Synthesis of low cost organometallic-type catalysts for their application in microbial fuel cell technology

ZrP2O7 as a Cathodic Material in Single-Chamber MFC for Bioenergy Production

The present work is the first investigation of the electrocatalytic performances of ZrP₂O₇ as a cathode in a single-chamber Microbial Fuel Cell (MFC) for the conversion of chemical energy from wastewater to bioelectricity. This catalyst was prepared by a coprecipitation method, then characterized by X-ray diffraction analysis (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), ultraviolet-visible-near-infrared spectrophotometry (UV-Vis-NIR), and cyclic voltammetry analyses. The acid-basic characteristics of the surface were probed by using 2-butanol decomposition. The conversion of 2-butanol occurs essentially through the dehydrating reaction, indicating the predominantly acidic character of the solid. The electrochemical test shows that the studied cathode material is electroactive. In addition, the ZrP₂O₇ in the MFC configuration exhibited high performance in terms of bioelectricity generation, giving a maximum output power density of around 449 mW m^-2; moreover, it was active for wastewater treatment, reducing the chemical oxygen demand (COD) charge to 50% after three days of reaction.

Platinum nanoparticles embedded into polyaniline on carbon cloth: improvement of oxygen reduction at cathode of microbial fuel cell used for conversion of medicinal plant wastes into bio-energy

A microbial fuel cell is a biological electrochemical system that extracts electrons stored in organic matter by oxidation using catalytic properties of microorganisms at bioanode. The major problem in such device, is however limited power production due to slow kinetic of oxygen reduction at cathode. It is worthwhile to develop new materials that fulfil these requirements. The polymerization of aniline onto carbon cloth for effective electrodeposition of platinum nanoparticles has been carried out by chronoamperometry and cyclic voltammetry. Three materials were thus elaborated, namely pristine carbon cloth, carbon cloth modified with platinum and carbon cloth modified by polymerization of aniline for immobilization of Pt-nanoparticles. The FTIR spectroscopy analysis revealed characteristic band located in 1720-1650 cm^-1, attributed to imine function, main component in skeleton of polymer PANI chain. The modified materials have been utilized as cathode in cell inoculated with medicinal plant wastes for improvement of oxygen reduction. Modified cathode with CC-PANI-Pt proved higher performances in all respects: increase of cell voltage from 338 to 765 mV and power density from 862 to 1510 mW/m² and abatement of COD of microbial inoculum leachate to 88%. Another feature of cell with modified cathode CC-PANI-Pt, was the enormous electric charge density harvested upon oxidation of 1 mL of acetate 7.62 C/cm² compared to that of cell with pristine CC cathode 0.54 C/cm². Nevertheless, coulombic efficiency for conversion of medicinal plant wastes into bioenergy was relatively lower 9%, making in evidence that elaborated electrochemical device was rather efficient and benificial environmentally than energetically.

Tungsten oxide as electrocatalyst for improved power generation and wastewater treatment in microbial fuel cell

Microbial fuel cell (MFC) is a device that oxidizes the organic matter present in wastewater and simultaneously generates electricity from it. For practical applications, the power production of MFCs needs to be enhanced and the use of novel anode and cathode catalyst can certainly help in this regard. Such a novel catalyst, WO₃, was explored as both anode and cathode catalyst in this study. Performance of MFCs was enhanced when WO₃ was used as an electrocatalyst. The maximum power density of MFC was increased by five times when WO₃ was used as anode catalyst and by four times when it was used as cathode catalyst as compared to control MFC using electrode without any catalyst. Almost six times increment in maximum power production of MFC was observed when WO₃ was used as catalyst on both the electrodes. Electrochemical analysis of WO₃ also proved that it could enhance the current density of the modified electrode owing to its electrochemical catalytic properties. Furthermore, chemical oxygen demand (COD) removal of MFC having WO₃ coated electrodes was also observed to be higher, thus suggesting an overall enhancement in the performance of MFC by the use of WO₃ as an electrocatalyst.