-Fe₂O₃-supported Co₃O₄ nanoparticles to construct highly active interfacial oxygen vacancies for ozone decomposition

Ozone pollution has become one of the most concerned environmental issue. Developing low-cost and efficient catalysts is a promising alternative for ozone decomposition. This work presents a creative strategy that using alpha-Fe2O3-supported Co3O4 nanoparticles for constructing interfacial oxygen vacancies (Vo) to remove ozone. The efficiency of Co3O4/alpha-Fe2O3 was superior to that of pure alpha-Fe2O3 by nearly two times for 200-ppm ozone removal after 6-h reaction at 25 degrees C, which is ascribed to the highly active interfacial Vo. X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy suggest that the Fe3+-Vo-Co2+ was formed when Co3O4 was loaded in alpha-Fe2O3. Furthermore, the density functional theory (DFT) calculations reveal the desorption and electron transfer ability of intermediate peroxide (O-2(2-)) on Fe3+-Vo-Co2+ are higher than the Vo from other regions. In situ diffuse reflectance Fourier transform (DRIFT) spectroscopy also demonstrate the higher conversion rate of O-2(2-) on Co3O4/alpha-Fe2O3. Base on the intermediates detected, we propose a recycle mechanism of interfacial Vo for ozone removal: O-2(2-) is quickly converted to O-2(2-) and transformed into O-2 on interfacial Vo. Moreover, O-2-temperature programmed desorption (TPD), H-2-temperature-programmed reduction (TPR), and electrochemical impedance spectroscopy (EIS) reveal that the oxygen mobility, reducibility, and conductivity of Co3O4/alpha-Fe2O3 are greatly superior to those of alpha-Fe2O3, which is contributed to the conversion of O-2(2-). Consequently, our proposed strategy effectively enhances the activity and stability of the bimetallic transition oxides for ozone decomposition.