SCR Catalysts

SCR catalytic substrate is mainly used in diesel engine exhaust system. SCR stands for selective catalytic reduction. Its principle is that under the action of a catalyst, the reducing agent NH3 reduces NO and NO2 to N2 at 290-400°C, and almost no NH3 oxidation reaction occurs.


According to the so-called SCR (Selective Catalytic Reduction ) process, the SCR catalysts are used to reduce nitrogen dioxide emissions. SCR specifies the process by which harmful nitrogen dioxide is selectively converted, that is, with a suitable catalyst as the target.

Working Principle of SCR Catalysts:

Exhaust gas from diesel engines usually contains excess oxygen (O2). In order to be able to reduce nitrogen dioxide under these conditions, a selective reducing agent is required, which converts the target nitrogen dioxide into nitrogen (N2) and water (H2O). A dilute solution of urea is used here as a reducing agent. In this case, urea is decomposed in the exhaust gas and forms an active ammonia reducing agent (NH3).

scr working principleApplication:

The SCR system is used in the field of private cars and commercial vehicles, and the technology is widely used to meet Euro VI or EPA 2010 emission standards. Many off-road diesel engines also use this technology. The SCR system can be used in a wide range of applications in the original equipment and retrofit markets.

Common Sizes of SCR Honeycomb Ceramic Substrate:

No. Section Shape Specification holes / square inch No. Section Shape Specification   holes / square inch
1 cylinder Ø143.8*76.2 400 10 cylinder Ø240*152.4 300
2 cylinder Ø143.8*101.6 400 11 cylinder Ø267*101.6 300
3 cylinder Ø143.8*152.4 400 12 cylinder Ø267*152.4 300
4 cylinder Ø170*101.6 300 13 cylinder Ø286*101.6 300
5 cylinder Ø190.5*101.6 300/400 14 cylinder Ø286*152.4 300
6 cylinder Ø190.5*52.4 300/400 15 cylinder Ø305*101.6 300
7 cylinder Ø228*101.6 300 16 cylinder Ø305*152.4 300
8 cylinder Ø228*152.4 300 17 cylinder Ø330*101.6 300
9 cylinder Ø240*101.6 300 18 cylinder Ø330*152.4 300