微波水热法制备稀土元素铒掺杂TiO_2光催化剂及光催化活性

采用微波水热法和溶胶-凝胶法制备稀土元素Er掺杂TiO_2光催化剂TiO_2-Er,以甲基橙溶液为模拟污染物,在微波辐射-紫外光照(MW-UV)和太阳光照条件下,考察TiO_2-Er光催化剂的光催化降解活性。分别用N_2吸附-脱附、ICP-AES和PL光谱分析对TiO_2-Er光催化剂进行结构测试和表征。结果表明,Er掺杂能显著提高TiO_2光催化剂光催化活性,微波水热法制备的TiO_2-Er光催化剂具有较高的光催化活性;微波水热法和溶胶-凝胶法制备的TiO_2-Er光催化剂微波辐射-紫外光照50 min,甲基橙降解率分别为100%和98.5%,太阳光照4 h,甲基橙降解率分别为99.0%和97.5%。微波水热法具有晶化时间短和元素掺杂均匀的优点,制备的TiO_2-Er光催化剂具有形貌均匀、孔径较大、孔分布均匀和比表面积较大等特点,且Er掺杂能抑制光生e~-/h~+复合,使光生e~-/h~+的分离效率得到提高,有利于光催化活性的提高。

Preparation of Er doped TiO2 photocatalyst by microwave hydrothermal method and its photocatalytic activity

Erbium doped TiO2 photocatalysts were prepared by microwave hydrothermal method and sol-gel method.Using methyl orange as organic pollutant,the photocatalytic activities of TiO2-Er photocatalysts were investigated respectively under the irradiation of microwave-ultraviolet(MW-UV) and sun light.The structure of TiO2-Er photocatalysts were characterized by N2 adsorption-desorption,ICP-AES and PL spectral analysis.The results showed that Er doped could obviously increase the photocatalytic activity of catalyst and TiO2-Er photocatalyst prepared with microwave hydrothermal method had higher photocatalytic activity.The degradation rates of methyl orange on TiO2-Er prepared by two methods were 100% and 98.5% respectively under the condition of MW-UV irradiation for 50 min,while the degradation rate of methyl orange were 99.0% and 97.5% respectively under the sun light for 4 h.Because the microwave hydrothermal method had the advantages of short time of crystallization and the uniform of element doping and so on,TiO2-Er photocatalyst prepared by this method possessed the characteristics of uniform morphology,larger pore size,uniform pore size distribution and larger specific surface area.Er doped could inhibit recombination of photo-induced electrons and holes,and improve the separation efficiency of hole-electron pairs,causing the higher photocatalytic activity of TiO2-Er.