Use of ethanol in the catalytic abatement of NOx

Oxygenated molecules have attracted increasing interest for the reduction of NO. In this work Pd–Bax/ZrO2 catalysts were investigated for the NOx reduction by ethanol. Catalysts were prepared for different Ba contents by incipient wetness impregnation and subsequently with Pd nitrate and characterized by several techniques. Temperature programmed NO desorption analyses revealed the existence of combined palladium and barium effects, suggesting involvement of multiple sites for the N2 formation. DRIFTS analyses strongly suggest the presence of two types of Ba sites, depending on the proximity of Ba and Pd atoms. Catalytic results of NO reduction by ethanol showed positive effect of barium towards N2 yield and high conversion of NO and ethanol. Particularly, the sample 1.5Pd23Ba exhibited very high N2 yields, which is related to the nitrite/nitrate formation and Pd–Ba interaction.

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► Pd–Ba/ZrO2 catalysts were investigated for the nitric oxide reduction by ethanol.
► Catalytic results showed effect of barium contents producing very high N2 yields.
► DRIFTS analyses suggested the presence of two types of Ba sites.
► Surface ionic nitrate and nitrites indicate multiple sites capable to capture NO.
► Evidence of reaction of NOx with Ba(OH)2 species.