Cobalt-vanadium binary oxide type selective catalytic reduction supported catalyst for diesel engine

Abstract

The invention discloses a cobalt-vanadium binary oxide type selective catalytic reduction supported catalyst for a diesel engine. According to the catalyst, the cobalt-vanadium binary oxide is taken as a main active component, WO3 is taken as a cocatalyst, CeO2, ZrO2, gamma-Al2O3 and anatase type TiO2 are combined to form coating auxiliaries, and 400-mesh cordierite honeycomb ceramics are taken as a supported catalyst carrier. The preparation process of the cobalt-vanadium binary oxide type selective catalytic reduction supported catalyst comprises the following steps: determining the usage amounts of the catalyst raw materials, preparing a coating slurry precursor and a coating slurry, and applying the coating slurry. A urea solution or ammonia gas is taken as a reducing agent for the catalyst. According to the cobalt-vanadium binary oxide type selective catalytic reduction supported catalyst for the diesel engine, low-toxicity Co2O3 is adopted to take the place of high-toxicity V2O5, so that the damage caused by the catalyst is reduced and the low-temperature selective catalytic reduction (SCR) reaction catalytic activity of the catalyst is improved. Cerium oxide and zirconium oxide are added to the coating to enhance the oxygen storage capacity of the catalyst; the alumina sol is taken as a coating binder, so that the raw material cost and process difficulty of catalyst production are reduced.

Description

technical field [0001] The invention belongs to diesel engine tail gas purification technology, in particular to a catalyst used for automobile tail gas purification and a preparation method thereof. Background technique [0002] With the rapid growth of global motor vehicle production, automobile exhaust has become the nitrogen oxide (NO X ) is one of the most important sources. NOx is not only a toxic and irritating substance, but also a precursor of secondary ultrafine particles and acid rain, which seriously endangers the atmospheric environment and human health. As one of the main driving forces of motor vehicles, diesel engines not only have high specific NOx emissions, but also because the single engine power of diesel engines is generally higher than that of gasoline engines, the NOx emissions of diesel vehicles are much higher than those of gasoline vehicles. In addition, since the diesel engine adopts a lean-burn, oxygen-enriched combustion method, the exhaust ga...

AI Technical Summary

Problems solved by technology

However, V as the main active ingredient 2 o 5 It is a highly toxic substance, and its loss during the use of the SCR system will inevitably endanger environmental safety

At the same time, as one of the coating materials, TiO 2 The cost is high, and its own oxygen storage performance is not good, which is not conducive to the further improvement of the catalytic performance of the low-temperature SCR reaction of the supported catalyst

The characteristic of vanadium-based SCR catalyst is that it has good NOx purification performance after the exhaust temperature exceeds 280°C, but its low-temperature activity is not good, and it is difficult to adapt to the operation of diesel vehicles under the conditions of congested roads, slow speed, and low exhaust temperature.

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