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Effect of MnO2 Crystalline Structure on the Catalytic Oxidation of Formaldehyde
Huiqi Lin, Dong Chen, Haibo Liu, Xuehua Zou, Tianhu Chen
Laboratory for Nanomineralogy and Environmental Material, School of Resources and Environmental Engineering, Hefei University of Technology, Hefei 230009, China
- MnO2 with different crystalline structure were synthesized by hydrothermal method.
- Among the four MnO2 catalysts, γ-MnO2 has the best destruction and removal efficiency.
- Mechanism of catalytic oxidation of formaldehyde has been suggested.
Manganese oxides prove to be a promising catalyst for formaldehyde (HCHO) elimination in catalytic oxidation. In this study, MnO2 with different crystalline structure (α-MnO2, β-MnO2, γ-MnO2, and δ-MnO2) were synthesized by hydrothermal method to investigate their catalytic performances towards the abatement of formaldehyde. The prepared catalysts were characterized and analyzed by the X-ray diffraction (XRD), hydrogen-temperature programmed reduction (H2-TPR), BET specific surface area, X-ray photoelectron spectroscopy (XPS), and ammonia-temperature programmed desorption (NH3-TPD). In addition, the apparent activation energy was also calculated by using Arrhenius plots. Among the above four prepared catalysts, the γ-MnO2 has the best destruction and removal efficiency (DRE), which was approaching to 100% for HCHO at 155°C. The catalytic activity of γ-MnO2 is associated with abundant mesopores, higher reducibility of surface oxygen species, and more oxygen vacancies as compared to other types of crystalline MnO2.
MnO2; Catalytic oxidation; Formaldehyde; Surface oxygen; Temperature programmed reduction.