A promising catalyst for catalytic oxidation of chlorobenzene and slipped ammonia in SCR exhaust gas: Investigating the simultaneous removal mechanism.

[Display omitted] • The competition adsorption mechanism of NH 3 and CB at low temperature is revealed. • Byproduct of NH 3 -SCO promotes deep oxidation of intermediates in CBCO reaction. • The forms of N and Cl species in simultaneous catalytic oxidation are unveiled. As the emission limits for NO x become further stringent, development of a synergistic control technology to prevent emissions of slipped ammonia (NH 3) and chlorinated organics from steel production and waste incineration is both a prospect and a challenge for the environmental issues. In this work, the designed ruthenium-based catalyst (RuNb/ST) showed the excellent chlorobenzene (CB)/NH 3 synergistic removal performance and N 2 /CO 2 selectivity above 300 ℃. The activity of NH 3 and CB were suppressed at relatively low temperature due to the competitive adsorption of CB and NH 3. Whereas, there was a significant improvement in the N 2 /CO 2 selectivity at relatively high temperature. The removal mechanism was studied by experiments, in which the accumulation of chlorine species, the role of NO 2 and the oxidation of CB were considerable. In contrast to the carrier, the vast majority of the chloride ions adsorbed onto the active sites after dissociating from CB could be efficiently removed in form of Cl 2 via the Deacon Reaction catalyzed by RuO 2. CB was predominantly converted into CO 2 and H 2 O with a fraction persisting as organics. Partial of organics were attacked by Cl ions to generate organic chlorine-containing by-products. The presence of NO 2 molecule was found to promote the cleavage of the benzene ring within CB, and expedited the carbon migration towards the ultimate product of CO 2 , resulting in a notable reduction of byproducts. [ABSTRACT FROM AUTHOR]