Electrocatalysts are critical to increase reaction rates and control selectivity in many electrochemical fuel production and consumption reactions. In the Jaramillo Group, we develop new electrocatalyst materials for processes including hydrogen evolution and oxidation, oxygen evolution and reduction, and carbon dioxide reduction. These reactions are necessary for electricity generation in hydrogen fuel cells, H2 production through water electrolysis, and CO2 conversion to create useful fuels and chemicals. Our approach is to understand the catalyst properties that control activity, selectivity, and stability by combining catalyst synthesis and electrochemical performance testing with physical and chemical characterization as well as computational and theoretical modeling performed by collaborators. Using these insights, we design new electrocatalyst materials with improved performance.

Hydrogen Evolution Reaction

The hydrogen evolution reaction (HER, 2 H+ + 2 e → H2) is the reduction half reaction in electrochemical water splitting. This reaction offers the potential to produce H2, a critical chemical reagent and potential clean-burning fuel, from renewable energy sources. Achieving high energetic efficiency for water splitting requires the use of a catalyst to minimize the overpotential necessary to drive the HER. Platinum is the best known catalyst for HER and requires very small overpotentials even at high reaction rates in acidic solutions. However, the scarcity and high cost of Pt limits its widespread technological use. We study the fundamental material properties that determine catalytic activity for the HER. Using these insights, we have developed several earth-abundant HER catalysts, including sulfide- and phosphide-based materials, with activities approaching that observed for platinum.

CO2 Reduction Reaction

Electrochemical reduction of CO2 has a potential of becoming a major contributor to sustainable production of fuels and chemicals through the use of renewable CO2 free energy sources. However, the development of an effective catalyst is vital, as there are currently no industrial scale operations that utilize this technology due to the low energetic efficiency. In our group, we focus on gaining fundamental understanding of the surface chemistry by tuning some of the key catalyst characteristics, such as the composition, the surface structure, and the morphology, as well as other factors, such as electrolyte composition and reaction conditions. By implementing the insights gained from our work, we aim to design effective catalysts that would allow for the industrialization of the technology.