Keith Griffiths Associate Dean of Science (Academic) B.Sc., Liverpool University PhD., Liverpool University Office: Chemistry 123. Lab: Chemistry 009a Phone (Office): 519 661-2111 ext 84141
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Surface Science
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Awards:
• University Students Council Teaching Honour Roll
• Faculty of Science Award of Excellence in Undergraduate Teaching
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Current Research Programs:
Catalytic reactions applicable to automobile exhaust management
We study the complex chemistry taking place on the surface of the catalyst in an automobile exhaust system, but in the highly controlled environment of ultra-high vacuum. Our recent work has focused on such reactions as NOx + hydrocarbon (or alcohol) + oxygen on the surface of a single crystal of platinum. Because the reactions are taking place in an ultra-high vacuum environment, we can control the flux of several gases independently, as well as the platinum surface temperature. We use modern infrared spectroscopy as our primary surface probe along with thermal desorption, and Auger electron spectroscopy. We have been successful in elucidating the mechanism of several such reactions over a single crystal Pt surface (which has a well defined terrace-plus-step surface structure). We will be continuing and extending this work, including new surfaces such as silver and iridium, and also to including compounds of sulfur such as hydrogen sulfide and sulfur dioxide.
Reactions of acidic compounds on the surface of ice
A new project will tackle interesting and environmentally relevant reactions of acidic compounds on the surface of ice. Acidic compounds of chlorine (HCl, ClNO3) and of nitrogen (HNO2 and HNO3) are known to be in abundance in the stratosphere, and condense on ice particles during the dark winter months. It has been long established that these compounds eventually lead to ozone depletion through a complex gas phase reaction path. The chemistry and the detailed interaction of these molecules with the ice surface are less established and we can apply our expertise to this problem. We will grow controlled-thickness ice layers on an inert metal substrate. We will then deposit compound(s) of interest at the monolayer or submonolayer level and probe thermally and/or photon induced chemistry taking place on the surface of the ice. Our intent is to elucidate complex reaction mechanisms of great environmental significance, using model surfaces as catalysts, and modern surface analytical techniques.
Selected Publications:
Catalytic reduction of NO in the presence of benzene on a Pt(332) surface. Yuhai Hu and Keith Griffiths. Accepted for publication in Appl. Surf. Sci. July 12th 2007, doi: 10.1016/j.apsusc.2007.07.113.
NO-Methanol interaction on the surface of Pt(332). Yuhai Hu and Keith Griffiths. Surface Science, 601 (2007), 2467.
NO-C2H4 reactions on the surface of stepped Pt(332). Yuhai Hu and Keith Griffiths. Journal of Physical Chemistry C, 111 (2007), 9919.
CO-D2O coadlayers on Pt(111): Vibrational studies at low coverage. Yuhai Hu, Peter Norton, and Keith Griffiths. J. Vac. Sci. Technol. A, 25(4) (2007), 645.
