Double Helix SPINDLE Module for 3-D Super-resolution Imaging of Nanoscale Plasmon-enhanced Photocatalysis
Abstract
Photocatalytic reactions are important for using light energy to drive chemical transformations, including destructing toxic chemicals. Optically excited surface plasmon (SP) can enhance catalytic reactions on semiconductor photocatalysts with supported plasmonic nanoparticles. This enhanced catalysis provides a potential way to more efficiently harvest solar energy directly to chemical energy, drive reactions at lower temperatures, and modify catalytic selectivity. Several mechanisms may operate for the catalytic enhancement, including the thermal effect and the energetic electron effect. Differentiating these mechanisms is essential for understanding the SP-induced catalytic enhancement and exploiting it for applications, but is often challenging experimentally, making new experimental methods desirable. In a project currently funded by ARO, we are developing novel methods to control plasmonic nanostructures and image catalytic reactions at high spatiotemporal resolution in operando, so as to quantify the kinetics and understand the mechanism of SP-enhanced catalysis on catalytic surfaces. Our main approach is single-molecule super-resolution fluorescence imaging of catalytic reactions on individual nanostructures down to nanometer precision, an approach pioneered by our group and supported by ARO. However, our current instrument could only achieve nanometer-precision mapping on the 2-dimensional (2-D) xy plane, whereas the information on the third z-dimension is inaccessible. This technical inadequacy limits our study to catalysts with mostly flat morphologies. As a consequence, catalysts with more complex 3-dimensional (3-D) morphologies cannot be sufficiently examined. The objective of this DURIP project is to acquire an add-on equipment module, ÒDouble Helix SPINDLE,Ó to our existing optical microscope to enable 3-D single-molecule super-resolution fluorescence imaging, with nanometer resolution in x, y, and z dimensions so as to expand our study to catalysts with complex 3-D morphologies. This objective, once achieved, should have the following significances as well as positive impacts on the Reactive Chemical System (RCS) program and the AROÕs mission: (1) it will provide a new capability (i.e., 3-D imaging) to interrogate SP-enhanced catalysis; (2) it will contribute fundamental knowledge about the mechanisms of SP-enhanced catalysis and about catalytic processes at solid-liquid interfaces, an important goal of the RCS program; (3) SP-enhanced catalysis provides a direct way to utilize solar energy to drive reactions; this would be particularly enabling for soldiers deployed in remote locations where conventional energy sources are scarce or limited; and (4) the SP-enhanced catalysis can be exploited for the development of effective catalysts for destroying chemical warfare agents (e.g., organophosphorus compounds) or other hazardous materials, which can protect soldiers in the battlefield.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Mar 20, 2019
- Source ID
- W911NF1910170
Entities
People
- Peng Chen
Organizations
- Army Contracting Command
- Cornell University
- United States Army