Catalisadores a Base de SrSnO3 puros e Dopados com N-2+ não ...

ABSTRACTJoão Jarllys Nóbrega de Souza; Advisors: Profª. Drª. Iêda MariaG. Santos, Prof. Dr. Ary da Silva Maia.This work involved the synthesis of an oxide with perovskite structure (ABO 3 ),the strontium stannate (SrSnO 3 ), with orthorhombic structure, space groupPbnm, by the polymeric precursor method. This material has been applied ascapacitor, sensor for gases as NO, CO, H 2 , humidity and it is actually beingstudied as a catalyst. At the beginning of this work, pure SrSnO 3 and dopedwith 10 mol % of nickel (Sr 0,9 SnNi 0,1 O 3 , SrSn 0,9 Ni 0,1 O 3, Sr 0,95 Sn 0,95 Ni 0,1 O 3 ) werecharacterized by thermal analysis (TG / DTA), infrared spectroscopy (IR),Ultraviolet-visible spectroscopy (UV-Vis), Raman spectroscopy, X-ray diffractionand surface area by BET method. The catalytic activity of the non-supportedmaterial was evaluated in the reduction reaction of nitrogen monoxide (NO) bycarbon monoxide (CO), followed by characterization by XRD, IR and Ramananalysis. The material calcined at 800°C presented SrCO 3 as secondary phase,with a reduction in its intensity when Ni 2+ replaces Sr 2+ in the lattice. Doping didnot lead to a meaningful change in the long range order by increased the shortrange order. The system best catalytic performance (SrSn 0,9 Ni 0,1 O 3 ) achievedapproximately 90% of conversion of CO into CO 2 and 85% of NO into N 2 . In thesecond part of the work catalysts were supported (10% mass, the active phase/support) on anatase, gamma alumina, ceria and zirconia, using the resinobtained by the polymeric precursor method, with characterization as describedbefore. This procedure aimed at evaluating the effect of the support in theactivity of perovskite for the same reaction conditions. It was possible to confirmthe catalyst deposition on all supports, in spite of the difficulty in thecharacterization as a film was formed on the powder surface, leading tosuperposition of peaks/bands.Key-words: SrSnO 3 , perovskite, polymeric precursor method, supports, catalyticreduction of NO by CO.vi