Influence of transition metal based SCR catalyst on the NOx emissions of diesel engine at low exhaust gas temperatures

In this experimental study, silver nitrate (AgNO3) – tetraamin palladium (II) nitrate solution (Pd(NO3)2·4NH3) – titanium dioxide (TiO2) based catalyst was synthesized with the impregnation method for hydrocarbon-selective catalytic reduction (HC-SCR) system. In this system, 2-propanol and different mixtures of 2-propanol and adBlue were used as reducing agents and the effect of the synthesized catalyst on NOx conversion efficiency was investigated. The structural and chemical properties of the catalysts were performed by Scanning Electron Microscope (SEM), X-Ray Diffractometer (XRD) and Brunauer-Emmett-Teller (BET) instruments. Experiments were conducted using the prepared catalyst in a temperature ranging from 170 °C to 300 °C at intervals of 10 °C, and 1 space velocity (SV) of 30000 h−1 at the SCR exhaust test performance system. The tests were also performed using 2 cylinders, V-type diesel engine with constant speed of 3000 rpm and at four different engine loads (1, 2, 3 and 4 kW). In conclusion, the highest NOx conversion rate recorded in the tests was 68.1% at 4 kW engine load, 100% 2-propanol spraying condition. In addition to this, it was demonstrated that 2-propanol has positive effect on NOx conversion rate in comparison with abBlue reductant.