本實驗在不同的退火溫度下成功合成了碳球@二氧化鈦的蛋黃殼奈米結構。這些獨特結構的奈米材料可用作光催化劑來降解新興的水污染物乙醯胺酚。通過紫外-可見吸收光譜討論了二氧化鈦中空結構和碳球@二氧化鈦蛋黃殼奈米結構的光學性質和能隙特性的變化。電子顯微鏡圖分析表明，隨著持溫時間和溫度的變化，碳奈米球（蛋黃）逐漸收縮到最終消失。此外，X光繞射圖譜證實，二氧化鈦為銳鈦礦相，其結晶度取決於退火溫度。光降解分析研究發現，當樣品在400度的持溫時間設置為0.5和1小時時，殘留有奈米碳球的樣品提高了光催化效率。XANES分析結果表明，當奈米碳球存在於二氧化鈦中空球中時，二氧化鈦奈米結構產生晶格畸變，並具有更多的氧空位 (Vo) 和低價鈦(Ti3+)。因此，可以推斷出二氧化鈦中空球和蛋黃殼奈米結構的光催化降解效率與未佔據的Ti 3d態的晶體場分裂和軌道對稱性密切相關。此外，根據 EXAFS 分析，當存在碳奈米球時，在八面體晶格的xy平面上觀察到氧空位，導致 z 軸縮短和結構無序增加。原位 XAS 測量表明，光降解背後的光催化機制是由於碳奈米球接收移動電子，這些電子可受紫外光與可見光激發而分離。O-Ti-O的軌道對稱性變化使得三價鈦離子費米面附近混成的Ti-3dxy和O-2pπ軌域導帶中的電子流出到碳奈米球中，產生更多的導帶空位。該過程會降低電子和空穴的複合速度，從而提高光催化效率。

Carbon@titania yolk-shell nanostructures were successfully synthesized at different annealing temperatures. These unique structure nanomaterials can be used as a photocatalyst to degrade the emerging water pollutant, acetaminophen (Paracetamol). The variations in optical properties and bandgap characteristics of TiO2 hollow structure and carbon@titania yolk-shell nanostructure are discussed by ultraviolet-visible absorption spectroscopy. An analysis of the HR-TEM images showed that the carbon nanospheres (yolk) are initially shrank and finally disappeared with a change in the holding time and temperature.Further, the XRD patterns confirmed that the TiO2 is in the anatase phase with different degrees of crystallinity depending on the annealing temperature.The photodegradation analysis studies have shown that the samples with residual carbon nanospheres have improved the photocatalytic efficiency, when the sample retention time at 400 degrees is set to 0.5 and 1 hour. XANES analysis results revealed that the TiO2 nanostructure generated lattice distortion, and has more oxygen vacancies (Vo) and low-valence titanium when carbon nanospheres exist in the TiO2 hollow shell. Therefore, it is deduced that the photocatalytic degradation efficiency of TiO2 hollow and yolk-shell nanostructure is strongly correlated to the crystal field splitting and orbital symmetry of the unoccupied Ti 3d state.
Besides, according to EXAFS analysis, when carbon nanospheres are present, the oxygen vacancy is observed on the xy-plane of the octahedral lattice, which leads to the shortening of the z-axis and the increase of structural disorder. In-situ XAS measurement indicates that the photocatalytic mechanism underlying the photodegradation is due to that the carbon nanospheres receive the mobile electrons that are separated by not only ultraviolet but visible light excitation. The orbital symmetry change of O-Ti-O makes the electrons in the hybridized Ti 3dxy and oxygen 2p orbital conduction band near the Fermi surface of the trivalent titanium ion, to flow out to the carbon nanospheres, and create more conduction band vacancies. This process would reduce the recombination speed of electrons and holes, thus increase the photocatalytic efficiency.

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