Enhanced bioelectrochemical performance of microbial fuel cell with titanium dioxide-attached dual metal organic frameworks grown on zinc aluminum - layered double hydroxide as cathode catalyst

The ortho-substituent effect regulating the separation of photogenerated carriers to efficiently photodegrade tetracycline on the surface of FeCo-based MOFs

It is feasible to improve the photodegradation efficiency of organic pollutants by metal-organic frameworks (MOF)-based semiconductors via ligand engineering. In this work, three (Fe/Co)-XBDC-based MOFs were synthesized by introducing different ortho-functional groups X (X = -H, -NO2, -NH2) next to the carboxyl group of the organic ligand (i.e., terephthalic acid). The analysis focused on the influence mechanism of the adjacent functional group effect of the ligand on the physicochemical properties of the material and the actual photodegradation activity of TC. Multiple pieces of evidences suggested that the differences in electron-induced and photocharge-transfer mechanisms of the above ortho functional groups affect the crystal morphology and photocatalytic activity of FeCo-MOF during pyrolysis. Interestingly, (Fe/Co)-NH2BDC exhibited the highest photocatalytic activity under neutral conditions. The results of density functional theory show that the introduction of a strong donor-NH2 group can enhance light absorption and act as an "electron pump" to supply electrons to the iron center, accelerating the separation and efficient transport of photogenerated carriers on the ligand-metal bridge. In conclusion, this study is a proposal for a strategy of structural regulation for the enhancement of the catalytic activity of (Fe/Co)-MOFs in the photodegradation of TC.

A pathway for promoting bioelectrochemical performance of microbial fuel cell by synthesizing graphite carbon nitride doped on single atom catalyst copper as cathode catalyst

In this study, a simple distributed feeding method was used to dope graphite phase carbon nitride (g-C₃N₄) on single atom catalyst (SAC) copper (Cu) to form composite material (Cu-SA/CN). Cu-SA/CN was formed by mutual doping of polyhedral block Cu and irregular g-C₃N₄. There were obvious crystal face peaks at 28.4, 43.3, 47.3 and 56.2°. Large solid Cu and small irregular g-C₃N₄ were successfully combined and C, Cu, N and O elements were uniformly distributed on the surface of Cu-SA/CN. The valence bond of N-CN, C-NC, CC and OH was found. When the Cu content was 0.03 mol, Cu-SA/CN3 showed excellent redox activity. The maximum power density of Cu-SA/CN3-MFC was 456.976 mW/m², the maximum voltage was 599 mV, which could be stable for 7 d. Cu-SA/CN3 was proved to provide more electrically active sites, strong catalytic oxygen reduction ability and conductivity.

Three-dimensional hierarchical flower-like bimetallic–organic materials in situ grown on carbon cloth and doped with sulfur as an air cathode in a microbial fuel cell

Herein, the output power density produced by Zn/Co-S-3DHFLM as the cathode catalyst of an MFC was higher than that of Co-3DHFLM.

Enhancing bioelectrochemical performance of two-dimensional material attached by covalent/metal organic frameworks as cathode catalyst for microbial fuel cells

In this study, covalent/metal organic framework and two-dimensional material (COF-300/ZIF-8@Ti₃AlC₂) were composited by a three-step distributed feed method for cathode catalyst in microbial fuel cells (MFCs). The growth of irregular cube-like COF-300/ZIF-8 on the Ti₃AlC₂ substrate was observed. Al, Zn, Ti, N, C and O elements were observed uniformly and more active sites were offered through it. The external output voltage of COF-300/ZIF-8@Ti₃AlC₂-MFC was 576 mV and this could be almost unchanged for 9 days. The external output power density was 587.01 mW/m², and that was 1.25 times of COF-300@Ti₃AlC₂-MFC (469.30 mW/m²) and 1.67 times of COF-300/ZIF-8-MFC (352.09 mW/m²). Ti₃AlC₂ enhanced the electrical conductivity of the composite by its rich surface functional groups and much more surface active sites. COF-300/ZIF-8 mixture improved the instability and disorder of the monomer. This study would supply technical support for the expanded request of composite materials in microbial electrochemistry.

Activated carbon supported Fe–Cu–NC as an efficient cathode catalyst for a microbial fuel cell

Herein, the output power density produced by Fe–Cu–NC-x as the cathode catalyst of a MFC was higher than that of the AC control.