Graphene aerogel loaded with CeO2 as a catalyst for selective catalytic reduction of NOx with NH3 at low temperature

Abstract

NH3 selective catalytic reduction (NH3-SCR) has been a common method for eliminating nitrogen oxides (NOx) from the flue gas. The low-temperature denitrification has sparked widespread concern. Here, a CeO2/graphene aerogel (CeO2/GA) catalyst material was synthesized by a one-step hydrothermal method using a three-dimensional (3-D) porous graphene aerogel structure as a carrier for NH3-SCR at low-temperature. The presence of nanoparticle CeO2 inhibited agglomeration between graphene sheets, while the graphene aerogel as a carrier produced a porous structure and improved nanoparticle dispersal. The specific surface area of composite catalyst material was 178.68 m2/g. Catalysts with efficient charge transfer and abundant chemisorbed oxygen promoted redox reactions, more acidic sites were essential to improving catalytic activity. At 270 °C, the NOx conversion (94.9%) of this catalyst was 2.9 times higher than that of pure CeO2 and it demonstrated good N2 selectivity and catalytic stability.