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Size and Shape Effect of Metal Oxides on Hydrocarbon Selective Catalytic Reduction of Nitrogen Oxides

금속 산화물 촉매의 크기와 형태에 따른 질소산화물의 탄화수소 선택적 촉매환원 특성

Ihm, Tae-Heon;Jo, Jin-Oh;Hyun, Young Jin;Mok, Young Sun
임태헌;조진오;현영진;목영선

  • Received : 2015.07.09
  • Accepted : 2015.10.01
  • Published : 2015.10.30

Abstract

This work investigated the size and shape effect of ${\gamma}$-alumina-supported metal oxides on the hydrocarbon selective catalytic reduction of nitrogen oxides. Several metal oxides including Ag, Cu and Ru were used as the catalysts, and n-heptane as the reducing agent. For the Ag/${\gamma}$-alumina catalyst, the $NO_x$ reduction efficiency in the range of $250{\sim}400^{\circ}C$ increased as the size of Ag decreased (20 nm>50 nm>80 nm). The shape effect of metal oxides on the $NO_x$ reduction was examined with spherical- and wire-shape nanoparticles. Under identical condition, higher catalytic activity for $NO_x$ reduction was observed with Ag and Cu wires than with the spheres, while spherical- and wire-shape Ru exhibited similar $NO_x$ reduction efficiency to each other. Among the metal oxides examined, the best catalytic activity for $NO_x$ reduction was obtained with Ag wire, showing almost complete $NO_x$ removal at a temperature of $300^{\circ}C$. For Cu and Ru catalysts, considerable amount of NO was oxidized to $NO_2$, rather than reduced to $N_2$, leading to lower $NO_x$ reduction efficiency.

Keywords

nitrogen oxides;selective catalytic reduction;size effect;shape effect

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Acknowledgement

Supported by : 한국연구재단