Continuous Flow Photoelectrochemical Reactor with Gas Permeable Photocathode: Enhanced Photocurrent and Partial...

Area of Science:

• Electrochemistry
• Materials Science
• Chemical Engineering

Background:

• Photoelectrochemical (PEC) reduction of carbon dioxide (CO2) offers a sustainable route to valuable chemicals.
• Traditional PEC systems face limitations in CO2 diffusion, hindering production rates, especially at high current densities.

Purpose of the Study:

• To develop a continuous flow PEC reactor with a gas-permeable photocathode for enhanced CO2 reduction.
• To overcome diffusion limitations and improve production rates and stability in PEC CO2 conversion.

Main Methods:

• Incorporation of a gas-permeable photocathode (Ag-TiO2 on carbon paper) into a continuous flow PEC reactor.
• Direct supply of CO2 gas to the photocathode-electrolyte interface via controlled pressure and flow.
• Illumination through a quartz window with flowing liquid electrolyte.

Main Results:

• The continuous flow PEC reactor demonstrated significantly improved CO2 reduction performance compared to traditional H-cells.
• Achieved approximately 10-fold increase in CO faradaic efficiency, 30-fold increase in production rate, and 16-fold increase in stability.
• Photocurrent density was found to be sensitive to CO2 gas flow/pressure and electrolyte flow rates.

Conclusions:

• The developed continuous gas-liquid flow PEC reactor effectively addresses diffusion limitations in CO2 reduction.
• This reactor design shows great promise for efficient and stable PEC conversion of CO2 and other PEC reactions.