Facile and fast synthesis of novel Mn2CoO4@rGO catalysts for the NH3-SCR of NOx at low temperature

Abstract

Series of Mn2CoO4@reduced graphene oxide (Mn2CoO4@rGO) catalysts for NH3-SCR of NOx at low temperature were successfully prepared by fast and facile microwave irradiation method, during which the reduction of graphene oxide (GO) and the Mn2CoO4 nanosheets uprightly and regularly growing on the rGO layers occurred simultaneously. The activity of the Mn2CoO4@rGO catalyst exhibited a volcano-type tendency with an increase in loading amount of Mn2CoO4 and the 0.3 Mn2CoO4@rGO displayed optimal NOx conversion, excellent N2 selectivity and stability. Besides, SO2 poisoned catalyst could be regenerated by water-washing and restore to original level since that the uniform three-dimensional structure make water-washing particularly effective. The most important point to be noted is that for the 0.3 Mn2CoO4@rGO catalyst both catalytic activity and N2 selectivity are beyond 90% in 140–180 °C, which marvelously meets the demand of converting NOx to N2 as much as possible. Characterization results indicates that excellent catalytic performance of 0.3 Mn2CoO4@rGO may be mainly attributed to large specific surface area, abundant Lewis acid sites, and especially the special three-dimensional architectures of the catalyst.