Boreskov Institute of Catalysis of the Siberian Branch of Russian ...

PEROVSKITE CATALYSTS FOR NO REDUCTION WITH H 2S. Furfori, N. Russo, D. Fino, G. Saracco, V. SpecchiaDepartment of Material Science and Chemical Engineering, Politecnico di Torino,Corso Duca degli Abruzzi, 24 10129, TorinoTel./Fax: 011.564.4710/4699; corresponding author: debora.fino@polito.itPP-III-8IntroductionRoad transport is a major contributor of hydrocarbons (HC), nitrogen oxides (NO x ) andparticulate matter (PM). The prevalent technology available to control NO x emission is indeedthe selective catalytic reduction (SCR) by NH 3 . In the last years, the use of hydrocarbons, coexistingin the vehicle exhaust, as reducing agents has been extensively studied [1]. Hydrogencould be the most likely candidate as a reducing agent in the SCR reaction to abate NO xemissions in an excess oxygen environment, such as diesel engine exhaust; this possibility hasbeen reported by several researchers [2]. The high performance of H 2 -SCR reaction canjustify the employment of a reformer for H 2 generation from diesel fuel.In the present paper, the activity of perovskite catalysts belonging to the LaFeO 3 familywas investigated for the H 2 -SCR technology. On the basis of the obtained results, thesuitability of the mentioned catalysts for application in the treatment of the diesel exhaustswill be finally discussed.Experimental Campaign & ResultsA series of perovskite catalysts(La 0.8 Sr 0.2 FeO 3 , La 0.8 Sr 0.2 Fe 0.9 Pd 0.1 O 3 ,La 0.7 Sr 0.2 Ce 0.1 FeO 3 , Pd/La 0.7 Sr 0.2 Ce 0.1 FeO 3 ) havebeen prepared by Solution Combustion Synthesis(SCS) from an aqueous solution of metal nitratesprecursors and urea (acting as a sacrificial fuel).According to this method an easily-crumblingfoam of nano-sized particles (see Fig. 1) with high Fig. 1. FESEM picture of La 0.7 Sr 0.2 Ce 0.1 FeO 3 .specific surface area was obtained. Pd was then deposited via IWP [3] employing an aqueoussolution of Palladium nitrate. The prepared powder was dried in oven at 120°C for 12 hours,then calcined in air at 500°C for 5 hours in order to decompose the nitrate and obtain smalland well dispersed Palladium clusters on the perovskite surface.The catalysts were characterized (XRD, FESEM, BET) and tested in a fixed-bed quartzmicroreactor under an atmosphere of 1000 ppmv NO, 4000 ppmv H 2 , with 10% or without317