Fully Integrated Stand-Alone Device for Gas-Phase CO2 Reduction Using Sunlight: Proof of Concept

Abstract

The conversion of CO2 to fuels can be a promising pathway to reduce the carbon intensity of the economy, if the energy required for its conversion is supplied from renewable sources. We showcase a fully integrated, wireless, stand-alone unbiased photoelectrochemical cell (PEC) for the conversion of CO2 and H2O to chemicals and fuels in gas phase. Simulated sunlight at 1 Sun intensity is used to drive the conversion reaction. Proof-of-concept experiments show that the device is operational in dilute CO2 streams (10% CO2, 2% H2O, Ar balance) as well as in concentrated CO2 streams (98% CO2, 2% H2O). With a Cu sheet as the cathode catalyst, the device offers a CO2 reduction selectivity of ~50%; when Cu2O nanorods are employed, the selectivity toward CO2 reduction increases to ~90%. Experiments related to improving the performance of the device, testing other catalyst materials, and detecting the products is ongoing. The cell is lightweight, built of earth-abundant materials, and easy to assemble and scale. Further, it operates in dilute CO2 streams and the gas-phase operation facilitates the separation of liquid products. Thus the device represents a promising avenue toward the direct conversion of CO2 from flue gas or even air, without the need to first capture the CO2. Figure 1- Chronoamperometry experiments when the device is under interval illumination with difference cathode materials; a) Cu2O Nanorods, b) Cu sheet. Figure 1