Reduced Graphene Oxide (rGO) was coated on Carbon Felt (CF) in order to design a novel cathode applied in the Electro-Fenton (EF) reaction for decontamination of wastewater polluted with Persistent Organic Pollutants (POPs). The new cathode was fabricated by an electrophoretic deposition of Graphene Oxide (GO) followed by its electrochemical reduction at a current density of À1.5 mA cm À2 for 10 min. The modified electrode and GO were characterized by SEM, AFM, XRD and XPS, showing the presence of rGO after optimization of the electrochemical conditions of synthesis. Electrode modification has improved the CF electrochemical properties as proved by the decrease of the charge-transfer resistance (R ct ) determined by electrochemical impedance spectroscopy (EIS) and the increase of the CV response (2.5 times) of the Fe III /Fe II couple used as a redox probe.Degradation of Acid Orange 7 (AO7), a model pollutant molecule, was monitored by UV-Vis spectrophotometry at the selected single wavelength l ¼ 485 nm. The results show that the degradation kinetics were 2 times higher on the graphene modified cathode compared to raw carbon felt proving the efficiency of this modification process.

(2013). Aqueous dispersions of reduced graphene oxide and multi wall carbon nanotubes for enhanced glucose oxidase bioelectrode performance. Carbon, 61 (September), 467-475. Aqueous dispersions of reduced graphene oxide and multi wall carbon nanotubes for enhanced glucose oxidase bioelectrode performance AbstractAqueous dispersions of reduced graphene oxide (rGO) and multi walled carbon nanotubes (MWCNT) were fabricated through a modified chemical reduction method. The significant advantage of the method developed here is the omission of any stabilising compound or organic solvent to obtain stable rGO-MWCNT dispersions. Significantly biological entities, in this case the enzyme glucose oxidase (GOx), can be successfully incorporated into the dispersion. These dispersions were characterised using XPS, SEM, zeta potential and particle size measurements which showed that the dispersion stability is not sacrificed with the addition of GOx, and significantly, the electrical properties of the rGO and MWCNTs are maintained. In this study, rGO acts as an effective dispersing agent for MWCNTs and does not affect the solubility or electroactivity of the GOx. Bioelectrodes fabricated from these rGO-MWCNT-GOx dispersions were characterised electrochemically to test their feasibility in facilitating direct electron transfer (DET) from the redox centre of the enzyme to the electrode. The DET results showed that the specific catalytic current generated at an optimised rGO-MWCNT-GOx electrode was 72 uA/ug which is 144 times more efficient than other literature values for similar systems. The remarkable specific catalytic current can be attributed to the use of purified enzyme, the efficiency of charge transfer within the rGO-MWCNT composite and the ability of the electrode to facilitate direct electron transfer. Abstract:Aqueous dispersions of reduced Graphene Oxide (rGO) and multi walled carbon nanotubes (MWCNT) were fabricated through a modified chemical reduction method. The significant advantage of the method developed here is the omission of any stabilizing compound or organic solvent to obtain stable rGO-MWCNT dispersions. Significantly biological entities, in this case the enzyme glucose oxidase (GOx), can be successfully incorporated into the dispersion. These dispersions were characterised using XPS, SEM, zeta potential and particle size measurements which showed that the dispersion stability is not sacrificed with the addition of GOx, and significantly, the electrical properties of the rGO and MWCNTs are maintained. In this study, rGO acts as an effective dispersing agent for MWCNTs and does not affect the solubility or electroactivity of the GOx.Bioelectrodes fabricated from these rGO-MWCNT-GOx dispersions were characterised electrochemically to test their feasibility in facilitating direct electron transfer (DET) from the redox centre of the enzyme to the electrode. The DET results showed that the specific catalytic current generated at an optimized rGO-MWCNT-GOx electrode was 72 µA/µg GOx, which is 144 times m...

The change in charge-transfer resistance (Rct) was found to be linear with DCL concentration in the 30 pM-1 µM range. The detection limit was calculated to be 0.02 nM. The improvement of the limit of detection can be mainly attributed to the threedimensional environment of the hydrogel matrix which improves the grafting density of aptamer and the affinity of the aptamer to DCL.

No abstract

No abstract

In order to enhance the power output of microbial fuel cell as well as its stability, the development of a new type of anode is essential. The purpose of this work is to modify a stainless steel foam, using the layer-by-layer self-assembly technique, with rGO (reduced graphene oxide) and PEI (polyethyleneimine). The efficiency of this kind of modification has been investigated to determine the supply of graphene in term of electricity generation and stability. Under an applied voltage, which is used to form an electroactive biofilm, the modified stainless steel foam (SSF/(PEI/rGO)5) exhibited a current 50 times higher than the blank anode. The roughness of the SSF/(PEI/rGO)5 observed by SEM (scanning electron microscopy) is more favorable to attach more bacteria on it. Also, graphene improved the stability of the electrode as no response where observed for the blank anode after 18 days meanwhile the SSF/(PEI/rGO)5 was still running after 54 days.