This paper proposes the surface functionalization with carboxymethyl-β-cyclodextrin (CMCD) of lanthanum-doped TiO₂ nanoparticles, to increase their photocatalytic activity for the degradation of organic molecules. CMCD has the capability to capture these compounds, so increasing their density on the catalyst surface and bringing them into close proximity to the hydroxyl radicals formed. Moreover, the doping with lanthanum can generate superficial defects that capture the formed electrons, so avoiding recombination, and can increase the density of –OH groups or water molecules attached to the surface of the catalyst, potentiating the formation of hydroxyl radicals. From the FT-IR, XPS, DTA and TGA characterizations, it is possible to verify the inclusion of the elements on the TiO₂ surface and to propose a mechanism responsible for this lanthanum and CMCD inclusion. The kinetics evaluations show an increase in the degradation rate constants after the inclusion of the organic and inorganic molecules, with 99% degradation of a contaminant after 25 minutes.

中文翻译：

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镧掺杂 TiO _2的羧甲基-β-环糊精功能化：表征和增强光催化活性

本文提出了用镧甲基掺杂的TiO ₂纳米粒子的羧甲基-β-环糊精（CMCD）进行表面功能化，以提高其对有机分子降解的光催化活性。CMCD具有捕获这些化合物的能力，因此可以增加它们在催化剂表面上的密度，并使它们与所形成的羟基自由基非常接近。此外，镧掺杂会产生表面缺陷，从而捕获形成的电子，从而避免了重组，并可以增加附着在催化剂表面的–OH基团或水分子的密度，从而增强了羟基自由基的形成。根据FT-IR，XPS，DTA和TGA表征，可以验证TiO _2中是否包含元素并提出一种机制来负责这种镧和CMCD的包容。动力学评估表明，加入有机和无机分子后降解速率常数增加，25分钟后污染物降解99％。