Abstract
Keywords:
SBA-15, de-NOx, HC-SCR
Abstract
Our recent research works on the selective catalytic reduction (SCR) of diesel engine NOx by hydrocarbons over Pt loaded mesoporous support (SBA-15) catalyst were reviewed. The reaction mechanism of the SCR of NOx by C3H6 over Pt/SBA-15 was studied using in situ DRIFTS. As reported previously, the bands at 1565 and 1656 cm-1 can be assigned to ν(NO2) and ν(ONO) of the surface organic nitro and nitrile compounds on the surface, was found on the surface of Pt/SBA-15 during the SCR of NOx by in situ DRIFTS. Based on this, a mechanism of the NOx reduction was proposed, which can successfully explain the high efficiency of the NOx reduction by C3H6 over Pt/SBA-15. The use of higher Pt loadings leads to enhanced activity at lower temperatures. But activity of Pt(3wt%)/SBA-15 and Pt(5wt%)/SBA-15 make little difference. The Pt(3wt%)/SBA-15 showed a higher NOx conversion than Pt(1wt%)/SBA- 15, especially at temperatures ranging from 150 to 250 ℃. De-NOx activity showed that the average NOx conversion was greater than 80% in the diesel engine exhaust temperature range of 150–250 ℃ using our catalytic converter with C3H6 as reductant, which represents a leap from the Euro III standard to the Euro Ⅳ standard for NOx emission control in diesel engines.