NiBO (B = Mn or Co) catalysts for NH-SCR of NO at low-temperature in microwave field

Microwave-assisted selective catalytic reduction of nitrogen oxides (NO) was investigated over Ni-based metal oxides. The NiMnO and NiCoO catalysts were synthesized by the co-precipitation method and their activities were evaluated as potential candidate catalysts for low-temperature NH-SCR in a microwave field. The physicochemical properties and structures of the catalysts were characterized by X-ray diffraction (XRD), Scanning electron microscope (SEM), N-physisorption, NO adsorption-desorption in the microwave field, H-temperature programmed reduction (H-TPR) and NH-temperature programmed desorption (NH-TPD). The results verified that microwave radiation reduced the reaction temperature required for NH-SCR compared to conventional heating, which needed less energy. For the NiMnO catalyst, the catalytic efficiency exceeded 90% at 70 °C and reached 96.8% at 110 °C in the microwave field. Meanwhile, the NiMnO also exhibited excellent low-temperature NH-SCR reaction performance under conventional heating conditions, which is due to the high BET specific surface area, more suitable redox property, good NO adsorption-desorption in the microwave field and rich acidic sites. [Figure not available: see fulltext.].