An Integrated Plasmonic Approach to the Design of Multifunctional Catalytic Materials
Abstract
We propose an integrated plasmonics approach to the development of innovative highly selective and multifunctional catalytic materials. In this work, visible-light-initiated, plasmon-mediated metal nanoparticle synthesis will be coupled with kinetic studies of hot electron-driven photocatalysis of partial hydrogenation reactions on the synthesized materials. Both nanoparticle synthesis and photocatalytic studies will be informed by modeling of plasmonic properties using Finite Difference Time Domain (FDTD) methods. A major goal of the proposed research is to provide greater insight into the complex mechanisms of plasmon-mediated reduction processes, both in terms of metal ion reduction during nanoparticle synthesis and with respect to heterogenous partial hydrogenation reactions. In addition, this work aims to use plasmon-driven reactions to achieve product selectivity that is unobtainable with thermal methods alone, both in nanoparticle synthesis and in heterogeneous catalysis. The metal nanoparticle synthesis approach to be employed is known as "plasmon-mediated synthesis." In this method, visible light excitation is used to drive metal ion reduction, leading to nanoparticle growth that is tunable using excitation wavelength and intensity. This process relies on the generation of energetic charge carriers---electrons and holes-through excitation of the localized surface plasmon resonance (LSPR) of small metal seeds. The versatility of the proposed light-responsive, plasmon-mediated synthetic approach for independently tailoring the optical and structural properties (such as shape, composition, and defect structure) of monometallic and multi-component nanocatalysts makes it an ideal system for defining structure-function relationships in plasmon-mediated catalysis, which will drive next-generation catalyst development. In addition, the proposed work aims to extend the boundaries of the plasmonic approach to (1) the generation of light-responsive reconfigurable silver nanostructures and (2) the synthesis of hybrid bimetallic nanomaterials composed of plasmonic and non-plasmonic metals using visible light excitation. Synthesized nanoparticles will be fully characterized using a range of techniques, including scanning electron microscopy, transmission electron microscopy, and energy dispersive x-ray, spectroscopy. The kinetics of nanoparticle growth will be analyzed using inductively coupled plasma atomic emission spectroscopy. In addition to challenges in nanoparticle synthesis, the mechanisms of direct plasmon-driven catalysis on metal nanoparticles, particularly those with well-defined shapes, have just begun to be understood. Many opportunities exist for using plasmonic photochemical; conversions to achieve catalytic selectivity that is unattainable using traditional, thermally-driven catalysis. Systematic studies of the plasmon-mediated partial hydrogenation of unsaturated aldehydes on nanoparticle catalysts with different shapes, defect structures, and compositions will be carried out under gas phase reaction conditions. However, this approach is translatable to solution phase catalysis as well. Particular emphasis will be placed on understanding plasmon-driven photocatalytic processes at interfaces, such as (1) defects in nonometallic materials and (2) interfaces between plasmonic and weakly plasmonic materials in hybrid nanostructures. The ultimate goal of the proposed work is to establish design principles which enable the light-mediated generation of a range of multifunctional, reconfigurable, and photocatalytically active nanomaterials with tunable selectivity.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Feb 14, 2019
- Source ID
- W911NF1810156
Entities
People
- Michelle L Personick
Organizations
- Army Contracting Command
- United States Army
- Wesleyan University