PhD Candidate Wins First Prize for Spectroscopic and Computational Study

Tao Chen, a PhD candidate from the Chemical Engineering & Materials Science Department at Stevens Institute of Technology (Hoboken, New Jersey), has won the first prize and a cash award for his research presentation at the annual symposium of the Catalysis Society of Metropolitan New York. Chen's winning presentation was titled “Spectroscopic and computational study of BPE adsorption on Ag/SiO2 as a function of silver oxidation and adsorbate coverage.” He is co-advised in his research by Stevens professors, Simon Podkolzin and Henry Du.

In Tao’s project, monodispersed silver nanoparticles with a diameter of about 50 nanometers supported on silica were synthesized using a colloidal solution. The extent of silver oxidation was varied with a time-controlled exposure to ozone and monitored with X-ray photoelectron spectroscopic measurements. Vibrational spectra were collected using surface-enhanced Raman spectroscopy. Adsorption geometries and vibrational modes were analyzed with quantum chemical calculations using density functional theory. This closely integrated experimental and theoretical study for the first time identified at the molecular level the adsorption modes and energetics of an organic probe molecule trans-1,2-bis(4-pyridyl)ethylene (BPE) on silver nanoparticles. In addition, effects of the adsorbate coverage and the extent of silver oxidation were evaluated. This understanding will help scientists to choose optimal conditions for running chemical reactions with catalytic silver nanoparticles and also to improve sensors that use similar nanoparticles as spectroscopic detectors.

The symposium was held on March 14, 2012 at the ExxonMobil Corporate Research in Annandale, NJ and was attended by more than 130 participants. Students and postdoctoral researchers participated in a poster competition with 30 poster presentations from universities in New York, New Jersey, Pennsylvania, and Delaware.