Poly(aniline-2-sulfonic acid-co-aniline) modified nickel-doped carbon catalyst for power generation in microbial fuel cells

Microbial fuel cells (MFCs) are self-powered devices used for power generation. However, the advancement of the technology is hindered poor durability, sluggish electrochemical reaction kinetics, and high capital costs, especially for cathode materials. In this study, we developed a nickel (Ni) chelate catalyst derived from thiourea-formaldehyde resins (Ni-TF), which incorporates sulphur (S) and nitrogen (N) groups, to enhance the oxygen reduction reaction (ORR) kinetics. To improve the electrical conductivity and electron transfer and to investigate the influence of N and S content, Ni-TF particles were interwoven with polyaniline and aniline-2-sulfonic acid-co-aniline, respectively. The integration of self-doped electroactive polymer with Ni-TF significantly enhanced the catalytic activity of the resulting composite (SPAN-PAN/Ni-SNC). SPAN-PAN/Ni-SNC exhibited a high oxygen reduction potential of 0.335 V (vs. RHE) at −0.018 mA, superior stability, and a low charge transfer resistance of 95.1 Ω. Furthermore, SPAN-PAN/Ni-SNC recorded a maximum power density of 2045.1 mW m−2 at a current density of 8343.8 mA m−2, compared to 873.67 mW m−2 and 5453.6 mA m−2 for Ni-SNC. This improvement is attributed to the synergy between the interwoven Ni-SNC and conducting copolymer. These findings indicate that encapsulating metal-doped catalysts within heteroatom-doped carbons can enhance long-term fuel cell performance and related applications.