阴极表面亲疏水性对含氧自由基原位生成和避免产电菌膜过度生长的影响机制

微生物燃料电池(MFC)空气阴极过度生长的菌膜会使O2还原(ORR)的电荷传递受阻、废水产电效率下降；阴极表面亲疏水性(润湿性)对菌膜粘附与ORR路径有很大影响。项目通过调控催化剂表面性质，构建两电子ORR产物—H2O2催化分解(•OH、O_2^(•-)等)和不利于细菌附着与定植的阴极表面，实现原位抑制细菌成膜与过度生长以获得产电稳定性。具体以ZIF-67为骨架制备氮掺杂纳米碳层包裹的四氧化三钴/氮化钴@晶态碳(Co3O4/CoN@GC@NCL)催化剂；改变材料表面/层亲疏水程度(活性组分、纳米壳层厚度和结构)来调控气液两相中O2传输和两电子途径(H2O2)占比，进而控制含氧自由基的原位生成与利用；根据细菌粘附和材料-细菌交互作用(Zeta电位和DLVO理论计算)分析，优化材料亲疏水性和催化活性。根据阴极亲疏水性与产电性能关联，揭示以Co3O4/CoN@GC@NCL为阴极的MFC产电机制。

The overgrowth of biofilm formed on the surface of air cathode of microbial fuel cell (MFC) can hinder the charge transfer in the oxygen reduction reaction (ORR) process, resulting in a great decrease in the efficiency of bio-electricity generation from wastewater. Hydrophilicity/hydrophobicity (wettability) of the cathode surface has a great effect on bacterial adhesion and ORR catalytic pathway. This project aims to adjust the hydrophilicity/hydrophobicity of the cathode surface to establish the cathode surface with stable bio-electricity generation by strengthening the rapid decomposition of H2O2 (•OH, O_2^(•-) and H2O•) (the intermediate in two-electrons ORR pathway) and the inhibition of the biofilm attachment and growth on the cathode. ZIF-67 with a tetrahedral structure is used as a porous skeleton to prepare the nitrogen-doped nano carbon-thin-layer-coated tricobalt tetroxide/cobalt nitride@crystallized carbon (Co3O4/CoN@GC@NCL) core-shell catalysts. The degree of the hydrophilicity/hydrophobicity (including the active components, thickness of nano-shell and structure) of surface/layer is changed to regulate the O2 transport and the two-electron ORR pathway (H2O2) ratio in the gas-liquid two-phase, thereby controlling the in-situ catalysis and utilization of free radicals. Based on the analyses of the bacterial adhesion investigation and material-bacteria interactions (Zeta potential and DLVO theoretical calculations), the hydrophilicity/hydrophobicity and catalytic activity of the catalysts are optimized. According to the correlation between the hydrophilicity/hydrophobicity of the cathode and the bio-electricity generation performance, the electricity generation mechanism of MFC with Co3O4/CoN@GC@NCL materials as the cathode catalysts will be revealed.