Economical, Clean Liquid Fuels
Electric cars, geothermal heating, and wind and solar power generation can all reduce carbon emissions. But these technologies have important limits. Batteries, for example, due to their low energy density, are not practical to power long-haul aircraft and container ships, which will continue to burn liquid fuels for the foreseeable future.
However, there are alternatives to fossil-based liquid fuels. Udo Schwarz, PhD, is part of a team studying the process of combining carbon dioxide and hydrogen to produce methanol employing a catalyst; the methanol can then be converted to other liquid fuels as needed.
Water, split using electrochemical energy, provides the hydrogen.
“The vision is that you use ‘surplus’ renewable energy [to make methanol] when there’s too much sun or wind and you can’t use it all up,” said Schwarz, who is Professor of Mechanical Engineering and Materials Science and Professor of Chemical and Environmental Engineering. “Once you burn the fuel, you only generate as much CO2 as you took from the atmosphere before, so ideally, the entire process would be net zero.”
There are exciting developments taking place with the development of liquid fuels, with some shipping companies being early adopters of methanol as an alternative to diesel fuels. But costs remain high. The team is using advanced scanning probe microscopy to investigate how to best tune the adsorption properties of a process intermediary, carbon monoxide, onto a highly efficient cobalt-based molecular catalyst. Such knowledge is essential to minimize the energy input needed to drive the reaction, which is a stumbling block to making such conversion more cost-competitive.
Learning to optimize a cobalt catalyst for this reaction might also allow the development of other novel catalysts based on cheaper, more abundant metals, like iron. “The vision is you’ll find something you can upscale to be fairly economical,” Schwarz said. “If you need fuel, then, in theory, all you need is water and carbon dioxide.”
