William Schneider. Source: Notre DameWilliam Schneider. Source: Notre Dame

University of Notre Dame researchers are focusing on developing a new method that synthesizes ammonia using renewable energy. The current process used to create ammonia is the Haber-Bosch process, which was developed in the early 90s. The Harber-Bosch relies on non-renewable sources and fossil fuels to operate and can only be used in large, centralized chemical plants, making it harmful to the environment. The newly developed method for creating ammonia aims to be more eco-friendly and accessible.

Their new process uses plasma and non-noble metal catalysts to create milder conditions than the Haber-Bosch method. Plasma’s energy excites nitrogen molecules, which then reacts more readily on the catalysts. The energy for the reaction comes from the plasma, not high heat and intense pressure, so the creation of ammonia with this method can happen on the small-scale, which has not happened before. The new process can be used with renewable energy sources and distributed ammonia production.

"Plasmas have been considered by many as a way to make ammonia that is not dependent on fossil fuels and had the potential to be applied in a less centralized way," said William Schneider, H. Clifford and Evelyn A. Brosey Professor of Engineering, an affiliated member of ND Energy and co-author of the study. "The real challenge has been to find the right combination of plasma and catalyst. By combining molecular models with results in the laboratory, we were able to focus in on combinations that had never been considered before."

"The goal of our work was to develop an alternative approach to making ammonia, but the insights that have come from this collaboration between our research groups can be applied to other difficult chemical processes, such as converting carbon dioxide into a less harmful and more useful product. As we continue studying plasma-ammonia synthesis, we will also consider how else plasma and catalysts could benefit other chemical transformations," said Hicks.

The paper on this study was published in Nature Catalysis. The study was funded by the Department of Energy.