Converting sunlight to clean fuels: The challenges of artificial photosynthesis and progress at the Conn Center

At the Renewable Energy Research & Education 2018 conference in Rajahmundry, India, scientists from the Conn Center for Renewable Energy Research presented educational lectures and research results from several key areas of renewable energy. Among the possible paths forward for a global sustainable energy future, the production of clean fuels through solar energy is a promising technology to store the intermittent energy of sunlight in a dense and portable form. Solar fuels, or artificial photosynthesis, is an approach that integrates light-absorbing semiconductors with electrocatalysts in an electrolyte to produce photogenerated charge-carriers capable of directly driving an electrochemical reaction to produce a chemical fuel. Key criteria for the development of an efficient solar fuels system include optimizing the semiconductor bandgaps and charge-collection properties for the electrochemical reaction, minimizing the anodic and cathodic activation overpotentials through highly active electrocatalysts, and ensuring a stable system that does not rapidly corrode under operation. Solar fuels research at the Conn Center strives to advance this technology and improve its practicality by working on key challenges in the areas of electrocatalysis, carbon-neutral liquid fuel production, photoelectrochemistry, and novel device design. A review of Conn Center progress in these areas is provided including acid-stable water oxidation catalysis, enhancing the selectivity for CO₂ reduction, novel light-driven systems, and a demonstration of solar hydrogen production from ambient humidity.