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

NH₃ selective catalytic reduction (NH₃-SCR) has been a common method for eliminating nitrogen oxides (NO_x) 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 NO_x 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.