The Surface Plasmon Resonance (SPR) driven photocatalytic H₂ production upon visible light illumination (≥500 nm) was investigated on gold-loaded TiO₂ (Au–TiO₂). It has been clearly shown that the Au-SPR can directly lead to photocatalytic H₂ evolution under illumination (≥500 nm). However, there are still some open issues about the underlying mechanism for the SPR-driven photocatalytic H₂ production, especially the explanation of the resonance energy transfer (RET) theory and the direct electron transfer (DET) theory. In this contribution, by means of the EPR and laser flash photolysis spectroscopy, we clearly showed the signals for different species formed by trapped electrons and holes in TiO₂ upon visible light illumination (≥500 nm). However, the energy of the Au-SPR is insufficient to overcome the bandgap of TiO₂. The signals of the trapped electrons and holes originate from two distinct processes, rather than the simple electron–hole pair excitation. Results obtained by Laser Flash Photolysis spectroscopy evidenced that, due to the Au-SPR effect, Au NPs can inject electrons to the conduction band of TiO₂ and the Au-SPR can also initiate e⁻/h⁺ pair generation (interfacial charge transfer process) upon visible light illumination (≥500 nm). Moreover, the Density Functional Theory (DFT) calculation provided direct evidence that, due to the Au-SPR, new impurity energy levels occurred, thus further theoretically elaborating the proposed mechanisms.

中文翻译：

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对表面等离子共振 (SPR) 驱动的 Au-TiO2 光催化制氢的新见解†

_{在载金的 TiO 2} (Au-TiO ₂ )上研究了在可见光照射 (≥500 nm) 下表面等离子共振 (SPR) 驱动的光催化 H ₂产生。已经清楚地表明，Au-SPR 可以在光照（≥500 nm）下直接导致光催化 H _{2释放。然而，关于 SPR 驱动的光催化 H 2}生产的潜在机制仍然存在一些悬而未决的问题，特别是对共振能量转移（RET）理论和直接电子转移（DET）理论的解释。在这项贡献中，通过 EPR 和激光闪光光解光谱，我们清楚地显示了由 TiO 中捕获的电子和空穴形成的不同物种的信号₂在可见光照射下（≥500 nm）。然而，Au-SPR的能量不足以克服TiO ₂的带隙。被捕获的电子和空穴的信号源自两个不同的过程，而不是简单的电子-空穴对激发。激光闪光光解光谱的结果表明，由于Au-SPR效应，Au NPs可以将电子注入TiO ₂的导带，并且Au-SPR也可以引发e ^- /h ⁺在可见光照射（≥500 nm）下产生对（界面电荷转移过程）。此外，密度泛函理论 (DFT) 计算提供了直接证据，表明由于 Au-SPR，出现了新的杂质能级，从而在理论上进一步阐述了所提出的机制。