The Etching of Al-Doped Co3O4 with NaOH to Enhance Ethyl Acetate Catalytic Degradation

In this work, a series of defective Co3O4 catalysts (Al@Co3O4−x, x = 4, 6, 8 mmol/L, representing the NaOH concentration) were prepared by Al doping and NaOH etching via hydrothermal method for ethyl acetate degradation. The results indicated that the Al@Co3O4-6 catalyst presented the optimal catalytic performance for ethyl acetate degradation (T90 = 207 °C). The results of many characterizations, such as X-ray diffraction (XRD), scanning electron microscope (SEM), Fourier transform infrared (FT-IR) spectra, Raman, and temperature-programmed H2 reduction (H2-TPR), etc., showed that the Al doping and NaOH etching induced the production of defects and oxygen vacancies in the catalyst, improved the surface area, boosted the low-temperature reducibility, and promoted the low-temperature oxygen species desorption, which enhanced ethyl acetate oxidation over Al@Co3O4-6. Importantly, the possible ethyl acetate degradation pathway was revealed by in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), in the sense that the adsorbed ethyl acetate was gradually oxidized to ethanol and acetaldehyde, acetic acid, formate, and finally to CO2 and H2O.