Immobilization of bilirubin oxidase on graphene oxide flakes with different negative charge density for oxygen reduction. The effect of GO charge density on enzyme coverage, electron transfer rate and current density

2017 ◽  
Vol 89 ◽  
pp. 384-389 ◽  
Author(s):  
Jaroslav Filip ◽  
Anita Andicsová-Eckstein ◽  
Alica Vikartovská ◽  
Jan Tkac
Keyword(s):  
Electron Transfer ◽  
Graphene Oxide ◽  
Charge Density ◽  
Oxygen Reduction ◽  
Current Density ◽  
Transfer Rate ◽  
Negative Charge ◽  
Electron Transfer Rate ◽  
Bilirubin Oxidase ◽  
Negative Charge Density

scholarly journals Impact of Surface Modification with Gold Nanoparticles on the Bioelectrocatalytic Parameters of Immobilized Bilirubin Oxidase

Acta Naturae ◽  
2014 ◽  
Vol 6 (1) ◽  
pp. 102-106 ◽  
Author(s):  
D. V. Pankratov ◽  
Y. S. Zeifman ◽  
А. V. Dudareva ◽  
G. K. Pankratova ◽  
M. E. Khlupova ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Electron Transfer ◽  
Transfer Rate ◽  
Direct Electron Transfer ◽  
Electron Transfer Rate ◽  
Bilirubin Oxidase ◽  
Heterogeneous Electron Transfer ◽  
Enzyme Molecules ◽  
Different Diameters ◽  
The Impact

We unveil experimental evidence that put into question the widely held notion concerning the impact of nanoparticles on the bioelectrocatalytic parameters of enzymatic electrodes. Comparative studies of the bioelectrocatalytic properties of fungal bilirubin oxidase from Myrothecium verrucaria adsorbed on gold electrodes, modified with gold nanoparticles of different diameters, clearly indicate that neither the direct electron transfer rate (standard heterogeneous electron transfer rate constants were calculated to be 319 s -1) nor the biocatalytic activity of the adsorbed enzyme (bioelectrocatalytic constants were calculated to be 3411 s -1) depends on the size of the nanoparticles, which had diameters close to or larger than those of the enzyme molecules.

3D structured Mn2O3 synthesized using tween surfactant: influence on the morphology and oxygen reduction catalytic performance

CrystEngComm ◽  
2019 ◽  
Vol 21 (3) ◽  
pp. 420-429 ◽  
Author(s):  
Yuan Fang ◽  
Yonghui Wang ◽  
Fen Wang ◽  
Jianfeng Zhu
Keyword(s):  
Electron Transfer ◽  
Oxygen Reduction ◽  
Transfer Rate ◽  
Oxygen Vacancies ◽  
Tween 80 ◽  
Catalytic Performance ◽  
Oxygen Storage ◽  
Electron Transfer Rate

Tween-80 affects the oxygen vacancies of Mn2O3, boosting its oxygen storage capability and electron transfer rate for ORR.

scholarly journals Enhancement of Electrochemical Performance of Bilirubin Oxidase Modified Gas Diffusion Biocathode by Porphyrin Precursor

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Erica Pinchon ◽  
Mary Arugula ◽  
Kapil Pant ◽  
Sameer Singhal
Keyword(s):  
Electron Transfer ◽  
Oxygen Reduction ◽  
Power Density ◽  
Current Density ◽  
Direct Electron Transfer ◽  
Glucose Dehydrogenase ◽  
Phosphate Buffer Solution ◽  
Gas Diffusion ◽  
Biofuel Cell ◽  
Bilirubin Oxidase

Recent studies have focused on tailoring the catalytic currents of multicopper oxidase (MCO) enzymes-based biocathodes to enhance oxygen reduction. Biocathodes modified with natural substrates specific for MCO enzymes demonstrated drastic improvement for oxygen reduction. Performance of 1-pyrenebutanoic acid, succinimidyl ester (PBSE), and 2,5-dimethyl-1-phenyl-1H-pyrrole-3-carbaldehyde (Di-Carb) oriented bilirubin oxidase (BOx) modified gas diffusion biocathode has been highly improved by incorporating hematin, a porphyrin precursor as electron transfer enhancement moiety. Hematin modified electrodes demonstrated direct electron transfer reaction of BOx exhibiting larger O2 reduction in current density in phosphate buffer solution (pH 7.0) without the need of a mediator. A remarkable improvement in the catalytic currents with 2.5-fold increase compared to non-hematin modified oriented BOx electrodes was achieved. Moreover, a mediatorless and compartmentless glucose/O2 biofuel cell based on DET-type bioelectrocatalysis via the BOx cathode and the glucose dehydrogenase (GDH) anode demonstrated peak power densities of 1 mW/cm2 at pH 7.0 with 100 mM glucose/10 mM NAD fuel. The maximum current density of 1.6 mA/cm2 and the maximum power density of 0.4 mW/cm2 were achieved at 300 mV with nonmodified BOx cathode, while 3.5 mA/cm2 and 1.1 mW/cm2 of current and power density were achieved with hematin modified cathode. The performance improved 2.4 times which attributes to the hematin acting as a natural precursor and activator for BOx activity enhancement.

scholarly journals Comparison of Electrode Reduction Activities of Geobacter sulfurreducens and an Enriched Consortium in an Air-Cathode Microbial Fuel Cell

2008 ◽  
Vol 74 (23) ◽  
pp. 7348-7355 ◽  
Author(s):  
Shun'ichi Ishii ◽  
Kazuya Watanabe ◽  
Soichi Yabuki ◽  
Bruce E. Logan ◽  
Yuji Sekiguchi
Keyword(s):  
Electron Transfer ◽  
Fuel Cell ◽  
Microbial Fuel Cell ◽  
Current Density ◽  
Transfer Rate ◽  
Geobacter Sulfurreducens ◽  
Electron Transfer Rate ◽  
Air Cathode ◽  
Anodic Reaction ◽  
Density And Biomass

ABSTRACT An electricity-generating bacterium, Geobacter sulfurreducens PCA, was inoculated into a single-chamber, air-cathode microbial fuel cell (MFC) in order to determine the maximum electron transfer rate from bacteria to the anode. To create anodic reaction-limiting conditions, where electron transfer from bacteria to the anode is the rate-limiting step, anodes with electrogenic biofilms were reduced in size and tests were conducted using anodes of six different sizes. The smallest anode (7 cm2, or 1.5 times larger than the cathode) achieved an anodic reaction-limiting condition as a result of a limited mass of bacteria on the electrode. Under these conditions, the limiting current density reached a maximum of 1,530 mA/m2, and power density reached a maximum of 461 mW/m2. Per-biomass efficiency of the electron transfer rate was constant at 32 fmol cell−1 day−1 (178 μmol g of protein−1 min−1), a rate comparable to that with solid iron as the electron acceptor but lower than rates achieved with fumarate or soluble iron. In comparison, an enriched electricity-generating consortium reached 374 μmol g of protein−1 min−1 under the same conditions, suggesting that the consortium had a much greater capacity for electrode reduction. These results demonstrate that per-biomass electrode reduction rates (calculated by current density and biomass density on the anode) can be used to help make better comparisons of electrogenic activity in MFCs.

Reduced Graphene Oxide-Supported Cobalt Phosphide Nanoflowers via in situ Hydrothermal Synthesis as Pt-Free Effective Electrocatalysts for Oxygen Reduction Reaction

NANO ◽  
2018 ◽  
Vol 13 (05) ◽  
pp. 1850047 ◽  
Author(s):  
Yang Lv ◽  
Xianbao Wang ◽  
Tao Mei ◽  
Jinhua Li ◽  
Jianying Wang
Keyword(s):  
Electron Transfer ◽  
Graphene Oxide ◽  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Reduced Graphene Oxide ◽  
Current Density ◽  
Reduction Reaction ◽  
Cobalt Phosphide ◽  
Reduced Graphene

Cobalt phosphide (CoP) has aroused extensive research interest in a field of electrochemical application due to its excellent catalytic activities. CoP and its compounds have been widely reported using in hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). However, few reports about CoP as electrocatalysts for oxygen reduction reaction (ORR) were presented. In this work, we prepare reduced graphene-oxide(rGO)-loaded CoP (rGO@CoP) as an electrocatalyst for ORR through in situ hydrothermal treatment. The rGO@CoP as ORR catalyst exhibits excellent activities where its onset potential has a positive increase of 129[Formula: see text]mV, and the ORR potential achieves an increase of 330[Formula: see text]mV at a current density of 1.0[Formula: see text]mA[Formula: see text]cm[Formula: see text] compared with that of pure CoP. The current density is also significantly improved with an increase of 0.51[Formula: see text]mA[Formula: see text]cm[Formula: see text] at [Formula: see text]350[Formula: see text]mV, and the Tafel slope has a decrease of 19[Formula: see text]mV dec[Formula: see text]. Further tests show that the electron transfer number of rGO@CoP is 3.66, which is larger than 2.19 of pure CoP, indicating that it is dominated by a four-electron transfer pathway. Moreover, its stability (remained 98.6% current after working 6000[Formula: see text]s) and methanol tolerance are outstanding. These results show that rGO@CoP may be considered to replace traditional Pt-based ORR catalysts for fuel cells, and rGO loading has been proven to be an effective strategy to enhance the ORR performance of CoP, which may provide a new idea to synthesize transition metal phosphides as ORR catalysts.

Tuning the Photocatalytic Performance of Plasmonic Nanocomposites (ZnO/Aux) Driven in Visible Light

2019 ◽  
Vol 8 (1) ◽  
pp. 56-61
Author(s):  
Aneeya K. Samantara ◽  
Debasrita Dash ◽  
Dipti L. Bhuyan ◽  
Namita Dalai ◽  
Bijayalaxmi Jena
Keyword(s):  
Electron Transfer ◽  
Photocatalytic Activity ◽  
Visible Light ◽  
Transfer Rate ◽  
Photocatalytic Performance ◽  
Light Exposure ◽  
Au Nanoparticle ◽  
Electron Transfer Rate ◽  
Au Nps ◽  
Zno Nanostructure

: In this article, we explored the possibility of controlling the reactivity of ZnO nanostructures by modifying its surface with gold nanoparticles (Au NPs). By varying the concentration of Au with different wt% (x = 0.01, 0.05, 0.08, 1 and 2), we have synthesized a series of (ZnO/Aux) nanocomposites (NCs). A thorough investigation of the photocatalytic performance of different wt% of Au NPs on ZnO nanosurface has been carried out. It was observed that ZnO/Au0.08 nanocomposite showed the highest photocatalytic activity among all concentrations of Au on the ZnO surface, which degrades the dye concentration within 2 minutes of visible light exposure. It was further revealed that with an increase in the size of plasmonic nanoparticles beyond 0.08%, the accessible surface area of the Au nanoparticle decreases. The photon absorption capacity of Au nanoparticle decreases beyond 0.08% resulting in a decrease in electron transfer rate from Au to ZnO and a decrease of photocatalytic activity. Background: Due to the industrialization process, most of the toxic materials go into the water bodies, affecting the water and our ecological system. The conventional techniques to remove dyes are expensive and inefficient. Recently, heterogeneous semiconductor materials like TiO2 and ZnO have been regarded as potential candidates for the removal of dye from the water system. Objective: To investigate the photocatalytic performance of different wt% of Au NPs on ZnO nanosurface and the effect of the size of Au NPs for photocatalytic performance in the degradation process. Methods: A facile microwave method has been adopted for the synthesis of ZnO nanostructure followed by a reduction of gold salt in the presence of ZnO nanostructure to form the composite. Results: ZnO/Au0.08 nanocomposite showed the highest photocatalytic activity which degrades the dye concentration within 2 minutes of visible light exposure. The schematic mechanism of electron transfer rate was discussed. Conclusion: Raspberry shaped ZnO nanoparticles modified with different percentages of Au NPs showed good photocatalytic behavior in the degradation of dye molecules. The synergetic effect of unique morphology of ZnO and well anchored Au nanostructures plays a crucial role.

The Single-Molecule Conductance and Electrochemical Electron-Transfer Rate Are Related by a Power Law

ACS Nano ◽  
2013 ◽  
Vol 7 (6) ◽  
pp. 5391-5401 ◽  
Author(s):  
Emil Wierzbinski ◽  
Ravindra Venkatramani ◽  
Kathryn L. Davis ◽  
Silvia Bezer ◽  
Jing Kong ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Single Molecule ◽  
Power Law ◽  
Transfer Rate ◽  
Electron Transfer Rate
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