Exploitable results Improvement of nitrogen oxide reduction catalysts The main objective of this work was the development of new, better performing catalysts for the nitrogen oxide removal from the flue gases of stationary sources, by selective catalytic reduction (SCR). This target was achieved by: studying the influence of composition of active phase (kind and loading) on the catalytic performance; developing a new deposition methodology (equilibrium deposition filtration (EDF)) for deposition of active components on the support surface; using mixed titanium dioxide silicon dioxide as carriers of these catalysts; stabilizing the anatase structure of the carrier by incorporating tungsten (VI) ions in its lattice; studying a Cu-ZSM-5 catalyst for the nitrogen oxide reduction. In order to study the influence of the nature and the composition of the active phase in the catalytic performance, a series of vanadia titania, chromia titania and molybdena titania binary catalysts were prepared by the wet impregnation method and tested in the SCR of nitrogen oxide with ammonia. The superiority of the vanadia based catalysts against the other series was obvious, but gradual substitution of vanadium-phase by chromium or molybdenum, keeping the total loading constant, led to ternary catalysts more active than the corresponding binary ones. The application of different preparation procedures resulted in materials with different catalytic behaviour, although the support and the loading of the active phase were the same. Samples of vanadium oxide titanium dioxide catalysts, prepared by the equilibrium deposition filtration technique, found to be more active and selective than those prepared by the conventional wet impregnation method, in the SCR of nitrogen oxide with ammonia; this fact has been strengthened by the study of the reaction kinetics. With regard to the support, new vanadium titanium silicon nitrogen oxide reduction catalysts (powder and honeycomb type) were prepared, using a titanium dioxide silicon dioxide carrier, with titania compositions ranging between 0.5 and 3.0 monolayers. The catalysts were prepared by homogeneous precipitation of titanium (3+) on the surface and found to be highly active, with stronger mechanical properties, and higher surface area, than the commercial ones. Comparison of two vanadia-tungsten-titania catalysts showed that one of them, in which vanadia was supported in a mixed tungsten trioxide titanium dioxide, prepared by a sol-gel procedure, out-performs the conventional one, at intermediate reaction temperatures. Copper ions, alone or with rhodium ions exchanged into ZSM-5 at levels slightly in excess of that required for 100% proton replacement. Copper ZSM-5 catalyst significantly out-performed other commercial materials in the desired reaction at 473 K and 773 K. Searching for OpenAIRE data... There was an error trying to search data from OpenAIRE No results available
