scholarly journals Electrochemical Analysis of Architecturally Enhanced Life0.5Mn0.5PO4 Multi-Walled Carbon Nanotube Composite

2021 ◽  
Vol 66 ◽  
pp. 1-11
Author(s):  
Sabelo Sifuba ◽  
Shane Willenberg ◽  
Usisipho Feleni ◽  
Natasha Ross ◽  
Emmanuel Iwuoha
Keyword(s):  
Electron Transfer ◽  
Carbon Nanotube ◽  
Electrode Materials ◽  
Electrochemical Impedance ◽  
Electrochemical Analysis ◽  
Spectroscopic Techniques ◽  
Redox Potentials ◽  
Manganese Phosphate ◽  
Multi Walled Carbon Nanotube ◽  
Iron Manganese

In this work, the effect of carbon on the electrochemical properties of multi-walled carbon nanotube (MWCNT) functionalized Lithium iron manganese phosphate was studied. In an attempt to provide insight into the structural and electronic properties of optimized electrode materials a systematic study based on a combination of structural and spectroscopic techniques. The phosphor-olivine LiFe0.5Mn0.5PO4, was synthesized via a simple microwave synthesis using LiFePO4 and LiMnPO4 as precursors. Cyclic voltammetry was used to evaluate the electrochemical parameters (electron transfer and ionic diffusivity) of the LiFe0.5Mn0.5PO4 redox couples. The redox potentials show two separate distinct redox peaks that correspond to Mn2+/Mn3+ (4.1 V vs Li/Li+) and Fe2+/Fe3+ (3.5 V vs Li/Li+) due to interaction arrangement of Fe-O-Mn in the olivine lattice. The electrochemical impedance spectroscopy (EIS) results showed LiFe0.5Mn0.5PO4-MWCNTs having high conductivity with reduced charge resistance. This result demonstrates that MWCNTs stimulates faster electron transfer and stability for the LiFe0.5Mn0.5PO4 framework, which demonstrates favorable as a host material for Li+ ions.

scholarly journals Electrochemical Analysis of Architecturally Enhanced LiFe0.5Mn0.5PO4 Multiwalled Carbon Nanotube Composite

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Sabelo Sifuba ◽  
Shane Willenberg ◽  
Usisipho Feleni ◽  
Natasha Ross ◽  
Emmanuel Iwuoha
Keyword(s):  
Electron Transfer ◽  
Carbon Nanotube ◽  
Electrode Materials ◽  
Electrochemical Impedance ◽  
Electrochemical Analysis ◽  
Multiwalled Carbon Nanotube ◽  
Spectroscopic Techniques ◽  
Redox Potentials ◽  
Multiwalled Carbon ◽  
Iron Manganese

In this work, the effect of carbon on the electrochemical properties of multiwalled carbon nanotube (MWCNT) functionalized lithium iron manganese phosphate was studied. In an attempt to provide insight into the structural and electronic properties of optimized electrode materials, a systematic study based on a combination of structural and spectroscopic techniques was conducted. The phosphor-olivine LiFe0.5Mn0.5PO4 was synthesized via a simple microwave synthesis using LiFePO4 and LiMnPO4 as precursors. Cyclic voltammetry was used to evaluate the electrochemical parameters (electron transfer and ionic diffusivity) of the LiFe0.5Mn0.5PO4 redox couples. The redox potentials show two separate distinct redox peaks that correspond to Mn2+/Mn3+ (4.1 V vs Li/Li+) and Fe2+/Fe3+ (3.5 V vs Li/Li+) due to interaction arrangement of Fe-O-Mn in the olivine lattice. The electrochemical impedance spectroscopy (EIS) results showed LiFe0.5Mn0.5PO4-MWCNTs have high conductivity with reduced charge resistance. This result demonstrates that MWCNTs stimulate faster electron transfer and stability for the LiFe0.5Mn0.5PO4 framework, which demonstrates to be favorable as a host material for Li+ ions.

scholarly journals Insight to Microbial Fe(III) Reduction Mediated by Redox-Active Humic Acids with Varied Redox Potentials

2021 ◽  
Vol 18 (13) ◽  
pp. 6807
Author(s):  
Jingtao Duan ◽  
Zhiyuan Xu ◽  
Zhen Yang ◽  
Jie Jiang
Keyword(s):  
Molecular Weight ◽  
Electron Transfer ◽  
Humic Acids ◽  
Weight Fraction ◽  
Electrochemical Analysis ◽  
Microbial Reduction ◽  
Redox Potentials ◽  
Groundwater Environment ◽  
Redox Active ◽  
Different Molecular Weight

Redox-active humic acids (HA) are ubiquitous in terrestrial and aquatic systems and are involved in numerous electron transfer reactions affecting biogeochemical processes and fates of pollutants in soil environments. Redox-active contaminants are trapped in soil micropores (<2 nm) that have limited access to microbes and HA. Therefore, the contaminants whose molecular structure and properties are not damaged accumulate in the soil micropores and become potential pollution sources. Electron transfer capacities (ETC) of HA reflecting redox activities of low molecular weight fraction (LMWF, <2.5) HA can be detected by an electrochemical method, which is related to redox potentials (Eh) in soil and aquatic environments. Nevertheless, electron accepting capacities (EAC) and electron donating capacities (EDC) of these LMWF HA at different Eh are still unknown. EDC and EAC of different molecular weight HA at different Eh were analyzed using electrochemical methods. EAC of LMWF at −0.59 V was 12 times higher than that at −0.49 V, while EAC increased to 2.6 times when the Eh decreased from −0.59 V to −0.69 V. Afterward, LMWF can act as a shuttle to stimulate microbial Fe(III) reduction processes in microbial reduction experiments. Additionally, EAC by electrochemical analysis at a range of −0.49–−0.59 V was comparable to total calculated ETC of different molecular weight fractions of HA by microbial reduction. Therefore, it is indicated that redox-active functional groups that can be reduced at Eh range of −0.49–−0.59 are available to microbial reduction. This finding contributes to a novel perspective in the protection and remediation of the groundwater environment in the biogeochemistry process.

Wood derived biochar as electron donor and its influence on microbial denitrification: Role of extracellular polymeric substances in extracellular electron transfer

2020 ◽  
Author(s):  
Kuppusamy Sathishkumar ◽  
Yi Li ◽  
Rana Muhammad Adnan Ikram
Keyword(s):  
Electron Transfer ◽  
Electron Donor ◽  
Electrochemical Behavior ◽  
Nitrate Reduction ◽  
Extracellular Polymeric Substances ◽  
Electrochemical Impedance ◽  
Electrochemical Analysis ◽  
Extracellular Electron Transfer ◽  
Microbial Denitrification

&lt;p&gt;Biochar is extensively used in environmental pollutant remediation because of its diverse property, however the effect of biochar on microbial nitrate reduction and electrochemical behavior of biochar remain unknown. Also electron transfer from the microbial cells to electron donor or acceptor have been transport across the extracellular polymeric substances (EPS), however it was unclear whether extracellular polymeric substances captured or enhance the electrons.&amp;#160; Hence, aim of the present study is to investigate the electrochemical behavior of biochar and its effects on microbial nitrate reduction and elucidate the role of extracellular polymeric substances in extracellular electron transfer (EET).&amp;#160; The biochar was prepared at different pyrolysis temperatures (400 &amp;#176;C, 500 &amp;#176;C and 600 &amp;#176;C) and their electrochemical behavior was characterized by electrochemical analysis (cyclic voltammetry, electrochemical impedance spectrum, chronoamperometry). Results demonstrated that all the biochars could donate and accept the electrons, impact of biochar on microbial nitrate reduction was studied and the results showed that biochar prepared at 400 &amp;#176;C significantly enhances microbial nitrate reduction process. Phenol O-H and quinone C=O surface functional groups on the biochar contributes in the overall electron exchange which accelerated the nitrate reduction. The role of EPS in EET by electrochemical analysis results reveals that outer membrane c-type cytochrome and flavin protein from the biofilm was involved in electron transfer process, and EPS act as transient media for microbial EET. Overall, present study suggested that biochar could be used as eco-friendly material for the enhancement of microbial denitrification.&lt;/p&gt;

scholarly journals Electroactive graphene-multi-walled carbon nanotube hybrid supported impedimetric immunosensor for the detection of human cardiac troponin-I

RSC Advances ◽  
2015 ◽  
Vol 5 (92) ◽  
pp. 74994-75003 ◽  
Author(s):  
Shobhita Singal ◽  
Avanish K. Srivastava ◽  
Sanjay Dhakate ◽  
Ashok M. Biradar ◽  
Rajesh Rajesh
Keyword(s):  
Carbon Nanotube ◽  
Glassy Carbon ◽  
Cardiac Troponin ◽  
Troponin I ◽  
Electrochemical Impedance ◽  
Three Dimensional ◽  
Carbon Electrode ◽  
Multi Walled Carbon Nanotube ◽  
Impedimetric Immunosensor ◽  
Impedance Immunosensor

We report a sensitive and stable electrochemical impedance immunosensor prepared with electroactive three-dimensional graphene-multi-walled carbon nanotube hybrid deposited on a glassy carbon electrode.

Polymer-Clay Nanocomposites as Precursors of Nanostructured Carbon Materials for Electrochemical Devices: Templating Effect of Clays

2008 ◽  
Vol 8 (4) ◽  
pp. 1741-1750 ◽  
Author(s):  
Rocío Fernández-Saavedra ◽  
Margarita Darder ◽  
Almudena Gómez-Avilés ◽  
Pilar Aranda ◽  
Eduardo Ruiz-Hitzky
Keyword(s):  
Clay Minerals ◽  
Electrode Materials ◽  
Electrochemical Sensors ◽  
Electrochemical Impedance ◽  
Thermal Transformation ◽  
Clay Nanocomposites ◽  
Spectroscopic Techniques ◽  
Electrochemical Devices ◽  
Analytical Tools

The present work introduces a comparative study on the use of polymer nanocomposites containing clay minerals of different structure, such as montmorillonite and sepiolite as host solids for the templating synthesis of carbon-like materials from different organic precursors. Carbon-clay nanocomposites were obtained by polymerization of either acrylonitrile or sucrose previously inserted in the pores of the clay minerals, followed by their further thermal transformation in carbon-like compounds. Acid treatment of the resulting carbon-clay nanocomposites removes the inorganic templates giving carbon-like materials with different textural features. Polymer-clay, carbon-clay and carbon-like materials have been characterized by applying spectroscopic techniques as FTIR and in situ EIS (electrochemical impedance spectroscopy) and other structural, textural and analytical tools (chemical analysis, XRD, SEM-EDX, TEM-EDX, N2 adsorption isotherms,...). Electrochemical properties of these carbon-clay nanocomposites, as well as their templated carbonaceous materials and their use as electrode materials of different electrochemical devices such as rechargeable Li-batteries, supercapacitors and electrochemical sensors, are also discussed.

scholarly journals Promoting of direct electron transfer of multicopper oxidase by control of enzyme molecule density on multi-walled carbon nanotube

2020 ◽  
Vol 3 (1) ◽  
pp. 014006
Author(s):  
Eiichiro Takamura ◽  
Taku Ohnishi ◽  
Hiroaki Sakamoto ◽  
Takenori Satomura ◽  
Shin-ichiro Suye
Keyword(s):  
Electron Transfer ◽  
Carbon Nanotube ◽  
Direct Electron Transfer ◽  
Multicopper Oxidase ◽  
Enzyme Molecule ◽  
Multi Walled Carbon Nanotube

scholarly journals Carbon Nanotube Yarn Microelectrodes Promote High Temporal Measurements of Serotonin Using Fast Scan Cyclic Voltammetry

Sensors ◽  
2020 ◽  
Vol 20 (4) ◽  
pp. 1173 ◽  
Author(s):  
Alexander Mendoza ◽  
Thomas Asrat ◽  
Favian Liu ◽  
Pauline Wonnenberg ◽  
Alexander G. Zestos
Keyword(s):  
Electron Transfer ◽  
Cyclic Voltammetry ◽  
Carbon Nanotube ◽  
Electrode Materials ◽  
Cyclic Voltammograms ◽  
Electron Transfer Kinetics ◽  
Fast Scan Cyclic Voltammetry ◽  
Peak Separation ◽  
Aspect Ratios ◽  
Carbon Fiber Microelectrodes

Carbon fiber-microelectrodes (CFMEs) have been the standard for neurotransmitter detection for over forty years. However, in recent years, there have been many advances of utilizing alternative nanomaterials for neurotransmitter detection with fast scan cyclic voltammetry (FSCV). Recently, carbon nanotube (CNT) yarns have been developed as the working electrode materials for neurotransmitter sensing capabilities with fast scan cyclic voltammetry. Carbon nanotubes are ideal for neurotransmitter detection because they have higher aspect ratios enabling monoamine adsorption and lower limits of detection, faster electron transfer kinetics, and a resistance to surface fouling. Several methods to modify CFMEs with CNTs have resulted in increases in sensitivity, but have also increased noise and led to irreproducible results. In this study, we utilize commercially available CNT-yarns to make microelectrodes as enhanced neurotransmitter sensors for neurotransmitters such as serotonin. CNT-yarn microelectrodes have significantly higher sensitivities (peak oxidative currents of the cyclic voltammograms) than CFMEs and faster electron transfer kinetics as measured by peak separation (ΔEP) values. Moreover, both serotonin and dopamine are adsorption controlled to the surface of the electrode as measured by scan rate and concentration experiments. CNT yarn microelectrodes also resisted surface fouling of serotonin onto the surface of the electrode over thirty minutes and had a wave application frequency independent response to sensitivity at the surface of the electrode.

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