Plasmon-Mediated Reduction of Aqueous Platinum Ions: The Competing Roles of Field Enhancement and Hot Charge Carriers,The Journal of Physical Chemistry C

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Plasmon-Mediated Reduction of Aqueous Platinum Ions: The Competing Roles of Field Enhancement and Hot Charge Carriers
The Journal of Physical Chemistry C ( IF 3.3 ) Pub Date : 2016-03-17 00:00:00 , DOI: 10.1021/acs.jpcc.6b00530
Nam Hoon Kim ₁ , Carl D. Meinhart ₂ , Martin Moskovits ₃

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Plasmonic nanosystems can enhance photochemical processes taking place in their neighborhood on account of several plasmonically mediated processes, among them: (i) the enhancement of the optical fields in the vicinity of the nanosystem and (ii) the intervention of energetic electrons and/or holes in the redox chemistry of nearby molecules pursuant to plasmon excitation and decay. We describe a series of experiments in which tetrachloroplatinate anions are reduced to zerovalent Pt at the surface of gold nanoparticles and nanoparticle assemblies. We demonstrate that the spatial pattern of deposited Pt cannot be understood in terms of enhanced fields alone but likely involves hot electrons whose momenta are initially aligned with the electric vector of the polarized light used to excite plasmons but become randomized on account of electron–electron interactions and scattering within the metallic nanoparticles before the electrons’ energy is substantially thermalized. These conclusions are supported by numerical computations of the local electromagnetic fields scattered by gold nanoparticles, using a finite element approach. SERS measurements, carried out concurrently with the photoreduction, suggest that PtO₂ is at least one of the oxidation products formed in the oxidation reaction(s) countervailing the above reduction reaction.

中文翻译：

等离子体介导的铂水溶液还原：场增强和热载流子的竞争作用

等离子体等离子系统可以通过几个等离子介导的过程来增强在其附近发生的光化学过程，其中包括：（i）增强纳米系统附近的光场，以及（ii）高能电子和/或空穴的介入根据等离激元激发和衰变，在附近分子的氧化还原化学中的作用。我们描述了一系列实验，其中四氯化铂阴离子在金纳米颗粒和纳米颗粒组件的表面还原为零价Pt。我们证明，仅凭增强场无法理解沉积Pt的空间格局，而可能涉及热电子，其动量最初与用于激发等离子体激元的偏振光的电矢量对准，但由于电子与电子的相互作用而变得随机化电子能量基本上被热之前，在金属纳米颗粒中的散射和散射。这些结论得到了使用有限元方法对金纳米颗粒散射的局部电磁场进行数值计算的支持。与光还原同时进行的SERS测量表明PtO 这些结论得到了使用有限元方法对金纳米颗粒散射的局部电磁场进行数值计算的支持。与光还原同时进行的SERS测量表明PtO 这些结论得到了使用有限元方法对金纳米颗粒散射的局部电磁场进行数值计算的支持。与光还原同时进行的SERS测量表明PtO_图2所示的反应产物是在与上述还原反应相反的氧化反应中形成的氧化产物中的至少一种。

更新日期：2016-03-17

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