Improving the bioelectrochemical performance of microbial fuel cells using single-atom catalyst nickel combined with graphitic carbon nitride as the cathode catalyst

Single atom catalyst (SAC) nickel (Ni) combined with graphitic carbon nitride (g-C3N4) was prepared following two simple hydrothermal methods. The composite material (Ni-SA/CN) was doped with g-C3N4 in the polyhedral solid block of SAC Ni. Prominent peaks at 37.3, 43.3, and 62.9° in the X-ray diffraction profiles were observed, and Ni-SA/CN was formed by the mutual doping of bulk SAC Ni and g-C3N4. The peaks corresponding to Cl 2p (198.74 eV), C 1s (284.66 eV), O 1s (532.73 eV), Ni 2p (855.91 eV), and N 1s (399.19 eV) were observed. The Ni-SA/CN3 system exhibited optimal electrochemical performance when the Ni content was 0.015 mol, and the maximum power density was recorded to be 430 mW/m2 when Ni-SA/CN3 was used as the microbial fuel cell (MFC) cathode. Ni-SA/CN3 demonstrated favorable surface characteristics, high activity, and high catalytic activity for MFCs.