March 8, 2007 --Ian Harrison and his colleagues in the chemistry department are tackling some of the most complex and important issues facing our world today by relying on some of the first lessons you ever learned in Chemistry 101.
The issues relate to sustainable energy. At a time when researchers are desperately seeking practical, plentiful and environmentally sound solutions to the world’s precarious energy situation, Harrison is trying to make those solutions faster and more efficient.
One of the most promising solutions,many feel, lies in hydrogen. “There’s a lot of interest in a possible hydrogen economy,” says Harrison. “But hydrogen is not by itself an alternative energy. It’s an energy carrier.” Hydrogen can be used as a chemical in a fuel cell, Harrison explains, “and produce just water and electricity. Terrific. That’s its upside.”
The downside lies in figuring out the best and most efficient way to acquire it. “Hydrogen is only as clean as the process by which you produce it. You don’t mine hydrogen; you can’t put a straw in the ground and get it like oil. You have to manufacture it.” Today the most effective way of generating hydrogen is through a process called steam reforming of natural gas. “Natural gas is mostly methane, CH4. Four hydrogen to one carbon is a good ratio, compared to other hydrocarbons or coal. If we mix it with water over nickel nanocatalysts, we can get four hydrogen molecules and just one of carbon dioxide. That turns out to be the most economical way to make hydrogen right now. And we’ve got a lot of methane around that could last us a good long time.”
And now, a blast from your academic past … Chemistry 101 and catalysis. “Whenever you want to make a chemical reaction,” Harrison says,“you have to energetically climb a hill to the transition state and then fall down the far side into the valley of the products.” He puts it in terms locals can appreciate. “It’s like going from Charlottesville to Staunton. You’ve got to go over the mountain. In fact, one of the first railway tunnels was through Afton Mountain. Basically a catalyst does that. Instead of having to go all the way over the mountain and come down the other side, you just dig a tunnel or otherwise engineer a lower energy pass.”
Catalysis for methane and other natural-gas-related alternative energy sources takes place on metal nanoparticles. By researching and studying aspects of the energy path necessary to convert these substances to useable energy, Harrison and his fellow researchers can piece together and predict reactive probabilities and help create shortcuts that may produce product more efficiently.
“This goes to the idea that we could start designing the nanoscale sequence of events, the dance of the molecules as they attempt to get over their mountain pass. We hope to choreograph that ballet a little better and influence the outcome.” Improving catalysts can play a role in creating not only more product but also in avoiding unwanted byproducts.
“I think some of the best catalysis practitioners in the world are right here,” he says, citing award-winning colleagues including Matthew Neurock, Bob Davis and John Yates as examples. “By leveraging such talent in a timely way, U.Va. could move to the forefront of catalysis research and help to move a sustainable energy future closer to reality.”
For Harrison, and so many engaged in the sustainability discussion, the issue extends far beyond facts, figures and equations. “There is a realenergy cost associated with having a good life,” he says. “Frankly, one of our biggest issues as a world is how much energy does it take to have a fulfilling life and can we justify our lifestyle when so many people are worse off, with no prospect, given the limited supply of fossil fuels, to ever get where we are. I feel we face a moral imperative to technologically lower our energy requirement so we can live sustainably. Only then can more of the world achieve a good life and the planet be preserved for future generations.”
Written by John Kelly, a freelance writer in Charlottesville.