Solvothermal Synthesis of Cerium-Doped Titania Nanostructured Materials Modified with Acetylacetone for Solar-Driven Photocatalysis

This study reports the preparation of nanostructured cerium-doped titanium dioxide photocatalysts containing different cerium concentrations by a modified sol-gel route involving the use of acetylacetone. The nanocrystalline powders had their structural, morphological, and optical properties characterized by X-ray diffraction, vibrational and Raman spectroscopy, thermogravimetric analysis, X-ray photoelectron spectroscopy, Brunauer, Emmett and Teller (BET) surface area analysis, scanning electron microscopy combined with energy dispersive X-ray spectroscopy, total reflection X-ray fluorescence, and diffuse reflectance spectroscopy. Cerium incorporation reduced the bandgap energy of the solids to values that allowed them to absorb visible light. Cerium presence improved the textural properties that are crucial for the catalytic process. The photocatalytic activities were evaluated through photodegradation experiments of methyl orange dye solution. The synthesis with acetylacetone as stabilizer provided nanostructured materials with higher Ce3+/Ce4+ ratio, which enhanced the photocatalytic activity. Smaller quantities of the doped photocatalysts afforded higher degradation rates than the rates reported in the literature.

本研究报道了采用以乙酰丙酮（acetylacetone）为稳定剂的改进型溶胶-凝胶（sol-gel）工艺，制备不同铈掺杂浓度的纳米结构铈掺杂二氧化钛光催化剂的方法。针对所制备的纳米晶粉体，研究人员通过X射线衍射（X-ray diffraction）、振动光谱与拉曼光谱（vibrational and Raman spectroscopy）、热重分析（thermogravimetric analysis）、X射线光电子能谱（X-ray photoelectron spectroscopy）、布鲁诺尔-埃米特-特勒（Brunauer, Emmett and Teller, BET）比表面积分析、结合能量色散X射线能谱的扫描电子显微镜、全反射X射线荧光光谱以及漫反射光谱（diffuse reflectance spectroscopy），对其结构、形貌与光学性能进行了表征。铈的掺杂将该固体的禁带宽度降至可吸收可见光的范围；同时改善了催化过程所需的关键织构性能。本研究通过甲基橙染料溶液的光降解实验，评估了材料的光催化活性。以乙酰丙酮为稳定剂的合成工艺所得纳米结构材料具有更高的三价铈/四价铈（Ce³+/Ce⁴+）比例，从而提升了其光催化活性。相较于已有文献报道的结果，使用更低剂量的该掺杂型光催化剂即可获得更高的降解速率。