Plasmonic Nanorattles as Next‐Generation Catalysts for Surface Plasmon Resonance‐Mediated Oxidations Promoted by Activated Oxygen

Abstract

Nanorattles, comprised of a nanosphere inside a nanoshell, were employed as the next generation of plasmonic catalysts for oxidations promoted by activated O2 . After investigating how the presence of a nanosphere inside a nanoshell affected the electric-field enhancements in the nanorattle relative to a nanoshell and a nanosphere, the SPR-mediated oxidation of p-aminothiophenol (PATP) functionalized at their surface was investigated to benchmark how these different electric-field intensities affected the performances of Au@AgAu nanorattles, AgAu nanoshells and Au nanoparticles having similar sizes. The high performance of the nanorattles enabled the visible-light driven synthesis of azobenzene from aniline under ambient conditions. As the nanorattles allow the formation of electromagnetic hot spots without relying on the uncontrolled aggregation of nanostructures, it enables their application as catalysts in liquid phase under mild conditions using visible light as the main energy input.

Addressing the Effects of Size‐dependent Absorption, Scattering, and Near‐field Enhancements in Plasmonic Catalysis

“…It can be anticipated that higher E‐field enhancements (as a result of stronger LSPR excitation) may lead to improved performances in LSPR‐mediated transformations ,. For example, near‐field at the metal‐adsorbate interface can increase the rates of photoexcitation of metal‐adsorbate bonds .…”

“…It is noteworthy that oxidation reactions play a pivotal role in a variety of industrial processes and synthetic routes ,. In this context, the activation of molecular oxygen (O 2 ) at the catalyst surface via LSPR excitation has been shown to represent a promising alternative to achieve high activities under green conditions ,…”

“…It allows the utilization of metal nanoparticles (NPs), such as gold (Au) and silver (Ag), as catalysts and visible light as an eco‐friendly and abundant energy input to drive chemical reactions ,,. As the LSPR excitation in Ag and Au NPs is strongly dependent on size, shape,, structure, composition,, and the dielectric constant of the environment, a systematic understanding of how these parameters govern LSPR‐mediated catalytic processes is imperative for the design of catalysts with desired performances.…”

Isolated Platinum Atoms Stabilized by Amorphous Tungstenic Acid: Metal–Support Interaction for Synergistic Oxygen Activation

“…The molecular oxygen can be activated via two main routes: 1) charge transfer, for example, the molecular oxygen accepts the hot electrons or photoexcited electrons and forms the superoxide; 2) energy transfer, for example, the triplet oxygen can transform into active singlet oxygen by receiving the external energy . The activation of molecular oxygen usually depends on certain chemical media or catalyst, for example, metal complex, metal oxides with oxygen vacancies, plasmonic metals, and semiconductors, and so forth. To date, due to the barriers in thermodynamics or dynamics, it is still a challenge to achieve highly efficient activation of molecular oxygen.…”

Nanoscale Surface Redox Chemistry Triggered by Plasmon‐Generated Hot Carriers

“…However, because reactants are usually directly absorbed on the metal surface, the substrate could also catalyze the reaction, via different pathways. For example, in the presence of O 2 , the widely studied coupling reaction of pATP on silver is thermodynamically favored and most likely triggered by adsorbed oxygen rather than by hot electrons . One way to minimize the effect of the metal–molecule interaction is by introducing a dielectric spacer layer between the metal and the adsorbate.…”