One-step hydrothermal synthesis of MnO_x-CeO₂/reduced graphene oxide composite aerogels for low temperature selective catalytic reduction of NO_x

In response to the problem of air pollution caused by nitrogen oxides (NO_x), we synthesized a three-dimensional (3D) MnO_x-CeO₂ nanoparticles/reduced graphene aerogel for low-temperature selective catalytic reduction (SCR) of NO_x with NH₃ by a facile one-step hydrothermal treatment. During the hydrothermal reaction, the graphene nanosheets and MnO_x-CeO₂ nanoparticles self-assembled into 3D interconnected networks, in which the nanoparticles MnO_x-CeO₂ with uniform size were densely anchored onto the graphene nanosheets. Besides, the MnO_x-CeO₂/reduced graphene oxide (RGA) exhibited unique properties such as high specific surface area, and numerous catalytically active sites in comparison with pure MnO_x-CeO₂ nanoparticles. Evidences have shown that the chemical bonding between MnO_x-CeO₂ and GO achieved high selective catalytic reduction efficiency. The MnO_x-CeO₂/RGA composites displayed highly enhanced catalytic activity in comparison to bare MnO_x-CeO₂ nanoparticles which achieved 99% NO_x conversion at 220 °C. This work provided a versatile approach to induce the combination of reduced graphene oxide sheets and other oxide nanoparticles, which opened up new avenues for the design and manufacture of catalysts used for low temperature SCR of NO_x with NH₃.