Low-temperature SCR catalyst for purification of diesel engine exhaust nitrogen oxides and preparation method thereof

Abstract

The invention relates to a low temperature form SCR (selective catalytic reduction) catalyst for purifying nitrogen oxide in diesel engine exhaust and a preparation method thereof. The adopted technical scheme is as follows: cordierite honeycomb ceramic is adopted as a carrier, the surface of the carrier is coated with a catalytic coating, and the catalytic coating comprises the following components in mass ratio: a base coating, an active component and a binder with the mass ratio of 8: (0.3-0.5): 1, wherein the base coating comprises the following components: titanium dioxide, tungsten trioxide and silicon dioxide with the content mass ratio of (8-9): (0.5-1): (0.5-1); the active component comprises the following components: ferric oxide and manganese oxide with the mass ratio of (1.7-3.3): (6.7-8.3); the binder is silicon dioxide or aluminium oxide. The preparation method comprises the following steps: sequentially preparing the base coating, the active component and mixed size; coating the honeycomb carrier with the mixed size, so as to enable the coating amount to reach 190-210 g / L. The preparation method provided by the invention is simple, and the prepared low temperature form SCR catalyst for purifying nitrogen oxide in diesel engine exhaust is good in activity and relatively good in ageing resistance.

Description

technical field [0001] The invention relates to a low-temperature SCR catalyst used for purifying nitrogen oxides in exhaust gas of diesel engines, and belongs to the technical field of catalyst synthesis and preparation. Background technique [0002] Nitrogen oxides (NO x ) is one of the main pollutants in the atmosphere, and it is one of the main factors leading to major environmental problems such as photochemical smog, acid rain, and ozone layer destruction, and is also a research hotspot in environmental pollution control. With the development of China's automobile industry, the nitrogen oxides emitted by motor vehicles are also increasing. Research shows that in 2010, my country's automobile NO x The emission volume of China is about 6 million tons, of which the exhaust emissions from heavy-duty diesel vehicles account for about 74%. Therefore, for diesel NO x It is particularly necessary to control emissions. [0003] Selective catalytic reduction (SCR, selective...

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to solve the existing technology for the treatment of diesel engine exhaust NO x The vanadium-based SCR catalyst has poor low-temperature activity and toxicity, and provides a low-temperature SCR catalyst for purifying nitrogen oxides in diesel engine exhaust and a preparation method thereof