Controlling Visible-Light Photodegradation of Organics on TiO2 Thin Films
The research goal of this project is to understand and control the individual reaction steps of organic air pollutants on doped TiO2 thin film catalysts in visible-light photodegradation reactions.
The PI approaches the photoreaction mechanism directly on the catalyst surface and at the molecular level at which the reaction operates. In situ scanning tunneling microscopy, coupled with Raman spectroscopy, will be used to analyze what happens to reactant adsorbates at certain surface sites in visible-light photoreactions. A femtosecond laser quantum control technique will be utilized to selectively break bonds in adsorbed molecules and to enable new reactions that are normally not accessible.
This research plan addresses fundamental questions that are essential for the rational design of catalysts that efficiently carry out the photo-oxidation of organic pollutants. Gaining molecular-level insight into photoexcited reaction mechanisms will impact a wide range of oxide-based photocatalytic applications. The manipulation of surface reactions provides a new form of selectivity in addition to the usual variation of temperature, pressure, and catalysts in chemical reactions.
Tip-Enhanced Raman Sensing on Semiconductor Catalysts
The research objective of this project is to advance molecular-level chemical identification of molecules on non-traditional Raman scattering materials for heterogeneous catalysis using a combination of the most advanced Raman spectroscopies. The team approach the Raman signal enhancement from both the fundamental understanding and the technological development points of view. STM provides a detailed molecular-scale local structural characterization of the scattering media (oxide-molecule complexes). A gold or silver STM tip will be used as an optical nanoantenna to investigate the physics of surface plasmon resonances (SPRs). The atomic spatial resolution provided by the STM combines with the chemical information provided by the Raman spectrometer. The insights from single molecules uses to understand the ensembles. Nonlinear optical properties of these materials will be used to guide the design of the oxide nanostructures for a new generation of sensors with enhanced capabilities.
Zhenrong Zhang Assistant Professor Department of Physics Baylor UniversityOne Bear Place #97316, Waco, TX 76798 Phone: (254) 710-2419 Email: Zhenrong_zhang@baylor.edu