Lakhdar Rostom, Freyria Francesca S, Mousdis George A, Bonelli Barbara, Elghniji Kais
Laboratory of Materials Applications in Environment, Water and Energy LAMEEE (LAM3E), Faculty of Sciences of Gafsa, University of Gafsa, Sidi Ahmed Zarroug University Campus, Gafsa 2112, Tunisia.
Department of Applied Science and Technology and INSTM-Unit of Torino Politecnico, Corso Duca degli Arbuzzi 24, Torino I-10129, Italy.
J Phys Chem C Nanomater Interfaces. 2024 Aug 6;128(32):13445-13457. doi: 10.1021/acs.jpcc.4c03459. eCollection 2024 Aug 15.
A salicylic-acid (SA)-modified samarium-doped TiO complex (Sm-TiO/SA) was synthesized via a sol-gel method followed by impregnation. A Raman Fourier transform IR and X-ray photoelectron spectroscopic study showed that SA (as an electron donor) forms a surface complex on the Sm-TiO surface through its phenolic/carboxylic functional groups. In the Sm-TiO/SA complex, a ligand-to-metal charge transfer (LMCT) is active, inducing a marked red-shift in the absorption spectrum of TiO, which extends to 550-600 nm. The synergetic effect between the LMCT process and the luminescent properties of the lanthanide ions (Sm) is discussed and supported by the photoluminescence spectra. Further photocatalytic experiments (under sunlight) and the study of the effect of different scavengers show the presence of competitive reactions between de-ethylation and cleavage of Rhodamine B (RhB) during its degradation. With the Sm-TiO/SA complexes, the superoxide radical ion (O ) is the main active species responsible for the -de-ethylation pathway under sunlight irradiation. The cleavage of RhB by the hydroxyl radical (OH) appears, instead, to dominate with the Sm-TiO photocatalysts.
通过溶胶 - 凝胶法随后浸渍合成了水杨酸（SA）修饰的钐掺杂TiO复合物（Sm-TiO/SA）。拉曼傅里叶变换红外光谱和X射线光电子能谱研究表明，SA（作为电子供体）通过其酚羟基/羧基官能团在Sm-TiO表面形成表面复合物。在Sm-TiO/SA复合物中，配体到金属的电荷转移（LMCT）是活跃的，导致TiO吸收光谱出现明显的红移，延伸至550 - 600 nm。光致发光光谱讨论并支持了LMCT过程与镧系离子（Sm）发光特性之间的协同效应。进一步的光催化实验（在阳光下）以及不同清除剂效果的研究表明，罗丹明B（RhB）降解过程中存在脱乙基反应和裂解反应之间的竞争反应。对于Sm-TiO/SA复合物，超氧自由基离子（O ）是在阳光照射下负责脱乙基途径的主要活性物种。相反，在Sm-TiO光催化剂作用下，羟基自由基（OH）对RhB的裂解似乎占主导地位。
