Using a combination of first-principles modelling, X-ray absorption spectroscopy, and diffuse reflectance spectroscopy measurements, we explore the properties of Ag₅-modified TiO₂ surfaces. A general electron polarization phenomenon associated with surface polarons on TiO₂ has been revealed theoretically and confirmed experimentally. First, the Ag₅ cluster donates an electron to TiO₂, leading to the formation of polaronic Ti³⁺ 3d¹ states on the rutile TiO₂(110) surface. The analysis of polarization effects in the nearby electronic structure accompanying the polaron formation is confirmed with X-ray absorption spectroscopy measurements at the Ti K-edge of TiO₂ nanoparticles. Next, the UV-Vis optical absorption spectrum of the polaronic state is also computationally modelled and an enlargement of the polaron wavefunction is predicted. Moreover, we find an overall improvement of the UV-Vis optical response of the material through diffuse reflectance spectroscopy measurements. Finally, we predict that charge-transfer processes at the Ag₅–TiO₂ interface triggered by solar photons might allow for a photoinduced activation of CO₂ by sunlight.

中文翻译：

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探索Ag5-TiO2界面的特性：稳定的表面极化子形成，UV-Vis光学响应和CO2光活化

结合第一原理建模，X射线吸收光谱和漫反射光谱测量，我们探索了Ag ₅修饰的TiO ₂表面的特性。理论上已经揭示了与TiO ₂上的表面极化子有关的一般电子极化现象，并通过实验进行了证实。首先，Ag ₅团簇将电子提供给TiO ₂，导致在金红石TiO ₂上形成极化子Ti ³⁺ 3d ¹态（110）表面。通过在TiO ₂纳米粒子的Ti K边缘的X射线吸收光谱测量，证实了伴随极化子形成的附近电子结构中极化效应的分析。接下来，还对极化子态的UV-Vis光吸收光谱进行了建模，并预测了极化子波函数的扩大。此外，我们发现通过漫反射光谱测量可以整体改善材料的UV-Vis光学响应。最后，我们预测，由太阳光子触发的Ag ₅ -TiO ₂界面处的电荷转移过程可能允许太阳光对CO ₂的光诱导活化。