Steam effects over Pd/Ce_0.67Zr_0.33O₂ three-way catalyst

王建强^1,2，沈美庆^1,3，王军¹，王务林²

1. Key Laboratory for Green Chemical Technology of State Education Ministry,School of Chemical Engineering&Technology,Tianjin University2. China Automotive Technology&Research Center3. State Key Laboratory of Engines,Tianjin University

摘 要：In the purification process of automobile exhaust,existing water plays an important role as an oxidant,which converts CO and hydrocarbons（HCs） by the water-gas shift（WGS） and the steam reforming（SR） reactions,respectively,especially at high temperatures.Meanwhile it is major component of the exhaust which can affect significantly the thermal stability of the three-way catalyst.Activity experiments were carried out close to the real operation conditions（GHSV,concentration,etc.） with a Pd/Ce0.67Zr0.33O2 catalyst supplying information on the CO and C3H8 oxidation reactions in feedstream formed by different reactant combinations.The obtained results showed that the activity of the CO and C3H8 oxidation was promoted by the addition of steam due to the WGS and SR reactions.The WGS and SR reaction were competitive under oxygen-lean conditions.The kinetic analysis was considered for WGS and SR reactions.

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