CAREER: Computational discovery of oxide-based photocatalysts to create fertilizer from air

Georgia Tech Research Corporation, Atlanta GA

Investigators

Abstract

Industrial agriculture enables the large-scale production of crops that support modern society, and agriculture relies heavily on nitrogen-based fertilizers produced from ammonia. Industrial ammonia synthesis is concentrated in about 50 large-scale plants around the world that collectively consume around 2% of the world's energy and are responsible for around 3% of global carbon emissions. The project will investigate alternative technology for producing fertilizers at agricultural sites by directly utilizing molecular nitrogen from the air, hydrogen from water, and energy from sunlight. Currently, the rate of ammonia production is far too low to enable the production of fertilizer from air. Thus, the research will focus on discovery of new catalyst technology capable of manufacturing ammonia from air and sunlight via a process known as photocatalytic ammonia synthesis. The resulting solar fertilizers would contribute to environmental sustainability and enhance national food security. The overall objective of the project is to improve the efficiency of solar fertilizer processes through catalyst discovery and reactor design. The strategy for catalyst discovery will involve computational simulations of the properties of the active site and reaction mechanism for nitrogen reduction on rutile metal oxides with p-block dopants. Insight from this model system will guide screening studies to identify promising new classes of oxide-based p-block compounds such as oxyborides and oxycarbides. Reactor design studies will also guide screening by establishing targets for materials properties such as efficiency and cost. Simple experiments will validate reactor models and establish a platform for testing predicted catalysts. The proposed work will advance knowledge in several ways. First, it will establish new strategies for the rational design of photocatalytic materials based on complex metal compound materials. Second, it will advance the computational models needed to analyze complex multi-step photocatalytic reactions. Third, it will use an innovative model that integrates student researchers, agricultural experts, and community stakeholders to assess the social and economic potential of solar fertilizer production. The culmination of these results will establish an exemplar for the design of multi-element photocatalyst materials for multi-step chemical reactions, and thereby advance the field of solar fertilizers. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.