In the present study, spinel cobalt ferrite hierarchical flower-like microspheres (CoFe₂O₄-MS) are fabricated using a hydrothermal method and utilized as a biocompatible anode in microbial fuel cells (MFCs) for power generation. A maximum power density of 1964 mW m⁻² is achieved with CoFe₂O₄-MS in a mediator-less MFC using Escherichia coli as a biocatalyst and glucose as a fuel. The unprecedented power generation by CoFe₂O₄-MS can be attributed to (i) the morphology of the flower-like CoFe₂O₄-MS, with a rough surface and large surface area suitable for biofilm formation, (ii) the rapid immobilization of negatively charged E. coli cells on the positively charged CoFe₂O₄-MS, facilitating stronger bacterial adhesion between the bacterial cells and CoFe₂O₄-MS, which leads to lower contact resistance and advantageous interfacial properties with rapid electron transfer, and, more importantly, (iii) enhanced interfacial charge transfer due to the presence of multi-valent cations and multiple valence states in the highly electrocapacitive CoFe₂O₄-MS. Thus, the enrichment of electroactive E. coli on CoFe₂O₄-MS produces a large number of electron-shuttling endogenous redox mediators, which promotes efficient extracellular electron transfer between E. coli and the electrocapacitive CoFe₂O₄-MS during the oxidation of the substrate, thus generating higher power output.

在本研究中，尖晶石钴铁氧体分层花状微球（CoFe ₂ O ₄ -MS）是使用水热法制备的，并用作微生物燃料电池（MFCs）中的生物相容性阳极，用于发电。在无介体的MFC中，使用大肠杆菌作为生物催化剂，以葡萄糖为燃料，使用CoFe ₂ O ₄ -MS可实现1964 mW m ^-2的最大功率密度。CoFe ₂ O ₄ -MS空前的发电可以归因于（i）花状CoFe ₂ O ₄的形态-MS，具有适合生物膜形成的粗糙表面和大表面积，（ii）将带负电的大肠杆菌细胞快速固定在带正电的CoFe ₂ O ₄ -MS上，促进细菌细胞与CoFe之间更强的细菌粘附₂ O ₄ -MS，这导致较低的接触电阻和有利的界面性质以及快速的电子转移，并且更重要的是，（iii）由于在高电电容中存在多价阳离子和多个价态，因此界面电荷转移增强CoFe ₂ O ₄ -MS。因此，电活性大肠杆菌在CoFe ₂上的富集O ₄ -MS产生大量的电子穿梭内源性氧化还原介体，可在基质氧化过程中促进大肠杆菌和电电容CoFe ₂ O ₄ -MS之间有效的细胞外电子转移，从而产生更高的功率输出。