Presto! Harnessing the sun to make fertilizer

Published: April 21, 2016
Assistant Professor Gordana Dukovic

Here’s a new recipe that might be good for the planet: Add sunlight to a particular nitrogen molecule and out comes ammonia, the main ingredient of fertilizer used around the world.

The eco-friendly method of producing ammonia is described in a new study led by the Department of Energy’s National Renewable Energy Laboratory in Golden and involving CU-Boulder. The researchers hope the discovery may help enhance global agricultural activities while decreasing the dependence of farmers on fossil fuels, says CU-Boulder Assistant Professor Gordana Dukovic, a study co-author. 

An important piece of the study was showing that nanocrystals of the compound cadmium sulfide can be used to harvest light. The light then energizes electrons enough to trigger the transition of the molecule dinitrogen (N2) into ammonia, explains Dukovic of the chemistry and biochemistry department.

“By integrating nanoscience and biochemistry, we have created a new, more sustainable method for this age-old reaction,” says Dukovic, who received a prestigious Sloan Research Fellowship in 2014 and who was named a National Science Foundation CAREER Award winner in 2012.

“Using light harvesting to drive difficult catalytic reactions has the potential to create new, more efficient chemical and fuel production technologies,” says NREL Research Scientist Katherine Brown, also a study co-author.

The new research is expected to inspire alternative concepts for meeting the demand for ammonia as a fertilizer, but in a more energy efficient and sustainable manner with a lower impact on the environment than current commercial processes, Dukovic explains. 

The study, which appears in Science, was led by NREL Research Scientist Paul King and also included researchers from Utah State University and Montana State University. In addition to Dukovic, other study co-authors include former CU-Boulder doctoral student Molly Wilker, now a faculty member at Luther College in Iowa, and current CU-Boulder doctoral student Hayden Hamby.