Studies have shown that the excitation of plasmon resonances on nanostructured materials can drive catalytic processes. Plasmon resonances can be tuned across the solar spectrum, thus offering intriguing possibilities for their application in plasmonic catalysis. Previous work carried out by our group has indicated that nanostructures with tight junctions can create direct current (DC) electric fields. These fields arise from an optical rectification of the plasmon resonance on the plasmonic surface, and our group has shown that these fields modulate photocatalytic activity. This work looks to shed further light on the impact that optically rectified fields can have on catalytic reactions. Cyclic voltammetry shows that the electrochemical reduction and oxidation potentials of a 2 mM CuSO₄ solution occur at ∼100 mV lower overpotential on an optically excited Ag nanodendrite electrode. Stark spectroscopy of the nitriles absorbed to these surfaces indicate photo-associated changes in the surface potential across the Ag nanodendrites. Localized areas evince photo-induced changes in the surface potential upwards of 300 mV. These results provide evidence of optically rectified fields altering the electrochemical reactivity on plasmonic surfaces and suggest that optimizing this nonlinear phenomenon may improve plasmonic photocatalysts.

中文翻译：

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光学整流场对等离子体电催化的影响

研究表明，在纳米结构材料上激发等离子体激元共振可以驱动催化过程。可以在整个太阳光谱范围内调节等离子体共振，从而为将其应用于等离子体激元催化提供了有趣的可能性。我们小组先前所做的工作表明，具有紧密结的纳米结构可以产生直流（DC）电场。这些场是由等离激元表面上的等离振子共振的光学整流引起的，我们的小组表明这些场调节了光催化活性。这项工作旨在进一步阐明光学整流场对催化反应的影响。循环伏安法表明2 mM CuSO ₄的电化学还原和氧化电位固溶在光学激发的Ag纳米树枝状电极上以低约100 mV的超电势发生。吸收到这些表面的腈的鲜明光谱表明，银纳米树突上的表面电势与光相关。局部区域显示出光诱导的表面电势变化高达300 mV。这些结果提供了光学整流场改变等离激元表面上的电化学反应性的证据，并表明优化这种非线性现象可以改善等离激元光催化剂。