Enhancing Microbial Fuel Cell (MFC) Activity by Incorporating Polypyrrole/MXene Composite as an Anode Material

Abstract

Microbial fuel cells (MFC) have been recognized as a promising green and clean electricity generation device. The anode is critical to the electricity generation process within MFC. Microbes in the anodic chamber oxidize organic substrates, releasing protons and electrons in the process. These electrons are subsequently transferred to the anode surface, where they generate an electric current. When protons from the anode pass through a proton exchange membrane (PEM) and electrons passing from external circuit combine with oxygen to form water at cathode, the electrochemical circuit is completed. Improving MFC performance using MXene (Ti3C2) as anode material is a promising method. MXene is a material with a large surface area and tunable chemical properties. Our goal is to maximize the catalytic capabilities of MXene layers to improve the efficiency of MFCs by depositing it on the anode surface and speeding up electron transmission. For this, Polypyrrole (PPy) can boost the redox activity, stability and conductivity of the electrode surface. The Polypyrrole/MXene composite adds a new dimension to this research. Hydrofluoric acid (HF) etching approach is being used to exfoliate MXene sheets, followed by in-situ polymerization of pyrrole to generate a PPy/MXene composite. The MFC fabricated with as prepared PPy/MXene@GF anode had the highest power density of 264 mW/m2 and a maximum output voltage of 281 mV, then that of MXene@GF (197 mW/m2 , 157 mV) and unmodified Graphite felt (GF) (45 mW/m2 , 101 mV). This improved performance can be attributed to the material's reduced charge transfer resistance (Rct) and solution resistance (Rs) combined with higher bacterium affinity, resulting in increased extracellular electron transfer (EET) efficiency. This study shows that the PPy/MXene composite possesses good potential as an anode in terms of MFC power generation.