Microbial electrosynthesis: carbonaceous electrode materials for CO₂ conversion

Area of Science:

• Electrochemistry
• Environmental Science
• Biotechnology

Background:

• Microbial electrosynthesis (MES) offers a sustainable method for converting carbon dioxide (CO2) into valuable chemicals and clean fuels.
• The efficiency of MES is significantly influenced by the cathode material, with carbonaceous materials being preferred for their biocompatibility, high surface area, and stability.
• Various carbon-based materials, including nanotubes, graphene, biochar, and MXenes, are explored as electrode materials in MES.

Purpose of the Study:

• To review the current state-of-the-art in microbial electrosynthesis (MES).
• To highlight the role of carbonaceous electrode materials in enhancing CO2 conversion efficiency.
• To discuss the potential of MES for producing rocket fuels and bioderived products, including applications for the Mars mission.

Main Methods:

• Review of thermodynamic and kinetic processes in MES-based CO2 conversion.
• Analysis of reactor types, electrolytes, and methods for biomass accumulation.
• Emphasis on carbonaceous electrode materials, including 3D bioprinting and surface modifications.

Main Results:

• Carbonaceous materials significantly enhance bacterial growth and electron transfer rates in MES cathodes.
• Waste-derived carbon and biochar show promise for improving CO2 conversion efficiency and promoting a circular economy.
• MES technology is a viable route for producing fuels and chemicals from CO2, with potential for extraterrestrial applications.

Conclusions:

• Microbial electrosynthesis, particularly with advanced carbonaceous electrodes, presents a promising sustainable technology for CO2 utilization.
• The use of biochar and waste-derived carbon materials can further enhance MES efficiency and contribute to a circular economy.
• MES holds potential for producing essential resources like rocket fuels from atmospheric CO2, relevant for future space missions.