Storage of nitrous oxide (NOx)‎ in diesel engine exhaust gas using alumina-based catalysts : preparation, characterization, and testing

Abstract EN

This work investigated the nitrous oxide (NOx) storage process using alumina-based catalysts (K2O / Al2O3, CaO / Al2O3, and BaO / Al2O3).

The feed was a synthetic exhaust gas containing 1,000 ppm of nitrogen monoxide (NO), 1,000 ppm i-C4H10, and an 8 % O2 and N2 balance.

The catalyst was carried out at temperatures between 250–450 °C and a contact time of 20 minutes.

It was found that NOx was effectively adsorbed in the presence of oxygen.

The NOx storage capacity of K2O / Al2O3 was higher than that of BaO / Al2O3.

The NOx storage capacity for K2O / Al2O3 decreased with increasing temperature and achieved a maximum at 250°C.

Potassium loading higher than 15 % in the catalyst negatively affected the morphological properties.

The combination of Ba and K loading in the catalyst led to an improvement in the catalytic activity compared to its single metal catalysts.

As a conclusion, mixed metal oxide was a potential catalyst for de-NOx process in meeting the stringent diesel engine exhaust emissions regulations.

The catalysts were characterized by a number of techniques and measurements, such as X-ray diffraction (XRD), electron affinity (EA), a scanning electron microscope (SEM), Brunner-Emmett-Teller (BET) to measure surface area, and pore volume and pore size distribution assessments.