新型(NH4)2Er5F17/TiO2复合可见光催化剂的制备及光催化活性研究

通过一步水热法制备了含稀土Er的(NH₄)₂Er₅F₁₇/TiO₂复合光催化剂，利用稀土元素f 电子的特征跃迁吸收将催化剂的光吸收范围拓展至可见光，通过罗丹明B（RB）染料模拟水中的污染物，对其进行光催化降解，并通过XRD、UV-vis、TEM、EDX-mapping、XPS、PL对催化剂样品进行了表征。结果表明，形成的稀土基化合物(NH₄)₂Er₅F₁₇粒径约为50nm，具有良好的六方型结晶形貌，实现了与商用P25 TiO₂的有效复合，稀土Er³⁺在可见光区522nm、487nm、654nm和800nm处出现的特征吸收峰拓展了复合光催化剂的可见光响应。对不同n(Er)/n(Ti)复合催化剂催化活性的评价表明，当n(Er)/n(Ti)=0.02时，由于(NH₄)₂Er₅F₁₇在TiO₂载体上均匀分散，有较强的光吸收，复合光催化剂的电子空穴复合率较低而表现出对RB最高的可见光催化降解活性。

Preparation and photocatalytic activity of a novel (NH4)2Er5F17/TiO2 composite visible light photocatalyst

(NH₄)₂Er₅F₁₇/TiO₂ composite photocatalysts have been synthesized via a one-pot hydrothermal route. The materials exhibited extended absorption in the visible light region due to f electron excitation absorption by the rare earth element Er. The photocatalytic activities were evaluated by degrading Rhodamine B (RhB) under visible light illumination and the structures of the composite photocatalysts were characterized by XRD, UV-vis, TEM, EDX-mapping, XPS, and PL techniques. The results indicate that the rare earth-based compound(NH₄)₂Er₅F₁₇ possesses a hexagonal crystal structure with a crystal size of about 50nm and can be effectively combined withTiO₂. The light response of(NH₄)₂Er₅F₁₇/TiO₂composite photocatalysts were broadened due to the characteristic absorption peaks of the rare earth Er³⁺ ion at 522nm, 487nm, 654nm and 800nm in the visible light region. The photocatalytic activity evaluation of the composite photocatalysts with different n(Er)/n(Ti) ratios showed that the sample with n(Er)/n(Ti)=0.02 has the highest photocatalytic activity in RhB degradation because of its uniform dispersion, strong light absorption and low electron-hole recombination rate. 