| Summary: | Selective catalytic reduction (SCR) of NO<sub>x</sub> with NH<sub>3</sub> as the reductant has been proven an efficient and cost-effective technology to remove NO<sub>x</sub> pollutants in industries. Traditional SCR catalysts usually operate above 300 °C and suffer from intoxication and limited lifetime. Nano-catalysts are attractive for their high catalytic activities at reduced operating temperatures. We have recently developed a series of nitrogen-doped graphene-supported Mn-Ce oxides (MnCeO<sub>x</sub>/NG). The influences of reaction temperature, space velocity, mole ratio of NH<sub>3</sub>/NO and O<sub>2</sub> concentration on SCR de-nitration activity were assessed. The novel catalyst with optimal Mn/Ce ratio, at appropriate processing conditions, can achieve a NO conversion efficiency of 99.5% at a temperature of 180 °C, and 93.5% at 150 °C. The kinetics of the SCR reaction on this novel catalyst were also established, exhibiting first-order with respect to NO, zero-order to NH<sub>3</sub>, and nearly 0.5-order to O<sub>2</sub> at low temperatures. In the presence of sufficient O<sub>2</sub> content, the apparent activation energy of the NH<sub>3</sub>-SCR on MnCeO<sub>x</sub>/NG is 37.6 kJ/mol, which is promising for low-temperature applications.
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