Ternary Composite of Polyaniline Graphene and TiO₂ as a Bifunctional Catalyst to Enhance the Performance of Both the Bioanode and Cathode of a Microbial Fuel Cell

Microbial fuel cells (MFCs) are a potential sustainable energy resource by converting organic pollutants in wastewater to clean energy. The performance of MFCs is influenced directly by the electrode material. In this study, a ternary PANI-TiO₂-GN nanocomposite was used successfully to improve the performance of both the cathode and anode MFC. The PANI-TiO₂-GN catalyst exhibited better oxygen reduction reaction activity in the cathode, particularly as a superior catalyst for improved extracellular electron transfer to the anode. This behavior was attributed to the good electronic conductivity, long-term stability, and durability of the composite. The immobilization of bacteria and catalyst matrix in the anode facilitated more extracellular electron transfer (EET) to the anode, which further improved the performance of the MFCs. The application of PANI-TiO₂-GN as a bifunctional catalyst in both the cathode and anode helped decrease the cost of MFCs, making it more practical

Environmentally Sustainable Fabrication of Ag@<i>g‑</i>C₃N₄ Nanostructures and Their Multifunctional Efficacy as Antibacterial Agents and Photocatalysts

Noble-metal silver (Ag) nanoparticles (NPs) anchored/decorated onto polymeric graphitic carbon nitride (<i>g</i>-C₃N₄) as nanostructures (NSs) were prepared using modest and environment-friendly synthesis method with a developed-single-strain biofilm as a reducing implement. The as-fabricated NSs were characterized using standard characterization techniques. The nanosized and uniform AgNPs were well deposited onto the sheet-like matrix of <i>g</i>-C₃N₄ and exhibited good antimicrobial activity and superior photodegradation of dyes methylene blue (MB) and rhodamine B (RhB) dyes under visible-light illumination. The Ag@<i>g</i>-C₃N₄ NSs exhibited active and effective bactericidal performance and a survival test in counter to <i>Escherichia coli</i>, <i>Staphylococcus aureus</i>, and <i>Pseudomonas aeruginosa.</i> The as-fabricated NSs also exhibited superior visible-light photodegradation of MB and RhB in much less time as compared to other reports. Ag@<i>g</i>-C₃N₄ NSs (3 mM) showed superior photocatalytic measurements under visible-light irradiation: ∼100% MB degradation and ∼89% of RhB degradation in 210 and 250 min, respectively. The obtained results indicate that the AgNPs were well deposited onto the <i>g</i>-C₃N₄ structure, which decreases the charge recombination rate of photogenerated electrons and holes and extends the performance of pure <i>g</i>-C₃N₄ under visible light. In conclusion, the as-fabricated Ag@<i>g</i>-C₃N₄ NSs are keen nanostructured materials that can be applied as antimicrobial materials and visible-light-induced photocatalysts