Low-temperature (NO + O2) adsorption performance of alkaline earth metal-doped C-FDU-15

To improve the removal capacity of NO + O 2 effectively, the alkaline earth metal-doped order mesoporous carbon (A-C-FDU-15(0.001) (A = Mg, Ca, Sr and Ba)) and Mg-C-FDU-15( x ) ( x  = 0.001−0.003) samples were prepared, and their physicochemical and NO + O 2 adsorption properties were determined by means of various techniques. The results show that the sequence in (NO + O 2 ) adsorption performance was as follows: Mg-C-FDU-15(0.001) (93.2 mg/g) > Ca-C-FDU-15(0.001) (82.2 mg/g) > Sr-C-FDU-15(0.001) (76.1 mg/g) > Ba-C-FDU-15(0.001) (72.9 mg/g) > C-FDU-15 (67.1 mg/g). Among all of the A-C-FDU-15(0.001) samples, Mg-C-FDU-15(0.001) possessed the highest (NO + O 2 ) adsorption capacity (106.2 mg/g). The species of alkaline earth metals and basic sites were important factors determining the adsorption of NO + O 2 on the A-C-FDU-15( x ) samples, and (NO + O 2 ) adsorption on the samples was mainly chemical adsorption. Combined with the results of (NO + O 2 )-temperature-programmed desorption ((NO + O 2 )-TPD) and in situ diffused reflectance infrared Fourier transform spectroscopy  (DRIFTS) characterization, we deduced that there were two main pathways of (NO + O 2 ) adsorption: one was first the conversion of NO and O 2 to NO 2 and then part of NO 2 was converted to NO 2 − and NO 3 − ; and the other was the direct oxidation of NO to NO 2 − and NO 3 − .