PME Distinguished Seminar Series - Harry A. Atwater

Advances in Electrochemical Carbon Dioxide Capture and Conversion using Sunlight

Over the next 10 years, scientists and engineers will need to make the science advances that enable new scalable technologies for i) direct capture of dilute CO2 at the gigaton scale and ii) CO2 reduction to fuels, chemicals, and materials, powered by renewable energy or directly by sunlight.  I will discuss the science and technology of a scalable energy-efficient route to direct ocean capture of CO2 via electrochemical pH swing, that takes advantage of the carbonate chemistry of dissolved inorganic carbon in oceanwater. Directly generating liquid solar fuels from sunlight, water, and carbon dioxide requires an understanding of the complex interplay of transferred electrons, protons, and reactants, to control product selectivity at semiconductor photocathode and electrode surfaces.  I will present two tandem reaction schemes to enable liquid solar fuel generation from CO2: i) a three-terminal tandem photoelectrode with two monolithically integrated but distinct catalytic centers operating at independent potentials and current densities to produce methanol by a cascaded reaction sequence, and ii) a tandem photoelectrochemical gas diffusion electrode/solar thermocatalytic cascade that employs ethylene, carbon monoxide and hydrogen as intermediates to yield multicarbon products (butene, hexene, and heavier hydrocarbons).