NOx and CO abatement by applying catalysts with an active coating made of transition non-precious (CuO–Cr2O3, TiO2) and precious (Pt) metals

Abstract

In this study, the investigation of simultaneous removal of nitrogen oxides and carbon monoxide from gas emissions produced as a result of propane–butane gas combustion was performed. For this purpose, the special experimental prototype with catalysts of the honeycomb structure with an active layer synthesized by applying a plasma spray coating technique was used. During the present investigation, such active materials as precious metals (Pt) and also economically feasible materials such as copper–chromium oxide (CuO–Cr2O3) and titanium oxide (TiO2) were tested and compared. The mechanism of NOx and CO catalytic removal was described taking into account the NO and NO2 conversion. It was established that the initial CO concentration produced as a result of fuel combustion has a negligible impact on its removal efficiency while the initial CO/NOx ratio has a direct influence on the dependence of NOx removal efficiency on operating temperature. With increasing the CO/NOx ratio not only the NOx reduction efficiency can be increased but also the onset temperature of the catalytic conversion process can be lowered. The obtained results indicated that the efficiency of carbon monoxide and nitrogen oxides conversion with the use of tested transition metal oxides can achieve 95% and 80%, respectively.