Abstract

Nanoheterostructures based on titanium dioxide synthesized by the sol–gel technique are studied. Microscopy, X-ray diffraction, optical spectroscopy, and electron-spin resonance techniques are used. All the investigated samples are characterized by a large specific surface area (~100 m² per 1 g substance). It is established that the main types of radicals in the obtained structures are N^•, Ti³⁺, Мо⁵⁺, V ⁴⁺, and W ⁵⁺, depending on the composition of the samples. It is shown that nanoheterostructures consisting of several metal oxides have a high photocatalytic activity in the visible spectral region and the ability to accumulate photogenerated charge carriers. As a result, catalytic reactions in the samples continue even after illumination is turned off. A correlation is found between the rate of photocatalysis, the absorption spectra in the visible region, and the concentration of radicals in the studied structures. The results can be used to develop energy-efficient catalytic devices based on nanoheterostructures consisting of titanium, molybdenum, tungsten, and vanadium nanooxides in various combinations which operate under periodic illumination in the visible spectral range.

中文翻译：

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基于二氧化钛的光累积纳米异质结构

摘要

研究了通过溶胶-凝胶技术合成的基于二氧化钛的纳米异质结构。使用了显微镜，X射线衍射，光谱学和电子自旋共振技术。所有研究的样品均具有较大的比表面积（每1克物质约100 m ²）。已确定所获得结构中自由基的主要类型为N ^•，Ti ³⁺，Мо5 ⁺，V  ⁴⁺和W  ⁵⁺，具体取决于样品的组成。结果表明，由几种金属氧化物组成的纳米异质结构在可见光谱区具有很高的光催化活性，并且具有积累光生电荷载流子的能力。结果，即使关闭照明，样品中的催化反应仍在继续。在光催化速率，可见光区域的吸收光谱和所研究结构中自由基的浓度之间发现相关性。该结果可用于开发基于纳米异质结构的节能催化装置，该纳米异质结构由钛，钼，钨和钒的纳米氧化物以各种组合组成，并在可见光谱范围内周期性照射下工作。