scholarly journals Enhancing the catalytic current response of H 2 oxidation gas diffusion bioelectrodes using an optimized viologen‐based redox polymer and [NiFe] hydrogenase

2021 ◽  
Author(s):  
Anna Lielpetere ◽  
Jana M. Becker ◽  
Julian Szczesny ◽  
Felipe Conzuelo ◽  
Adrian Ruff ◽  
...  
Keyword(s):  
Gas Diffusion ◽  
Current Response ◽  
Redox Polymer ◽  
Catalytic Current

Catalytic Oxidation of NADH on Gold Electrode Modified by Layer-by- Layer Self-Assembly of Thermostable Diaphorase and Redox Polymer

2011 ◽  
Vol 675-677 ◽  
pp. 231-234 ◽  
Author(s):  
Wen Juan Zheng ◽  
Hai Tao Zheng ◽  
Tao Sun ◽  
Pu Liu ◽  
Shinichiro Suye
Keyword(s):  
Self Assembly ◽  
Multilayer Structure ◽  
Gold Electrode ◽  
Multilayer Film ◽  
Water Soluble ◽  
Current Response ◽  
Layer By Layer ◽  
Redox Polymer ◽  
Relative Response ◽  
Reduced Nicotinamide Adenine Dinucleotide

A redox polymer, poly(ethylenimine)ferrocene (PEI-Fc) was synthesized by attaching ferrocene groups to the backbone of water soluble poly(ethylenimine), and multilayer film in nanoscale was assembled on gold electrode by alternate layer-by-layer adsorption (LBL) of the positively charged PEI-Fc and the negatively charged thermostable diaphorase (DI) from B.Stearothermophilus. The LBL process was monitored and analyzed by quartz crystal microbalance (QCM) technique, which confirmed the formation of the multilayer structure. The electrochemical oxidation of coenzyme (reduced nicotinamide adenine dinucleotide, NADH) was observed on the electrode fabricated with PEI-Fc/DI multilayer film, and the influence of layer number on current response was investigated. The modified electrode retained ca. 65% relative response after storage in buffer for two months and 50% relative response after incubation at 80 °C for 3 min, which inferred that the multilayer structure was unique stable. A NAD-dependent glucose-6-phosphate dehydrogenase (G6PDH) was also immobilized via the same LBL technique, and electrode modified with PEI-Fc/DI/G6PDH film exhibited current response to glucose-6- phosphate in the presence of free NAD+.

scholarly journals High Electric Production by Membraneless Microbial Fuel Cell with Up Flow Operation Using Acetate Wastewater

2020 ◽  
Vol 11 (2) ◽  
pp. 19-27
Author(s):  
Aris Mukimin ◽  
Nur Zen ◽  
Hanny Vistanty ◽  
Purwanto Agus
Keyword(s):  
Fuel Cell ◽  
Microbial Fuel Cell ◽  
Oxygen Demand ◽  
Gas Diffusion ◽  
Synthetic Wastewater ◽  
Anaerobic Sludge ◽  
Carbon Cloth ◽  
Current Response ◽  
Current Voltage ◽  
Anaerobic Chamber

Microbial fuel cell (MFC) is a new proposed technology reported to generate renewable energy while simultaneously treating wastewater. Membraneless microbial fuel cell (ML-MFC) system was developed to eliminate the requirement of membrane which is expensive and prone to clogging while enhancing electricity generation and wastewater treatment efficiency. For this purpose, a reactor was designed in two chambers and connected via three pipes (1 cm in diameter) to enhance fluid diffusion. Influent flowrate was maintained by adjusting peristaltic pump at the base of anaerobic chamber. Carbon cloth (235 cm2) was used as anode and paired with gas diffusion layer (GDL) carbon-Pt as cathode. Anaerobic sludge was filtered and used as starter feed for the anaerobic chamber. The experiment was carried out by feeding synthetic wastewater to anaerobic chamber; while current response and potential were recorded. Performance of reactor was evaluated in terms of chemical oxygen demand (COD). Electroactive microbe was inoculated from anaerobic sludge and showed current response (0.55-0.65 mA) at 0,35 V, range of diameter 1.5-2 µm. The result of microscopics can showed three different species. The microbial performance was increased by adding ferric oxide 1 mM addition as acceptor electron. The reactor was able to generate current, voltage, and electricity power of 0.36 mA, 110 mV, and 40 mWatt (1.5 Watt/m2), respectively, while reaching COD removal and maximum coulomb efficiency (EC) of 16% and 10.18%, respectively.

scholarly journals Stabilization of Bilirubin Oxidase in a Biogel Matrix for High-performance Gas Diffusion Electrodes

2020 ◽  
Author(s):  
Graziela Sedenho ◽  
Ayaz Hassan ◽  
Lucyano Macedo ◽  
Frank Crespilho
Keyword(s):  
Enzyme Immobilization ◽  
Gas Diffusion ◽  
Gas Diffusion Electrodes ◽  
Short Term ◽  
Catalytic Current ◽  
Electron Transfer Mechanism ◽  
Bilirubin Oxidase ◽  
Practical Applications ◽  
Term Stability

Enzyme immobilization on solid conducting surfaces faces some challenges for practical applications in technologies such as biosensors and biofuel cells. Short-term stability, poor electrochemical performance, and enzyme inhibition are some issues that remain unsolved. Here, we propose a simple methodology for bilirubin oxidase (BOD) immobilization on carbon-based gas-diffusion electrodes for a four-electron electrochemical oxygen reduction reaction (ORR). The enzyme is incorporated into a Nafion® polymeric matrix and cross-linked with glutaraldehyde by a one-pot reaction in a buffered solution, producing a stable BOD-based biogel. The biogel prevents the formation of enzyme aggregates, producing a homogeneous bioelectrode surface, and allows access to the direct electron-transfer mechanism of multicopper centers buried in the enzyme. A biocatalytic reduction current of -1.52 ± 0.24 mA cm<sup>-2</sup> at 0.19 ± 0.06 V was observed under gas-diffusion conditions. Additionally, the bioelectrode showed an unprecedented long-term stability under continuous operation combined with satisfactory catalytic current without redox mediator, demonstrating that the BOD-based biogel provides a suitable microenvironment for long-term enzymatic activity involving a bio-three-phase interfacial reaction. Therefore, the present study contributes new insights into enzyme immobilization to overcome the critical short-term stability issue of enzyme-based electrochemical devices for practical applications.

Direct Water Removal in Gas Diffusion Layer of Proton Exchange Membrane Fuel Cells by a Flexible Electroosmotic Pump

2006 ◽  
Author(s):  
S. W. Cha ◽  
T. Fabian ◽  
J. Posner ◽  
C. Buie ◽  
D. J. Kim ◽  
...  
Keyword(s):  
Diffusion Layer ◽  
Proton Exchange Membrane ◽  
Gas Diffusion Layer ◽  
Gas Diffusion ◽  
Proton Exchange ◽  
Limiting Current ◽  
Cathode Side ◽  
Current Response ◽  
Electroosmotic Pump ◽  
Exchange Membrane

An electroosmotic pump is a non-mechanical pump that can remove water by applied electric field. A flexible electroosmotic (EO) pump was directly attached to a gas diffusion layer (GDL) on the cathode side of a miniature proton exchange membrane fuel cell (PEMFC). The operation of EO pump improved the voltage-current response of a PEMFC. Especially, the increase of limiting current was observed. We assume the reduced flooding in GDL was achieved by the operation of EO pump. Further investigation with AC impedance spectroscopy support the assumption as the reduced mass transport resistance was observed.

Electroenzymatic CO2 Fixation Using Redox Polymer/Enzyme-Modified Gas Diffusion Electrodes

2020 ◽  
Vol 5 (1) ◽  
pp. 321-327 ◽  
Author(s):  
Julian Szczesny ◽  
Adrian Ruff ◽  
Ana R. Oliveira ◽  
Marcos Pita ◽  
Inês A. C. Pereira ◽  
...  
Keyword(s):  
Co2 Fixation ◽  
Gas Diffusion ◽  
Gas Diffusion Electrodes ◽  
Redox Polymer

Impedance Spectroscopy Study and System Identification of a Solid-Oxide Fuel Cell Stack With Hammerstein–Wiener Model

2017 ◽  
Vol 14 (2) ◽  
Author(s):  
M. Y. Abdollahzadeh Jamalabadi
Keyword(s):  
Fuel Cell ◽  
Impedance Spectroscopy ◽  
Solid Oxide Fuel Cell ◽  
Electrochemical Impedance ◽  
Gas Diffusion ◽  
Solid Oxide ◽  
Dynamic Responses ◽  
Current Response ◽  
Oxide Fuel ◽  
Wiener Model

In this paper, the electrochemical impedance spectroscopy (EIS) method is applied through a transient in solid oxide fuel cell (SOFC) to obtain the dynamic modeling. Instead of measuring the current response of a fuel cell to a small sinusoidal perturbation in voltage at each frequency, the Hammerstein–Wiener model identification method is applied through a one transient who leads to the significant decrease of computational costs. Dynamic responses are determined as the solutions of coupled partial differential equations derived from conservation laws of charges, mass, momentum, and energy with electrochemical kinetics by using Butler–Volmer model and gas diffusion on the extended Maxwell-Stefan species equations or dusty gas model (DGM). Because the system consisted of electrical and mechanical components, the behavior of the system was nonlinear. The obtained results are in good qualitative agreement with experimental data published in literatures shown the effectiveness of the propose model. Finally, a parametric study based on the obtained model is performed to study the effects of channel length, inlet H2 concentration, inlet velocity, and cell temperature in Nyquist plots and the voltage responses to step changes in the fuel concentration and load current. The model can be useful as a benchmark for illustrating different designs and control schemes.

Electrocatalytic behavior of single walled carbon nanotubes with alkylthio-substituted cobalt binuclear phthalocyanines towards oxidation of 4-chlorophenols

2019 ◽  
Vol 23 (01n02) ◽  
pp. 142-153 ◽  
Author(s):  
Zainab O. Makinde ◽  
Philani Mashazi ◽  
Samson Khene
Keyword(s):  
Carbon Nanotubes ◽  
Modified Electrodes ◽  
Single Walled Carbon Nanotubes ◽  
Carbon Electrodes ◽  
Current Response ◽  
Catalytic Current ◽  
Glassy Carbon Electrodes ◽  
Single Walled Carbon ◽  
Walled Carbon Nanotubes ◽  
Covalent Conjugates

This work describes the adsorption of synthesized cobalt mono (CoPc) and binuclear phthalocyanines (CoBiPc) with single walled carbon nanotubes (SWCNT) to form SWCNT-CoPc or SWCNT-CoBiPc as non-covalent conjugates onto glassy carbon electrodes (GCE). The cobalt complexes and their SWCNT-conjugate-modified electrodes were studied for their electrocatalytic oxidation towards 4-chlorophenol. All modified electrodes showed improved catalytic current and stability towards the detection of 4-chlorophenol. The best activity was observed for the SWCNT-CoBiPc2 system in terms of current response and the SWCNT-CoBiPc1 system in terms of resistance to electrode fouling.

scholarly journals Stabilization of Bilirubin Oxidase in a Biogel Matrix for High-performance Gas Diffusion Electrodes

2020 ◽  
Author(s):  
Graziela Sedenho ◽  
Ayaz Hassan ◽  
Lucyano Macedo ◽  
Frank Crespilho
Keyword(s):  
Enzyme Immobilization ◽  
Gas Diffusion ◽  
Gas Diffusion Electrodes ◽  
Short Term ◽  
Catalytic Current ◽  
Electron Transfer Mechanism ◽  
Bilirubin Oxidase ◽  
Practical Applications ◽  
Term Stability

Enzyme immobilization on solid conducting surfaces faces some challenges for practical applications in technologies such as biosensors and biofuel cells. Short-term stability, poor electrochemical performance, and enzyme inhibition are some issues that remain unsolved. Here, we propose a simple methodology for bilirubin oxidase (BOD) immobilization on carbon-based gas-diffusion electrodes for a four-electron electrochemical oxygen reduction reaction (ORR). The enzyme is incorporated into a Nafion® polymeric matrix and cross-linked with glutaraldehyde by a one-pot reaction in a buffered solution, producing a stable BOD-based biogel. The biogel prevents the formation of enzyme aggregates, producing a homogeneous bioelectrode surface, and allows access to the direct electron-transfer mechanism of multicopper centers buried in the enzyme. A biocatalytic reduction current of -1.52 ± 0.24 mA cm<sup>-2</sup> at 0.19 ± 0.06 V was observed under gas-diffusion conditions. Additionally, the bioelectrode showed an unprecedented long-term stability under continuous operation combined with satisfactory catalytic current without redox mediator, demonstrating that the BOD-based biogel provides a suitable microenvironment for long-term enzymatic activity involving a bio-three-phase interfacial reaction. Therefore, the present study contributes new insights into enzyme immobilization to overcome the critical short-term stability issue of enzyme-based electrochemical devices for practical applications.

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