Model for Ceria Oxide System. Ceria atoms are yellow, oxygen atoms are blue, and the active oxygen at the defects are purple.

Catalysts, which accelerate chemical reactions, are valuable in many industries, from fuels to pharmaceuticals. Long-term research by government and academic scientists supported by the Office of Science has led to new understanding of catalytic phenomena, in particular the relationship between chemical structure and reactivity. For example, early work established two classes of heterogenous catalysts (which function by adsorbing molecules), based on whether chemical reactivity is, or is not, sensitive to surface structure. These studies showed that catalytic reactions once thought to be structurally insensitive actually took place on a dynamic surface. Research on the reactivity of hydrogen with catalysts—an issue in the world's largest-scale industrial processes, such as sulfur removal from crude oil-disproved the widely held belief that hydrogen molecules must dissociate into two atoms before undergoing reactions, and challenged the accepted notion that surface-bound (as opposed to embedded) hydrogen was the only reactive form. Other discoveries concerned the chemical behavior of organometallic complexes (combinations of organic and metallic species) that are used, for example, in plastics manufacturing.

Scientific Impact: Research on structure-reactivity relationships has increased understanding of both natural and synthetic processes. The discovery of nonclassical binding of molecular hydrogen created a new field of study that may overcome some of chemistry's greatest challenges, such as conversion of natural gas to more usable liquid fuels (methanol or gasoline).

Social Impact: A modern society's standard of living can be measured by its accomplishments in catalysis, because every manufacturing process and energy-generating technique starts with catalysis. Catalysts first introduced by investigators supported by the Office of Science revolutionized a process used to make about 100 billion pounds of plastics per year worldwide; this work is leading to catalysts that produce superior plastics with new properties.

Reference: C.E. Tripa and J.T. Yates, Jr. Nature, 398 (1999) 591.

URL: http://www.sc.doe.gov/production/bes/chm/Programs/programs.html

Technical Contact: Don Freeburn, Office of Basic Energy Sciences, 301-903-3156

Press Contact: Jeff Sherwood, DOE Office of Public Affairs, 202-586-5806

SC-Funding Office: Office of Basic Energy Sciences