Fe-Ni alloy modified Zr-based MOF derivatives as bioelectrocatalyst for regulating multipath EET efficiency and biofilm electrogenic activity

As a green conversion device, the electricity performance of microbial fuel cell (MFC) was mainly affected by the extracellular electron transfer (EET) process of the biofilm. This paper presented the fabrication and characterization of carbonized derivatives composed with alloy nanoparticles (NPs) derived from Zr-based metal organic frameworks, which exhibited biocompatibility and high electrocatalytic activity. As the results of bioanodes, the charge transfer resistance decreased from 5.60 Ω (Zr-C) to 0.61 Ω (Fe/Ni-Zr-C), and the exchange current density increased from 0.56 mA/cm 2 (Zr-C) to 1.40 mA/cm 2 (Fe/Ni-Zr-C). Electrochemical tests and density functional theory (DFT) confirmed that Fe-Ni alloy NPs promoted the rapid transfer of electrons within the electrode and improved the EET efficiency mediated with the flavin compounds. High throughput sequencing and PICRUSt verified the specific screening function of Fe-Ni alloy for electrogenic bacteria (mainly Geoalkalibacter) and the promoting effect on the expression of flavin-related proteins in biofilm. The maximum power density of Fe/Ni-Zr-C MFC (5.09 W/m 2 ) was higher than that of Ni-Zr-C (4.19 W/m 2 ), Fe-Zr-C (3.58 W/m 2 ) and Zr-C (3.09 W/m 2 ) MFCs. Fe/Ni-Zr-C material can act as an economical and high-performance bioelectrocatalyst to improve the power generation capability of MFC by improving EET rate and energy conversion efficiency of biofilm.