Every high school chemistry student learns the definition of a catalyst, yet even the most sophisticated chemists lack a clear understanding of how catalyst surfaces work on a molecular level. Matthew Neurock, the Alice M. and Guy A. Wilson Professor of Chemical Engineering, is developing and applying quantum mechanical methods and computer simulations to understand the atomic features and molecular phenomena that govern catalysis.

“We are compiling a suite of tools that enable us to understand adsorbate-surface interactions and quantify the energetics of elementary reaction steps,” Neurock says. “This information is used to simulate the vast array of competing elementary surface reaction steps, follow the temporal surface structure and model material performance.”

Fuel Cells on a budget

One area in which Neurock’s expertise is critical is the development of fuel cells. With support from a Multi University Research Initiative (MURI) grant from the Army Research Office, he is part of a team developing better catalytic materials for polymer electrolyte membrane (PEM) fuel cells driven by methanol.

Currently, the catalysts of choice for anodes and cathodes in the direct methanol fuel cell are platinumbased alloys, but the military would like to reduce their cost and improve their durability. They have asked the MURI team to propose novel alloys that would decrease the amount of platinum or completely replace it, increase the catalytic activity at the anode and the cathode and prevent the loss of catalyst over time.

These same issues apply to hydrogen PEM fuel cells targeted for the automotive industry; any improvements to the catalysts for direct methanol will likely aid the hydrogen fuel cell.

“We can calculate the kinetics of each reaction at the quantum level and then move up to the molecular scale to describe how catalysis happens on the surface,” Neurock says. “With this information in hand, we can alter the alloy composition and surface structure to control the reaction to our specifications.”

The Three-metal Solution

Through modeling and simulation, Neurock has proposed a series of three-metal systems — currently being tested by industry — that provide desirable characteristics. Armed with a more exact knowledge of the sequence of methanol reactions, he and his colleagues are also exploring the use of other substances, such as hydrogen, formic acid and ethanol, as potential fuels for both portable and automotive PEM fuel cells.

Originally published in the fall 2006 issue of Explorations. Published with permission.