Effect of pretreatment method of activated carbon on the catalytic reduction of NO by carbon over CuO

The influence of pretreatment method of activated carbon (AC) made from coconut shell, on the NO reduction by AC over CuO was studied, in which AC was used as a reducing agent and pretreated by air oxidation or wet oxidation in the HNO3(N), H2O2(H), H2SO4(S) or H3PO4(P) aqueous solution. The results show that over the CuO catalyst, the reductive activity of air oxidized AC for NO increases with a rise of the air oxidation temperature of AC, and the order of the reductive activity of wet oxidized AC for NO is AC-H > AC-N > AC-S > AC-P. The surface chemical properties of these ACs were studied by XRD, TPD, Boehm titration and so on. The dispersion of CuO on AC can be improved by treating AC with the HNO3 or H2O2 aqueous solution. AC treated with H2O2 is an effective reducing agent for the reduction of NO over CuO, and the temperature of complete reduction of NO by AC-H is 270 °C, which is 120 °C lower than that by original AC. Both the high concentration of acidic oxygen groups and moderate amount of basic sites on AC-H help to increase the conversion of NO reduced by AC-H.