Introducing an affordable catalyst for biohydrogen production in microbial electrolysis cells

Area of Science:

• Materials Science
• Electrochemistry
• Environmental Engineering

Background:

• Microbial electrolysis cells (MECs) require efficient and cost-effective cathode catalysts.
• Conventional platinum (Pt) catalysts are expensive, limiting large-scale MEC applications.
• Developing alternative cathode materials is crucial for advancing MEC technology.

Purpose of the Study:

• To fabricate and assess a novel cathode electrode assembly using polyaniline (PANI) and graphene on stainless steel mesh (SSM).
• To evaluate the performance of the SSM/PANI/graphene cathode as a cost-effective alternative to Pt-based cathodes in MECs.
• To investigate the potential of this modified cathode for larger-scale MEC applications, particularly in dairy wastewater treatment.

Main Methods:

• Fabrication of a stainless steel mesh (SSM) supported cathode electrode incorporating polyaniline (PANI) and graphene.
• Performance evaluation of the SSM/PANI/graphene cathode in a microbial electrolysis cell (MEC) fed with dairy wastewater.
• Characterization of the cathode material using Fourier transform infrared spectroscopy (FTIR), linear sweep voltammetry (LSV), scanning electron microscopy (SEM), and atomic force microscopy (AFM).

Main Results:

• The SSM/PANI/graphene cathode achieved a maximum hydrogen production rate of 0.805 m³ H₂ m⁻³ anolyte day⁻¹ and 82% COD removal at 1 V.
• Performance metrics were comparable to Pt-based cathodes, with only 20% lower hydrogen production and 7% lower COD removal.
• Coulombic efficiencies were 56.67% for SSM/PANI/graphene and 64.48% for SSM/Pt.
• The fabrication cost of the modified cathode was 50% lower than conventional Pt-on-carbon cloth cathodes.

Conclusions:

• The developed SSM/PANI/graphene cathode is a viable, cost-effective alternative to expensive Pt-based cathodes for MECs.
• This material demonstrates significant potential for efficient hydrogen production and wastewater treatment in large-scale MEC applications.
• The study highlights the successful integration of PANI and graphene for enhanced cathode performance in bioelectrochemical systems.