Influence of thermal treatment on the catalytic activity of Cu-loaded carbons in NO reduction with NH3 and regeneration of the thermally deactivated catalysts

The activity of carbon impregnated with Cu(NO3)2 in selective catalytic reduction (SCR) of NO with NH3 was examined at temperatures as low as 110–200 °C. An mineral-free carbon was employed as the base catalyst in the present work. The activity of the carbon was significantly enhanced upon the impregnation. The temperature employed in the thermal treatment following the impregnation is found to be crucial in optimizing the performance of the carbon catalyst. For thermal treatment temperatures lower than 350 °C, increasing the temperature would result in the decomposition of the residual nitrates and thus the increase of the activity. With further increase of the temperature, the activity decreased with the temperature, and this has been attributed to the aggregation of Cu upon thermal treatment. HNO3 treatment, which is capable of dissolving as well as re-dispersing the Cu aggregates, was found to fully regenerate the high-temperature treated carbon. The present study has demonstrated that the degree of Cu dispersion dominantly affected the activity of the Cu-loaded carbon, while the population of oxygen functional groups only gave a minor contribution to activity enhancement.