Bi掺杂介孔CeO_2的制备及其可见光催化性能

Preparation of Bi-doped mesoporous cerium oxide with highly photocatalytic performance under visible light irradiation

以Ce(NO3)4为Ce源,介孔SiO2(KIT-6)为模板,采用硬模板法制备介孔CeO2(m-CeO2)。通过浸渍法合成Bi掺杂m-CeO2(m-CeO2/Bi)光催化剂。利用N2吸附-脱附、X线衍射仪(XRD)、透射电子显微镜(TEM)等手段对样品的物理化学特性进行表征。在可见光(λ>420 nm)条件下,以对氯苯酚(4-CP)为目标污染物,考察m-CeO2/Bi光催化剂的催化性能。结果表明:m-CeO2/Bi光催化剂具有完整的晶型和规则的孔道结构,有利于光生电子和空穴的分离,同时Bi的掺入降低了催化剂的带隙能,有效提高了可见光催化性能。2%Bi掺杂的m-CeO2/Bi光催化剂性能最佳,光照4 h可将4-CP降解91%以上,催化剂经多次循环使用后,其光催化活性基本保持不变。

Mesoporous cerium oxides were prepared by a hard templating method using mesoporous silica dioxide （KIT-6） as the hard template, cerium nitrate as the source of cerium. The m-CeO2/Bi photocata- lysts were synthysized by the wet impregnation method. The samples were characterized by N2 adsorption- desorption isothermal analysis, X-ray diffraction （XRD） and transmission electron microscopy （TEM）. The photodegradation activity of m-CeO2/Bi powders was evaluated by using 4-chlorophenol （4-CP） as pollutant targets under visible light irradiation （A 〉 420 nm）. Results demonstrated that the m-CeOJBi photocatalyst equipped with high crystallinity and continuous pore channels, which benefited for the elec- tron-hole pairs separation, doped Bi could reduce the bandgap of the m-CeO2 photoeatalyst, thus effective- ly improving the visible light photocatalytic properties. The photodegradation yield of 4-CP was beyond 91% under visible light irradiation for 4 h. The photocatalyst could be recycled by several times and with- out losing its photoeatalytie activity.