Activation Energies of Plasmonic Catalysts
Activation Energies of Plasmonic Catalysts
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DOI：
10.1021/acs.nanolett.6b01373
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发表时间：
2016-05-01
期刊：
影响因子：
10.8
通讯作者：
Jain, Prashant K.
中科院分区：
文献类型：
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作者：
Kim, Youngsoo;Torres, Daniel Dumett;Jain, Prashant K.
催化反应的活化能不仅可以作为催化剂效率的度量，而且可以作为催化反应和非催化反应之间机理差异的潜在指标。然而，活化能在光催化领域的利用还很不足。我们详细表征了可见光激发对等离子体Au纳米粒子光催化电子转移反应活化焓的影响。我们发现在可见光激发下，Au纳米粒子催化电子转移反应的活化焓显著降低。激活焓的降低取决于激发波长、入射激光功率和空穴清除剂的强度。在这些结果的基础上，我们认为，活化焓降低是直接相关的光电化学势建立在稳态光激发下的Au纳米粒子，类似于电化学活化。在最佳光激发条件下，测得高达240 mV的电位。这些发现构成了对等离子体激发对过渡金属纳米颗粒催化的化学反应的机械作用和能量贡献的更精确的见解。
The activation energy of a catalytic reaction serves not only as a metric of the efficacy of a catalyst but also as a potential indicator of mechanistic differences between the catalytic and noncatalytic reaction. However, activation energies are quite underutilized in the field of photo catalysis. We characterize in detail the effect of visible light excitation on the activation enthalpy of an electron transfer reaction photocatalyzed by plasmonic Au nanoparticles. We find that in the presence of visible light photoexcitation, the activation enthalpy of the Au nanoparticle-catalyzed electron transfer reaction is significantly reduced. The reduction in the activation enthalpy depends on the excitation wavelength, the incident laser power, and the strength of a hole scavenger. On the basis of these results, we argue that the activation enthalpy reduction is directly related to the photoelectrochemical potential built-up on the Au nanoparticle under steady-state light excitation, analogous to electrochemical activation. Under optimum light excitation conditions, a potential as high as 240 mV is measured. The findings constitute more precise insights into the mechanistic role and energetic contribution of plasmonic excitation to chemical reactions catalyzed by transition metal nanoparticles.