Effect of Co Doping on Magnetic and CO-SCR Properties of γ-Fe2O3

Magnetic bayberry-like γ- x CoFe 2 O 3 microspheres catalysts with different mole ratios (Co/Fe = 0, 1, 3, 5, 7, 9%) are synthesized by a solvothermal method followed by calcination. Then, a series of characterizations are carried out using Raman spectroscopy, X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), H 2 temperature-programmed reduction (TPR), vibrating sample magnetometry (VSM), X-ray photoelectron spectroscopy (XPS), and in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). Also, as the results indicate that with increasing Co doping amount, the microspheres shrink first and then expand, which obviously affect the specific surface area and activity; samples’ catalytic performance is improved by doping an appropriate amount of cobalt, and 5Co–Fe shows the optimum activity with the largest surface area. Moreover, in-situ DRIFTS result shows that the introduction of Co promotes the formation of decomposable monodentate nitrates rather than chelate bidentate nitrates and improve samples’ magnetic properties, which promote more NO adsorbed on catalyst surface to form chelate nitrate species, so that enhanced the activity.