Arrays of titanium dioxide (TiO₂) nanotubes were prepared on commercially pure titanium (Ti) foils by anodic oxidation in a 0.5 M hydrofluoric acid (HF)-based electrolyte with multiwalled carbon nanotubes (MWCNTs) up to 0.035 g/l. The samples were annealed at 450°C for 1 h after anodic oxidation to form a crystalline anatase structure. The effect of MWCNT addition on the morphology and photocatalytic activity of the nanostructures was characterized by scanning electron microscopy, Raman spectroscopy, ultraviolet–visible diffuse reflectance spectroscopy, photoluminescence spectroscopy and methylene blue degradation tests. The results showed that MWCNTs were successfully incorporated into the titanium dioxide nanotube structure and significantly affected its photocatalytic activity. The best photocatalytic performance was achieved with the use of 0.025 g/l MWCNTs in the electrolyte composition. However, when the MWCNT content in the electrolyte increased, the electron–hole recombination rate and photon absorption ability of the structure deteriorated, resulting in a decreased photocatalytic activity.

中文翻译：

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碳纳米管掺入对TiO2纳米管光催化活性的影响

通过在 0.5 M 氢氟酸 (HF) 基电解质中进行阳极氧化，在商业纯钛 (Ti) 箔上制备二氧化钛 ( TiO ₂ ) 纳米管阵列，其中多壁碳纳米管 (MWCNT) 高达 0.035 g/l。阳极氧化后样品在450℃下退火1小时，形成结晶锐钛矿结构。通过扫描电子显微镜、拉曼光谱、紫外可见漫反射光谱、光致发光光谱和亚甲基蓝降解测试表征了MWCNT的添加对纳米结构形貌和光催化活性的影响。结果表明，多壁碳纳米管成功融入二氧化钛纳米管结构中，并显着影响其光催化活性。在电解质组合物中使用 0.025 g/l MWCNT 可获得最佳光催化性能。然而，当电解质中MWCNT含量增加时，结构的电子-空穴复合速率和光子吸收能力恶化，导致光催化活性下降。