Integrated Electrochemical Conversion of Plastic Waste and CO₂ to Formate Using Non-Noble-Metal Catalysts: In Situ...

Area of Science:

• Electrochemistry
• Materials Science
• Environmental Science

Background:

• Poly(ethylene terephthalate) (PET) plastic waste is a significant environmental pollutant, contributing to CO2 emissions.
• Existing methods for PET recycling often involve high energy consumption or produce less valuable products.

Purpose of the Study:

• To develop an innovative electrochemical approach for simultaneous Poly(ethylene terephthalate) (PET) hydrolysate oxidation and CO2 reduction.
• To produce valuable fuels, specifically formate, from plastic waste and CO2 in a single cell system.

Main Methods:

• Anodic oxidation of 3D carbon felt (CF) to create activated carbon felt (aCF).
• Electrochemical deposition of bismuth oxide carbonate (Bi2O2CO3) and nickel cobalt phosphate (NiCoPOx) onto aCF for CO2 reduction and PET oxidation, respectively.
• Utilized *in situ* Raman analysis to identify reaction intermediates.

Main Results:

• Achieved high Faradaic efficiencies (>90%) for both the CO2 reduction reaction (CO2RR) and PET hydrolysate oxidation half-cell reactions.
• Demonstrated a combined Faradaic efficiency of up to 158% for both reactions at a low cell voltage of 1.8 V.
• Identified MOOH (M = Ni, Co) intermediates as active sites for PET oxidation.

Conclusions:

• This research showcases a sustainable method for plastic waste valorization and CO2 utilization.
• The developed system efficiently converts PET and CO2 into formate using cost-effective, non-noble metal catalysts.
• Highlights the potential for electrochemical processes in creating valuable fuels from waste streams.