Unexpected Room-Temperature Selective Catalytic Reduction of NOx with NH3 over Metal-Free Carbon-Based Catalysts

Abstract

Catalysts operating at low temperatures are imperative for the denitrification of flue gases from various non-electric industries. Current catalysts typically exhibit significant activity for the selective catalytic reduction of NO_x with NH₃ (NH₃–SCR) at temperatures above 100 °C. Here, we observed for the first time remarkable room-temperature NH₃–SCR activity on the surface of carbon-based catalysts. The oxidation of NO to NO₂ by surface C–O–C groups at room temperature serves as a key initial step, triggering a fast SCR reaction. The C–OH groups, as active sites, directly participate in the elementary reaction pathways of the SCR through an H migration process, significantly reducing the energy barrier of the rate-determining step to below 1 eV, thereby enabling fast SCR to occur at room temperature. The room-temperature SCR and its novel reaction mechanism reported in this study would inevitably expand the research boundaries of NO_x abatement.