enhanced NH3-SCR on cobalt-decorated Ce-Ti mixed oxide: In situ FTIR analysis for structure-activity correlation
MetadataShow full item record
A series of transition metals (Co, Cu and Fe) were selected to decorate Ce-Ti mixed oxide to elevate the low-temperature activity of selective catalytic reduction of NOx by NH3 (NH3-SCR) reaction, by adjusting the ratio of surface Ce3+ species and oxygen vacancies. Among them, Co-Ce-Ti sample exhibited the excellent low-temperature activity and broadened temperature window, which could be attributed to the improvement of the physico-chemical properties and the acceleration of the reactions in the Langmuir-Hinshelwood (L-H) and Eley-Rideal (E-R) mechanisms. Owing to the different ionic sizes of Co2+ and Ce4+, the lattice distortion of Ce-Ti mixed oxide was greatly aggravated and subsequently increased the ratio of Ce3+ and the surface adsorbed oxygen, which benefited the generation of adsorbed NOx species and improved the reaction in the L-H mechanism. Meanwhile, the coordinatively unsaturated cationic sites over the Co-Ce-Ti sample induced more Lewis acid sites and enhanced the formation of the adsorbed NH3 species bounded with Lewis acid sites, which were considered as the crucial intermediates in E-R mechanism, and therefore facilitating the reaction between the adsorbed NH3 species and NO molecules. The enhancements in both the reactions from L-H and E-R mechanisms appeared to directly correlated with the improved deNOx performance on the Co-Ce-Ti sample, and the L-H mechanism could be the dominate one at low temperatures due to its rapid reaction rate.
Showing items related by title, author, creator and subject.
Catalytic partial oxidation of propylene to acrolein: the catalyst structure, reaction mechanisms and kineticsFansuri, Hamzah (2005)Bismuth molybdates have long been known as active catalysts for selective oxidation of olefins. There are several phases of bismuth molybdates but only three of them are known to be active for partial oxidation of propylene ...
Thermally assisted hydrolysis and derivatisation techniques for the characterisation of organic materialsChallinor, John M. (1998)This thesis describes the development of a novel method for the rapid identification of complex organic materials, including macromolecules, that involves a high temperature simultaneous hydrolysis and derivatisation ...
Co-precipitation of ferrihydrite and silica from acidic hydrometallurgical solutions and its impact on the paragoethite processDyer, Laurence G (2010)Ferrihydrite is a common iron oxyhydroxide, produced both naturally and industrially. It is often found in association with silica; an example of this is its occurrence in the Paragoethite process applied in zinc ...