Wang Zixin, Wang Hui
Department of Chemistry and Biochemistry, University of South Carolina Columbia South Carolina 29208 USA
Nanoscale Adv. 2023 Aug 23;5(20):5435-5448. doi: 10.1039/d3na00498h. eCollection 2023 Oct 10.
Integration of plasmonic nanoantennas with catalytically active reactors in deliberately designed hybrid supra-nanostructures creates a dual-functional materials platform, based upon which precise modulation of catalytic reaction kinetics becomes accomplishable through optical excitations of plasmon resonances. Here, we have developed a multistep synthetic approach that enables us to assemble colloidal Au@C/Pt core@shell/satellite supra-nanostructures, in which the Au core functions as a light-harvesting plasmonic nanoantenna, the Pt satellites act as catalytically active reactors, and the C shell serves as a nanoscale dielectric spacer separating the reactors from the antenna, respectively. By adjusting several synthetic parameters, the size of the Au core, the thickness of the C shell, and the surface coverage of Pt satellites can all be tuned independently. Choosing Pt-catalyzed cascade oxidation of 3,3',5,5'-tetramethylbenzidine in an aerobic aqueous environment as a model reaction, we have systematically studied the detailed kinetic features of the catalytic reactions both in the dark and under visible light illumination over a broad range of reaction conditions, which sheds light on the interplay between plasmonic and catalytic effects in these antenna-reactor nanohybrids. The plasmonic antenna effect can be effectively harnessed to kinetically modulate multiple crucial steps during the cascade reactions, benefiting from plasmon-enhanced interband electronic transitions in the Pt satellites and plasmon-enhanced intramolecular electronic excitations in chromogenic intermediate species. In addition to the plasmonic antenna effect, photothermal transduction derived from plasmonic excitations can also provide significant contributions to the kinetic enhancements under visible light illumination. The knowledge gained from this work serves as important guiding principles for rational design and structural optimization of plasmonic antenna-reactor hybrid nanomaterials, endowing us with enhanced capabilities to kinetically modulate targeted catalytic/photocatalytic molecule-transforming processes through light illumination.
将等离子体纳米天线与具有催化活性的反应器集成到精心设计的混合超纳米结构中，创建了一个双功能材料平台，在此基础上，通过等离子体共振的光激发可以实现对催化反应动力学的精确调控。在这里，我们开发了一种多步合成方法，使我们能够组装胶体Au@C/Pt核@壳/卫星超纳米结构，其中Au核作为光捕获等离子体纳米天线，Pt卫星作为催化活性反应器，C壳作为将反应器与天线分开的纳米级介电间隔层。通过调整几个合成参数，可以独立调节Au核的尺寸、C壳的厚度和Pt卫星的表面覆盖率。选择在有氧水环境中Pt催化的3,3',5,5'-四甲基联苯胺的级联氧化作为模型反应，我们系统地研究了在广泛的反应条件下，黑暗中和可见光照射下催化反应的详细动力学特征，这揭示了这些天线-反应器纳米杂化物中等离子体和催化效应之间的相互作用。得益于Pt卫星中等离子体增强的带间电子跃迁和发色中间体物种中等离子体增强的分子内电子激发，可以有效地利用等离子体天线效应在动力学上调节级联反应中的多个关键步骤。除了等离子体天线效应外，等离子体激发产生的光热转换也可以对可见光照射下的动力学增强做出重要贡献。从这项工作中获得的知识为等离子体天线-反应器混合纳米材料的合理设计和结构优化提供了重要的指导原则，使我们能够通过光照在动力学上调节目标催化/光催化分子转化过程的能力得到增强。
