Low-temperature SCR of NO over physical mixture of MnO₂ and metal-loaded activated carbon

Selective catalytic reduction (SCR) of NO with ammonia was carried out over the physical mixture of MnO₂ and K or Cu-loaded activated carbons (AC) at low temperature. Introduction of oxygen affected positively the reduction of NO. Metal-impregnated AC showed significantly enhanced catalytic activity. Without water, the mixed catalyst of MnO₂ and K-loaded AC exhibited the best activity in the reduction of NO at 120°C. On the contrary, the activities of all the catalysts were significantly diminished in the presence of water. The mixed catalyst of MnO₂ and Cu-loaded AC treated with nitric acid and heat (1 : 1, w/w) exhibited the better activity for the reduction of NO than each single catalyst in presence of water.