Harrison Research Group

Catalysis is an essential technology supporting our way of life and contributes towards roughly 1/3 of the material GDP of the US economy. Since the beginning of the 20^th Century, the catalytic transformation of nitrogen on nanoscale, potassium promoted, iron catalysts to ammonia, and ultimately fertilizer, has profoundly changed the human condition and currently supports an additional 2.4 billion people beyond what the Earth could otherwise sustain. In the 21^st Century, the catalytic challenge will be to facilitate a rapid transition from a petroleum-based energy and chemical economy to a more generalized one based on natural gas, hydrogen, coal, biomass, and solar energy (photochemistry). Energy efficient chemical transformations, environmental protection, and green chemistry will continue to rely heavily on catalysis. Most industrially viable catalysis takes place on the surfaces of transition metal nanocrystallites dispersed on oxide supports. Our research focuses on understanding gas-surface reactions on simplified scientific model surfaces, namely, on single crystal surfaces. Important recent progress has been the development of quantitative models for (i) the C-H bond activation of CH₄ on Ni surfaces that is at the heart of natural gas reforming on Ni nanocatalysts that yields the industrial supply of H₂, and (ii) the chemical vapor deposition of Si on Si (100) by SiH₄ that is central to Si homoepitaxy in microelectronics manufacturing. Current activities focus on exploring the thermal and photochemical reaction dynamics of catalytically important and energy-related small molecules, such as H₂, CO₂, CH₄, alkanes, and alcohols on transition metal surfaces. Our research typically employs ultrahigh vacuum surface analytical techniques (e.g., TPD, AES, XPS, RAIRS, STM, LEED) as well as some more specialized laser techniques (SFG, TOF) and/or microcanonical unimolecular rate theory. Our goal is to characterize the transition states of important catalytic reactions and to develop an improved understanding of how to design efficient & selective thermal and photochemically driven catalysts.