Abstract
Photoelectrochemical (PEC) CO2 reduction (PEC CO2R) is a prospective approach for utilizing solar energy to synthesize a variety of carbon-containing chemicals and fuels, the most valuable of which are multicarbon (C2+) products, such as ethylene and ethanol. While these products can be produced with high faradaic efficiency using Cu, this occurs over a relatively narrow potential range, which, in turn, imposes constraints on the design of a device for PEC CO2R. Herein, we used continuum-scale modeling to simulate the solar-to-C2+ (STC2+) efficiency of PEC CO2R devices fed with CO2-saturated, 0.1 M CsHCO3. We then explored how cell architecture and the use of single or dual photoelectrode(s) alters the optimal combination of photoelectrode bandgaps for high STC2+ efficiency. Ultimately, this work provides guidance for the co-design of the device architecture and photoelectrode bandgaps required to achieve high STC2+ efficiency. The insights gained are then used to identify systems that yield the highest amount of C2+ products throughout the day and year.
Funder
Foundation for the National Institutes of Health
Energy Frontier Research Centers
Directorate for Engineering
Publisher
The Electrochemical Society
Subject
Materials Chemistry,Electrochemistry,Surfaces, Coatings and Films,Condensed Matter Physics,Renewable Energy, Sustainability and the Environment,Electronic, Optical and Magnetic Materials