EFRI DCheM: Distributed solar energy harvesting for carbon-free ammonia synthesis

This EFRI Distributed Chemical Manufacturing project seeks to provide the scientific and technical foundations for producing fertilizer close to the farm and for the avoidance of the significant greenhouse gas footprint of the current industrial standard ammonia synthesis process. Small-scale distributed fertilizer manufacturing is vital for rural areas of the U.S. and for many other regions of the world where access to fertilizer is limited.

The solar energy-driven and carbon-free strategy of distributed, small-scale ammonia production provide a platform for new business models for agricultural communities. Distributed fertilizer manufacturing close to the farm offers two intertwined pathways for significant global impact: one toward decreasing the carbon emissions during production and transportation of fertilizer, and another toward engaging agricultural and industrial stakeholders and exploring the best methods and appropriate scales for providing cost-effective access to fertilizer in rural communities here in the U.S. as well as in low-income countries suffering from food insecurity.

The project’s aims are not to replace the existing industrial ammonia synthesis infrastructure. Instead, the goal is to cover part of the future increased demand for fertilizer by enabling a sustainable distributed fertilizer manufacturing process for select rural locations such as farms operated by Native

American Indian tribes on a scale where it makes logistical and economic sense.

Th fundamental research project pioneers the concept of photo-enhanced thermal catalysis, conducting photocatalytic reactions not in a liquid phase batch reactor at ambient temperature and pressure, as is the general practice, but in a continuous flow gas-solid reactor at moderate temperatures and relatively low pressures. As such, this work will lay the foundation for a fundamental understanding of the underlying physics and surface chemistry that leads to photo-enhanced ammonia formation rates.

Besides developing novel catalytic materials and catalyst architectures optimized for light interaction, the project also brings significant innovation to reactor design by distributing light uniformly within catalyst plates in a new type of photocatalytic reactor. Renewable energy-powered electrolysis of water provides the required process hydrogen and nitrogen is separated from the air and further converted into fertilizer, such as aqueous ammonia, carbamate, or urea.

The solar-spectrum-enhanced thermal catalysis research results, combined with the project’s community and curricular engagement approach, will advance scholarship on three fronts: (1) fundamental understanding of the physics of photo-enhanced nitrogen activation on catalytic surfaces; (2) design and modeling of an integrated system for renewable-hydrogen-based distributed ammonia synthesis and fertilizer production; and (3) prototyping, piloting and assessment of training modules to convey the innovations to stakeholders and move towards implementation.

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.