The US Department of Energy (DOE) plans to provide up to $100 million over five years for research on artificial photosynthesis for the production of fuels from sunlight. (DE-FOA-0002254) The funding will support the establishment of one large or possibly two smaller DOE Energy Innovation Hubs: integrated multidisciplinary, multi-institutional research teams aimed at accelerating the fundamental scientific breakthroughs needed to enable solar fuel production.

While several approaches could potentially enable fuel production using sunlight as the only energy input, the new FOA focuses solely on artificial photosynthesis approaches: the direct use of sunlight, water, and abundant feedstocks for liquid fuel production.

Sunlight is our most basic energy source, and the ability to generate fuels directly from sunlight has the potential to transform our energy economy and vastly enhance US energy security.

—Under Secretary for Science Paul Dabbar

Plants use photosynthesis to convert energy from the sun into energy-rich chemical fuels using water and carbon dioxide. The goal of the research is to develop an artificial photosynthesis system that, like natural photosynthesis, would generate usable fuels directly from sunlight, carbon dioxide, and water. However, significant scientific barriers remain to the development of such a system, requiring new discoveries and fundamental breakthroughs.

The Department’s planned investment in the Fuels from Sunlight Hub program represents a continuing large-scale commitment of US scientific and technological resources to this competitive and promising area of investigation.

Proposed research is expected to build on the capabilities and accomplishments developed to date by the solar fuels research community, including work by the DOE Office of Science-supported Joint Center for Artificial Photosynthesis, Energy Frontier Research Centers, and core research programs.

Applications are asked to focus on research priorities identified by the Roundtable on Liquid Solar Fuels held in August 2019 by the Office of Basic Energy Sciences within DOE’s Office of Science. These priorities include:

• Understand the mechanisms that underpin constituent durability and performance. A current impediment to producing solar fuels is the limited lifetime of components. Significant opportunities exist to design, discover, and develop highly performing and durable components, including robust light absorbers with sufficient photovoltages; efficient, stable catalysts with high selectivity; and tailored materials such as membranes and electrolytes to control transport and permeability. A detailed understanding of the thermodynamics, kinetics, and mechanisms of degradation will enable predictive science for durability at the molecular, material, and component levels. New science will also advance strategies to circumvent or counteract processes that reduce component lifetime and performance.

• Control the catalyst microenvironment to promote selective and efficient fuel production. High selectivity and high activity in the light-driven production of energy-rich fuels present considerable challenges because of the complexity of chemically reducing CO₂ and N₂ as well as oxidizing H₂O. Advances require molecular-level understanding and control of the microenvironment around catalytic sites to direct reactions for key bond-making and bond-breaking steps. Research is needed to probe and control the interactions of catalysts with supports, light absorbers, electrolytes, and other components. It is also critical to understand how the microenvironment can mediate the transport of reactants, products, electrons, protons, and inhibitors to direct reaction pathways determining efficiency, selectivity, and degradation.

• Bridge the time and length scales of light excitation and chemical transformations. Most approaches to solar fuels generation decouple light absorption and chemical transformations. Significant opportunities exist to capitalize on the direct coupling of light-driven phenomena and chemical processes to enhance overall system performance. Exploiting light–matter interactions could open up new mechanisms to enable selectivity or efficiency that outperform conventional electrochemical reactions or utilize more of the solar spectrum. Fundamental research can realize advantages unique to light-driven fuels generation such as strong electronic coupling or light-induced structural changes.

• Tailor interactions of complex phenomena to achieve integrated multicomponent systems. Integration of individual molecular and material components presents challenges for generating solar fuels because individual elements may not perform the way they do in integrated systems. Fundamental research is needed to provide a mechanistic understanding of how individual multiscale processes interact and affect the function of integrated components. The resulting knowledge of how integration impacts performance, including durability, will guide the development of predictive models and enable the co-design of components for efficient, selective, and durable systems.

Applications are expected to take the form of multi-institutional proposals submitted by a single lead institution. Eligible lead and partner institutions include universities, nonprofits, DOE national laboratories, and other federal laboratories and agencies.

Total planned funding will be up to $100 million for awards beginning in Fiscal Year 2020 and up to five years in duration, with outyear funding contingent on congressional appropriations. Selections will be made based on peer review and may result in the establishment of one or two DOE Energy Innovation Hubs, depending on the scope of the selected proposals.