Synthesis and performance evaluation of polypyrrole/titanium oxide composite as an electrocatalyst for simultaneous power generation and wastewater treatment in bioelectrochemical systems

Microbial fuel cells (MFCs) offer a promising and sustainable approach to wastewater treatment by harnessing the natural abilities of microorganisms to degrade organic pollutants and simultaneously generating electrical energy. However, the effectiveness of power generation in MFCs is heavily influenced by the choice of cathode catalyst. The use of platinum (Pt), the preferred catalyst material, is limited in large-scale applications due to its high cost. In this present study, polypyrrole/titanium oxide (Ppy/TiO₂) was synthesized and investigated as cathode catalysts in bioelectrochemical cells. Field emission scanning electron microscopy (FE-SEM) confirms the rectangular structure of TiO₂ covered by Ppy material in Ppy/TiO₂ composite. X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS) also reveal the distinct characteristics and purity of Ppy/TiO₂ composite materials. The performance of the Ppy/TiO₂ (1:1) ratio shows better catalytic activity and electrical conductivity (R_total = 19.418 Ω) in comparison with other ratios (1:0, 1:1, 3:1, 1:2, 1:3, and 0:1). The Ppy/TiO₂ catalyst reaches a maximum power density of 0.630 W m⁻², comparable to platinum catalyst (0.853 W m⁻²). In addition, the voltage stability analysis for the Ppy/TiO₂ catalyst over five cycles yields a stable voltage of 0.675 ± 0.005 V at 100 Ω. This study highlights the performance comparison of Ppy/TiO₂ catalysts and their potential as cost-effective alternatives to expensive Pt/C cathode catalysts in sediment microbial fuel cells (SCMFCs), with significant implications for wastewater treatment.