Effect of Anode Surface Roughness on Power Generation in Microbial Fuel Cells

2012 ◽  
Author(s):  
Zhou Ye ◽  
Junbo Hou ◽  
Michael W. Ellis ◽  
Bahareh Behkam
Keyword(s):  
Surface Roughness ◽  
Fuel Cells ◽  
Glassy Carbon ◽  
Microbial Fuel Cells ◽  
Electrochemical Impedance ◽  
Charge Transfer Resistance ◽  
Electrode System ◽  
Anode Surface ◽  
Transfer Resistance ◽  
Rough Electrode

A three-electrode system was used to study the effect of anode surface roughness on the performance of microbial fuel cells (MFCs). Two glassy carbon plates were polished to uniform roughness of the orders of magnitude of 10s of nm and 100s of nm. Atomic force microscopy (AFM) was used to quantify the roughness as well as the 3D topography of the surfaces. Multiple electrochemical methods including potentiostatic tests, potentiodynamic tests, and electrochemical impedance spectroscopy (EIS) were utilized to monitor the performance of the glassy carbon electrodes. After 275 hours of experimentation, the current density generated by the rough electrode was much higher than that generated by the smooth one. Furthermore, the charge-transfer resistance of the rough electrode was lower than that of the smooth one. The better electrochemical performance of the rough surface may be due to denser biofilm grown on the surface, which was observed by scanning electron microscopy (SEM).

scholarly journals Electrochemical behaviour of poly(3,4-ethylenedioxytiophene) modified glassy carbon electrodes after overoxidation − the influence of the substrate on the charge transfer resistance

2018 ◽  
Author(s):  
Dora Zalka ◽  
Soma Vesztergom ◽  
Mária Ujvári ◽  
Gyözö Láng
Keyword(s):  
Charge Transfer ◽  
Glassy Carbon ◽  
Electrochemical Impedance ◽  
Electrochemical Behaviour ◽  
Mechanistic Explanation ◽  
Time Instant ◽  
Charge Transfer Resistance ◽  
Polymer Chains ◽  
Transfer Resistance ◽  
Impedance Measurements

<p class="PaperAbstract">Time dependence of the electrochemical impedance of an overoxidized glassy carbon|poly(3,4-ethylenedioxytiophene) (PEDOT)|0.1 mol·dm<sup>-3</sup> sulfuric acid (aq.) elec­trode has been investigated. To follow the changes occurring at the film/substrate interface after the overoxidation procedure, successive impedance measurements were carried out. Although the system is intrinsically nonstationary, the charge transfer resis­tance (R<sub>ct</sub>) cor<strong>­</strong>res<strong>­</strong>ponding to different time instants could be determined by using the so-called 4-dimensional analysis method. The same post-experimental mathematic­cal/ana­lytical procedure could be used also for the estimation of the charge transfer resistance corresponding to the time instant just after overoxidation of the PEDOT film. The increase of the charge transfer resistance of the overoxidized system with respect to that of the pristine electrode suggests that during overoxidation the electrochemical activity of the film decreases and the charge transfer process at the metal/film interface beco­mes more hindered. After the overoxidation procedure, when the electrode potential was held in the “stability region” (at E = 0.4 V vs. SSCE in the present case) the R<sub>ct</sub> decre­ased continuously with experiment time to a value somewhat higher than that of the pristine electrode.<strong> </strong>By comparing the properties of the GC|PEDOT|0.1 M H<sub>2</sub>SO<sub>4</sub> and the Au|PEDOT|0.1 M H<sub>2</sub>SO<sub>4</sub> electrodes a possible mechanistic explanation for the observed behavior has been proposed. This is based on the assumption that in the case of the GC|PEDOT|0.1 M H<sub>2</sub>SO<sub>4</sub> electrode two processes may occur simultaneously during the impedance measurements: (a) reduction of the oxidized surface of the GC substrate, including the reduction of the oxygen-containing surface functionalities and (b) read­sorption of the polymer chains (polymer chain ends) on the surface.<strong></strong></p>

PREPARATION AND CHARACTERIZATION OF A POLY(PYRROLYL METHANE)/MULTIWALLED CARBON NANOTUBES COMPOSITES

NANO ◽  
2013 ◽  
Vol 08 (06) ◽  
pp. 1350063
Author(s):  
JINXIAN LIN ◽  
PAN WANG ◽  
YUYING ZHENG
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Multiwalled Carbon Nanotubes ◽  
Electrochemical Impedance ◽  
Charge Transfer Resistance ◽  
Electrode System ◽  
X Ray Diffraction ◽  
Multiwalled Carbon ◽  
Transfer Resistance ◽  
Transmission Electron

A poly(pyrrolyl methane) (Poly[pyrrole-2, 5-diyl(4-methoxybenzylidane)], PPDMOBA)/multiwalled carbon nanotubes (MWNTs) composites are fabricated by in situ chemical polycondensation of pyrrole and 4-methoxybenzaldehyde on MWNTs. The structure, morphology, thermal stability and electrical property of the resulting composites are investigated via fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), thermogravimetric analysis (TGA), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and a four-probe method. The electrochemical performance of the composites is determined in a three-electrode system using cyclic voltammetry (CV), galvanostatic charge–discharge (GCD) and electrochemical impedance spectroscopy (EIS) techniques. FTIR, FESEM and TEM confirm that the composites have been successfully prepared, and PPDMOBA is uniformly dispersed in MWNTs. Electrical conductivity of PPDMOBA/MWNTs composites is 1.39 S cm-1, which is significantly larger than that of pristine PPDMOBA. The specific capacitance and charge transfer resistance of the composites is 56 F g-1 (1 mA cm-2) and 0.3Ω, respectively.

scholarly journals Enhancement of the Start-Up Time for Microliter-Scale Microbial Fuel Cells (µMFCs) via the Surface Modification of Gold Electrodes

Micromachines ◽  
2020 ◽  
Vol 11 (7) ◽  
pp. 703
Author(s):  
Begüm Şen-Doğan ◽  
Meltem Okan ◽  
Nilüfer Afşar-Erkal ◽  
Ebru Özgür ◽  
Özge Zorlu ◽  
...  
Keyword(s):  
Surface Modification ◽  
Fuel Cells ◽  
Microbial Fuel Cells ◽  
Microelectromechanical Systems ◽  
Electrochemical Impedance ◽  
Shewanella Oneidensis ◽  
Bacterial Attachment ◽  
Anode Surface ◽  
Sem Images ◽  
Start Up

Microbial Fuel Cells (MFCs) are biological fuel cells based on the oxidation of fuels by electrogenic bacteria to generate an electric current in electrochemical cells. There are several methods that can be employed to improve their performance. In this study, the effects of gold surface modification with different thiol molecules were investigated for their implementation as anode electrodes in micro-scale MFCs (µMFCs). Several double-chamber µMFCs with 10.4 µL anode and cathode chambers were fabricated using silicon-microelectromechanical systems (MEMS) fabrication technology. µMFC systems assembled with modified gold anodes were operated under anaerobic conditions with the continuous feeding of anolyte and catholyte to compare the effect of different thiol molecules on the biofilm formation of Shewanella oneidensis MR-1. Performances were evaluated using polarization curves, Electrochemical Impedance Spectroscopy (EIS), and Scanning Electron Microcopy (SEM). The results showed that µMFCs modified with thiol self-assembled monolayers (SAMs) (cysteamine and 11-MUA) resulted in more than a 50% reduction in start-up times due to better bacterial attachment on the anode surface. Both 11-MUA and cysteamine modifications resulted in dense biofilms, as observed in SEM images. The power output was found to be similar in cysteamine-modified and bare gold µMFCs. The power and current densities obtained in this study were comparable to those reported in similar studies in the literature.

Improved Electrochemical and Mechanical Properties of Poly(vinylpyrrolidone)/Nafion® Membrane for Fuel Cell Applications

2020 ◽  
Vol 20 (12) ◽  
pp. 7793-7799
Author(s):  
M. D. Lutful Kabir ◽  
Subir Paul ◽  
Sang-June Choi ◽  
Hee Jin Kim
Keyword(s):  
Fuel Cells ◽  
Proton Exchange Membrane ◽  
Electrochemical Impedance ◽  
Chemical Properties ◽  
Charge Transfer Resistance ◽  
Vital Role ◽  
Exchange Capacity ◽  
Proton Exchange ◽  
Membrane Electrode ◽  
Transfer Resistance

A novel blend of membranes made of Nafion® and poly(vinylpyrrolidone) (PVP) was prepared and characterized to investigate its applicability in proton exchange membrane fuel cells (PEMFCs). In addition to being effectively proton conductive, the membranes exhibited better mechanical strength, chemical stability, and adequate water retention ability, as well as ion exchange capacity comparable to that of cast Nafion® membrane. The data obtained from an electrochemical impedance spectroscopy (EIS) fitting of the fuel cells revealed the membrane electrode assemblies (MEAs) made of 0.5 wt.% PVP/Nafion® had lower ohmic and charge transfer resistance compared with that of the Nafion® membrane. The intermolecular interactions and morphology of these membranes were assessed using Fourier-transform infrared spectroscopy and field-emission scanning electron microscopy. The results of the performance curve indicate that the introduction of PVP as a modifier played a vital role in improving membrane performance. Accordingly, this solution-casted polymer electrolyte membrane with suitable PVP content offers a simple way to improve electrochemical, mechanical, and chemical properties, and thereby promises the prospect of use in low-temperature PEMFCs.

scholarly journals Operation and Electro(chemical) characterization of a microbial fuel cell stack fed with fermentable household waste extract

2019 ◽  
Keyword(s):  
Microbial Fuel Cells ◽  
Electrochemical Impedance ◽  
Voltage Drop ◽  
Chemical Characterization ◽  
Linear Sweep Voltammetry ◽  
Charge Transfer Resistance ◽  
Household Waste ◽  
Transfer Resistance ◽  
In Series ◽  
Waste Extract

<p>Two identical four air-cathode single chamber membrane-less microbial fuel cells were stacked and tested under in series and in parallel electrical configurations. Fermentable household waste extract (FORBI; 0.8 g COD/L) was used as substrate, in all cases. Linear Sweep Voltammetry (LSV) was carried out for the construction of polarization curves which revealed that the highest power ouput (3.88 mW) was obtained under parallel connection as in series connection was found lower due to voltage drop phenomena. Electrochemical Impedance Spectroscopy measurements (EIS) gave an insight in the electrochemical processes occurring within the stack under both electrical connections. The contribution of the individual resistances to the overall internal resistance was defined, designating the significant role of the solution resistance (Rs) and the charge transfer resistance (RCT) under closed circuit conditions.</p>

scholarly journals Controllable Synthesis of h-WO3 Nanoflakes by L-lysine Assisted Hydrothermal Route and Electrochemical Characterization of Nanoflakes Modified Glassy Carbon Electrode

2018 ◽  
Vol 1 (1) ◽  
pp. 7
Author(s):  
Vijaya Kumar Gangaiah ◽  
Ashoka Siddaramanna ◽  
Prashanth Shivappa Adarakatti ◽  
Gujjarahalli Thimanna Chandrappa
Keyword(s):  
Glassy Carbon Electrode ◽  
Glassy Carbon ◽  
Ostwald Ripening ◽  
Electrochemical Impedance ◽  
Hydrothermal Reaction ◽  
Charge Transfer Resistance ◽  
Carbon Electrode ◽  
Modified Glassy Carbon Electrode ◽  
Hydrothermal Route ◽  
Transfer Resistance

<p>Hexagonal tungsten trioxide (h-WO3) nanoflakes have been synthesized by a hydrothermal approach using L-lysine as the shape directing agent. The influence of hydrothermal reaction time and L-lysine content on the morphology of h-WO3 was investigated. The experimental results showed that the nanoflake morphology could be achieved at higher concentration of L-lysine. Based on the evolution of nanoflake morphology as a function of hydro-thermal duration, a “dissolution-crystallization-Ostwald ripening” growth mechanism has been proposed. The electro-chemical performance of h-WO3 nanoflakes has also been investigated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). It is found that h-WO3 modified glassy carbon electrode (GCE) showed lower charge transfer resistance and enhancement in peak current attributed to the enrichment in electroactive surface area and faster electron transfer kinetics at h-WO3 modified GCE.</p>

Improvement of Ti/RuO2–IrO2 Anode Lifetime and Electrocatalytical Properties by Using an Eco-Friendly Thermal Decomposition Method Using Polyvinyl Alcohol as Solvent

2019 ◽  
Author(s):  
Charlys Bezerra ◽  
Géssica Santos ◽  
Marilia Pupo ◽  
Maria Gomes ◽  
Ronaldo Silva ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Polyvinyl Alcohol ◽  
High Efficiency ◽  
Electrochemical Impedance ◽  
Pechini Method ◽  
Low Cost ◽  
Charge Transfer Resistance ◽  
Transfer Resistance ◽  
Calcination Temperatures ◽  
Service Lifetime

<p>Electrochemical oxidation processes are promising solutions for wastewater treatment due to their high efficiency, easy control and versatility. Mixed metal oxides (MMO) anodes are particularly attractive due to their low cost and specific catalytic properties. Here, we propose an innovative thermal decomposition methodology using <a>polyvinyl alcohol (PVA)</a> as a solvent to prepare Ti/RuO<sub>2</sub>–IrO<sub>2</sub> anodes. Comparative anodes were prepared by conventional method employing a polymeric precursor solvent (Pechini method). The calcination temperatures studied were 300, 400 and 500 °C. The physical characterisation of all materials was performed by X-ray diffraction and scanning electron microscopy coupled with energy dispersive spectroscopy, while electrochemical characterisation was done by cyclic voltammetry, accelerated service lifetime and electrochemical impedance spectroscopy. Both RuO<sub>2</sub> and IrO<sub>2</sub> have rutile-type structures for all anodes. Rougher and more compact surfaces are formed for the anodes prepared using PVA. Amongst temperatures studied, 300 °C using PVA as solvent is the most suitable one to produce anodes with expressive increase in voltammetric charge (250%) and accelerated service lifetime (4.3 times longer) besides reducing charge-transfer resistance (8 times lower). Moreover, the electrocatalytic activity of the anodes synthesised with PVA toward the Reactive Blue 21 dye removal in chloride medium (100 % in 30 min) is higher than that prepared by Pechini method (60 min). Additionally, the removal total organic carbon point out improved mineralisation potential of PVA anodes. Finally, this study reports a novel methodology using PVA as solvent to synthesise Ti/RuO<sub>2</sub>–IrO<sub>2</sub> anodes with improved properties that can be further extended to synthesise other MMO compositions.</p>

scholarly journals Electrochemical Immunosensor for the Quantification of S100B at Clinically Relevant Levels Using a Cysteamine Modified Surface

Sensors ◽  
2021 ◽  
Vol 21 (6) ◽  
pp. 1929
Author(s):  
Alexander Rodríguez ◽  
Francisco Burgos-Flórez ◽  
José D. Posada ◽  
Eliana Cervera ◽  
Valtencir Zucolotto ◽  
...  
Keyword(s):  
Frequency Analysis ◽  
Surface Characterization ◽  
Electrochemical Impedance ◽  
Limit Of Detection ◽  
Neuronal Damage ◽  
Charge Transfer Resistance ◽  
Single Frequency ◽  
Response Analysis ◽  
Transfer Resistance ◽  
Therapeutic Decisions

Neuronal damage secondary to traumatic brain injury (TBI) is a rapidly evolving condition, which requires therapeutic decisions based on the timely identification of clinical deterioration. Changes in S100B biomarker levels are associated with TBI severity and patient outcome. The S100B quantification is often difficult since standard immunoassays are time-consuming, costly, and require extensive expertise. A zero-length cross-linking approach on a cysteamine self-assembled monolayer (SAM) was performed to immobilize anti-S100B monoclonal antibodies onto both planar (AuEs) and interdigitated (AuIDEs) gold electrodes via carbonyl-bond. Surface characterization was performed by atomic force microscopy (AFM) and specular-reflectance FTIR for each functionalization step. Biosensor response was studied using the change in charge-transfer resistance (Rct) from electrochemical impedance spectroscopy (EIS) in potassium ferrocyanide, with [S100B] ranging 10–1000 pg/mL. A single-frequency analysis for capacitances was also performed in AuIDEs. Full factorial designs were applied to assess biosensor sensitivity, specificity, and limit-of-detection (LOD). Higher Rct values were found with increased S100B concentration in both platforms. LODs were 18 pg/mL(AuES) and 6 pg/mL(AuIDEs). AuIDEs provide a simpler manufacturing protocol, with reduced fabrication time and possibly costs, simpler electrochemical response analysis, and could be used for single-frequency analysis for monitoring capacitance changes related to S100B levels.

scholarly journals Influence of HAP on the Morpho-Structural Properties and Corrosion Resistance of ZrO2-Based Composites for Biomedical Applications

Crystals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 202
Author(s):  
Réka Barabás ◽  
Carmen Ioana Fort ◽  
Graziella Liana Turdean ◽  
Liliana Bizo
Keyword(s):  
Electrochemical Impedance ◽  
Artificial Saliva ◽  
Synergetic Effect ◽  
Composite Layer ◽  
Charge Transfer Resistance ◽  
Processing Route ◽  
Dental Alloys ◽  
Metallic Electrode ◽  
Transfer Resistance ◽  
X Ray

In the present work, ZrO2-based composites were prepared by adding different amounts of antibacterial magnesium oxide and bioactive and biocompatible hydroxyapatite (HAP) to the inert zirconia. The composites were synthesized by the conventional ceramic processing route and morpho-structurally analyzed by X-ray powder diffraction (XRPD) and scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDS). Two metallic dental alloys (i.e., Ni–Cr and Co–Cr) coated with a chitosan (Chit) membrane containing the prepared composites were exposed to aerated artificial saliva solutions of different pHs (i.e., 4.3, 5, 6) and the corrosion resistances were investigated by electrochemical impedance spectroscopy technique. The obtained results using the two investigated metallic dental alloys shown quasi-similar anticorrosive properties, having quasi-similar charge transfer resistance, when coated with different ZrO2-based composites. This behavior could be explained by the synergetic effect between the diffusion process through the Chit-composite layer and the roughness of the metallic electrode surface.

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