Synthesis of Fibrous Micro-nano Hierarchical Porous Cerium Dioxide Materials by the Impregnation and Thermal Decomposition Method and Its Enhanced Photocatalytic Activity

Abstract

Fibrous micro-nano hierarchical porous cerium dioxide materials were prepared from oriental paperbush flower stems by impregnation and thermal decomposition methods. Thermogravimetric analyzer (TG, DSC), field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), transmission electron microscopy (TEM), N2 adsorption-desorption isothermals, temperature-programmed reduction (TPR), and UV-Vis spectrophotometer were used to characterize the thermal decomposition behavior, microstructure and photocatalytic properties of fibrous micro-nano hierarchical porous cerium dioxide materials. The results proved that the achieved products retained a fibrous morphology similar to oriental paperbush flower stems with the original biotemplate in material completely removed. The average diameter of CeO2 particles on the surface of the material is about 9 nm, and the large specific surface area is around 55.6 m2/g. UV-Vis absorption spectra showed that the fibrous micro-nano hierarchical porous cerium dioxide materials have high light absorption capacity and can respond to simulated sunlight. The effects of initial dye concentration, catalyst concentration, pH value, cycle number, and irradiation time on the photocatalytic activity of fibrous micro-nano hierarchical porous cerium dioxide materials for the photo-degradation of methylene blue under simulated solar irradiation were systematically studied. A reasonable photocatalytic mechanism is proposed based on the experimental results and theoretical analysis. This strategy can be extended to synthesize other broad bandgap semiconductor oxides with high photocatalytic activity for the photo-degradation of organic dyes under simulated solar irradiation.