This award is supported by the Major Research Instrumentation and the Chemistry Research Instrumentation programs. The University of Central Florida is acquiring an X-ray photoelectron spectrometer (XPS) with ambient temperature capabilities to support Professor William Kaden and colleagues Sudipta Seal, Laurene Tetard, Xiaofeng Feng and Fudong Liu. This spectrometer operates at near ambient pressure unlike a conventional XPS which studies samples in a high vacuum. This enables characterization of materials involving all three phases of matter (solid, liquid, gas) in pressures as high as several tenths of an atmosphere. This capability greatly expands the classes of materials which can be investigated. An example is a project to improve a catalyst surface employed in hydrogenation reactions used to convert a feedstock into a more valuable product. Basically, XPS spectra are produced by irradiating the specimen with X-rays with sufficient energy to eject electrons. The kinetic energy of the electrons is measured. This provides information on the binding energy of the electron. These data can be related to the chemical elements in the sample and effects from their bonding environment. Such experiments assist characterization of the surface of the materials under study and can lead to improvement in their properties. The instrument is employed in research projects undertaken by undergraduate and graduate students preparing them for the modern workplace. It is incorporated into several programs in place to train and recruit underrepresented students.
The research enabled is directed at investigating gas-solid, liquid-solid, and gas-liquid interfaces under environmental conditions relevant for characterizations in situ (in the same place the phenomenon is occurring without isolating it from other systems or altering the original conditions of the test). The XPS is employed to dynamically identify surface interactions in heterogeneously catalyzed reactions as they occur commonly referred to as operando conditions. The instrumentation is used to characterize liquid-gas interfaces to help understand wet-chemical processes on resultant catalytic properties. In addition, it aids in the characterization of liquid-solid interfaces under varied conditions. The spectrometer is also utilized to investigate delicate biological samples which otherwise would be destroyed if the most common XPS technique that employs ultrahigh vacuum is used.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.