Developing an understanding of how to use ammonia as a fuel
A new perspective article provides guidelines for designing new catalysts for the oxidation of ammonia.
(Illustration by Jeff London | Pacific Northwest National Laboratory)
What if your household cleaners or fertilizer could be used as a carbon-free fuel?
A perspective article in the Journal of the American Chemical Society by a team of Pacific Northwest National Laboratory (PNNL) researchers from the Center for Molecular Electrocatalysis (CME) discusses the fundamental science of ammonia oxidation needed to turn ammonia into a viable fuel.
Ammonia, NH3, is a carbon-free liquid with energy stored in its N-H bonds. Previous attempts to use ammonia as a combustion fuel have been stymied by ammonia’s release of hazardous nitrogen oxides, NOx, upon burning.
Fuel cells that rely on oxidation and reduction to convert chemical energy to electricity avoid generating the same harmful pollutants, but require specific knowledge of how each reaction step occurs to design improved catalysts.
Fuel cells use electrocatalysts, substances that speed up a reaction involving moving charges without being consumed, to run efficiently.
The article, also featured on the journal cover, details the energies involved with each individual step in ammonia oxidation and provides guidelines for developing new catalysts for these reactions. This group effort features intellectual contributions from postdocs Peter Dunn and Brian Cook, staff scientists Aaron Appel and Samantha Johnson, and Laboratory Fellow and CME Director Morris Bullock.
The perspective relies on expertise developed at PNNL, highlighted by its central role in the CME (a Basic Energy Sciences-funded Energy Frontiers Research Center), in the field of molecular electrocatalysis, combining electricity with catalysts to facilitate difficult reactions.
Electrocatalysts are often complex materials that can be challenging to modify or study in detail. Molecular catalysts offer the advantage of tunability and well-established techniques to deeply examine each step of a reaction.
Previous work in the CME has provided insights into electrocatalytic transformations of oxygen and hydrogen, examining key reactions for carbon-neutral energy.
The insights presented in the perspective will serve as the basis for future research in the CME and in the expanding ammonia oxidation community.