Controlling Catalytic Selectivity Mediated by Stabilization of Reactive Intermediates in Small-Pore Environments: A Study of Mn/TiO2 in the NH3-SCR Reaction

Controlling selectivity in heterogeneous catalysis is essential for designing processes that minimize the production of undesired byproducts. For example, TiO 2 -supported manganese oxide, a promising material for catalyzing the selective reduction of NO with NH 3 at very low temperatures, is currently restricted by poor selectivity because of the production of unwanted N 2 O, which has a greenhouse gas potential 300 times higher than that of CO 2 . In this study, we located manganese oxides in microporous TiO 2 with small pores of molecular dimensions and found that this catalyst exhibited superior N 2 selectivity (more than 98% at 100–200 °C) as compared to that of conventional Mn/TiO 2 nanoparticles. The enhancement in N 2 selectivity was consistently observed regardless of the amount of Mn active sites, demonstrating that the confining void environment is able to affect the site-spec…