MnOx-TiO2 and Sn doped MnOx-TiO2 selective reduction catalysts prepared using MWCNTs as the pore template

Abstract

The stability of MnOx based low temperature SCR catalysts remained to be a serious issue. This report explored use of multi-walled carbon nanotubes (MWCNTs) network with uniform structure as a “rigid” pore template for synthesis of mesoporous MnOx-TiO2 SCR catalyst with high surface area and high stability. The results showed that MWCNT network imposed MnOx-TiO2 catalyst a mesoporous porosity with a narrow pore size distribution centered on ∼13.2nm and a surface area of 131.6m2g−1 stabilized at 500°C. The mesoporous structure was formed by interconnected nanoparticles, comprised of crystallized rutile TiO2 core surrounded by amorphous MnOx, with an average diameter of ∼8nm. The catalyst exhibited an excellent low temperature SCR activity and selectivity as well as high resistance to deactivation and poison by H2O and SO2. SnO2 modification led to degradation of catalytic performance in low temperature (60–180°C) side, but improvement at high temperature side (240–360°C), especially at high gas velocity, which can be attributed to change in structure, reactivity of MnOx and surface acidity induced by SnO2 addition.