scholarly journals Electrochemiluminescence at 3D Printed Titanium Electrodes

2021 ◽  
Vol 9 ◽  
Author(s):  
Samantha F. Douman ◽  
Miren Ruiz De Eguilaz ◽  
Loanda R. Cumba ◽  
Stephen Beirne ◽  
Gordon G. Wallace ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Electrode Array ◽  
Active Surface ◽  
Active Surface Area ◽  
Linear Diffusion ◽  
Titanium Electrode ◽  
Heterogeneous Electron Transfer ◽  
A Value ◽  
3D Printed ◽  
The Individual

The fabrication and electrochemical properties of a 3D printed titanium electrode array are described. The array comprises 25 round cylinders (0.015 cm radius, 0.3 cm high) that are evenly separated on a 0.48 × 0.48 cm square porous base (total geometric area of 1.32 cm2). The electrochemically active surface area consists of fused titanium particles and exhibits a large roughness factor ≈17. In acidic, oxygenated solution, the available potential window is from ~-0.3 to +1.2 V. The voltammetric response of ferrocyanide is quasi-reversible arising from slow heterogeneous electron transfer due to the presence of a native/oxidatively formed oxide. Unlike other metal electrodes, both [Ru(bpy)3]1+ and [Ru(bpy)3]3+ can be created in aqueous solutions which enables electrochemiluminescence to be generated by an annihilation mechanism. Depositing a thin gold layer significantly increases the standard heterogeneous electron transfer rate constant, ko, by a factor of ~80 to a value of 8.0 ± 0.4 × 10−3 cm s−1 and the voltammetry of ferrocyanide becomes reversible. The titanium and gold coated arrays generate electrochemiluminescence using tri-propyl amine as a co-reactant. However, the intensity of the gold-coated array is between 30 (high scan rate) and 100-fold (slow scan rates) higher at the gold coated arrays. Moreover, while the voltammetry of the luminophore is dominated by semi-infinite linear diffusion, the ECL response is significantly influenced by radial diffusion to the individual microcylinders of the array.

scholarly journals A method for image-guided positioning of cochlear specimens in insertion test benches using 3D printed stands

2021 ◽  
Vol 7 (2) ◽  
pp. 105-108
Author(s):  
Thomas S. Rau ◽  
Jakob Cramer ◽  
M. Geraldine Zuniga ◽  
Georg Böttcher ◽  
Thomas Lenarz
Keyword(s):  
Ex Vivo ◽  
Electrode Array ◽  
Force Sensor ◽  
Rigid Fixation ◽  
Image Guided ◽  
Specimen Holder ◽  
Individual Specimen ◽  
3D Printed ◽  
Parametric Cad ◽  
The Individual

Abstract Cochlear implants include an electrode array (EA) which needs to be inserted into the cochlea. Insertion tests using artificial cochlear models (ACM) or ex vivo specimens are widely used methods during EA development to characterize EA design properties, including insertion forces. Measured forces are directly linked to the orientation of the cochlear lumen with respect to the insertion axis of the test bench. While desired insertion directions in ACM experiments can be predefined by design, specimens are individually shaped and the cochlear lumen is embedded invisibly. Therefore, a new method for accurate, individual specimen positioning is required. A key element of the proposed method is a customizable pose setting adapter (PSA) used to adjust the specimen’s fine positioning. After rigid fixation of the specimen to a holder featuring spherical registration markers and subsequent cone beam computed tomography the desired insertion direction is planned. The planned data is used to calculate the individual shape of the PSA. Finally, the PSA is 3D printed and mounted between force sensor and specimen holder to correctly align the specimen to the test bench’s insertion axis. All necessary hard- and software have been developed including the specimen holder, a software for registration and trajectory planning, and a custom Matlab script whose output drives a parametric CAD file of the PSA. Positioning accuracy was determined in a first trial using 10 virtual trajectories and was found to be 0.23 ± 0.12 mm and 0.38 ± 0.17°. The presented stereotactic positioning procedure enables high repeatability in future ex vivo insertion experiments due to accurate, image-guided control of the insertion direction.

High loading accessible active sites via designable 3D-printed metal architecture towards promoting electrocatalytic performance

2019 ◽  
Vol 7 (31) ◽  
pp. 18338-18347 ◽  
Author(s):  
Shuai Chang ◽  
Xiaolei Huang ◽  
Chun Yee Aaron Ong ◽  
Liping Zhao ◽  
Liqun Li ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
3D Printing ◽  
Surface Area ◽  
Active Sites ◽  
Active Surface ◽  
Catalyst Loading ◽  
Active Surface Area ◽  
Electrochemically Active ◽  
3D Printed ◽  
Electrochemically Active Surface

3D printing of a tailor-designed support architecture with a tunable electrochemically active surface area for improving catalyst loading contributions to catalytic activity.

scholarly journals The electrochemical properties of carbon nanotubes and carbon XC-72R and their application as Pt supports§

2010 ◽  
Vol 75 (10) ◽  
pp. 1435-1439 ◽  
Author(s):  
Maja Obradovic
Keyword(s):  
Carbon Nanotubes ◽  
Electron Transfer ◽  
Electrochemical Properties ◽  
Surface Area ◽  
Carbon Materials ◽  
Active Surface ◽  
Active Surface Area ◽  
Electron Transfer Kinetics ◽  
Electrochemically Active ◽  
Electrochemically Active Surface

The results of an investigation of two samples of commercial multi-walled carbon nanotubes and a sample of carbon black, in the raw and activated state, were presented in the lecture. The activation of the carbon materials led to the formation of an abundance of oxygencontaining functional groups on the surface, an increased electrochemically active surface area, an enhanced charge storage ability and a promotion of the electron-transfer kinetics. It was presented that the morphology of the carbon nanotubes is important for the electrochemical properties, because nanotubes with a higher proportion of edge and defect sites showed faster electron transfer and pseudocapacitive redox kinetics. Modification of oxidized nanotubes by ethylenediamine and wrapping by poly(diallyldimethylammonium) chloride led to a decrease in the electrochemically active surface area and to reduced electron-transfer kinetics. Pt nanoparticles prepared by the microwave-assisted polyol method were deposited at the investigated carbon materials. A much higher efficiency of Pt deposition was observed on the modified CNTs than on the activated CNTs. The activity of the synthesized catalyst toward electrochemical oxygen reduction was almost the same as the activity of the commercial Pt/XC-72 catalyst.

scholarly journals Electron Transfer of Myoglobin Immobilized in Au Electrodes Modified with a RAFT PMMA-Block-PDMAEMA Polymer

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Carla N. Toledo ◽  
Fábio H. Florenzano ◽  
José M. Schneedorf
Keyword(s):  
Electron Transfer ◽  
Chain Transfer ◽  
Reduction Potential ◽  
Hydrophobic Interactions ◽  
Cyclic Voltammograms ◽  
Redox Center ◽  
Heterogeneous Electron Transfer ◽  
A Value ◽  
Reversible Addition ◽  
Raft Polymers

Myoglobin was immobilized with poly(methyl methacrylate)-block-poly[(2-dimethylamino)ethyl methacrylate]PMMA-block-PDMAEMA polymer synthesized by reversible addition-fragmentation chain transfer technique (RAFT). Cyclic voltammograms gave direct and slow quasireversible heterogeneous electron transfer kinetics between Mb-PMMA-block-PDMAEMA modified electrode and the redox center of the protein. The values for electron rate constant (Ks) and transfer coefficient (α) were0.055±0.01·s−1and0.81±0.08, respectively. The reduction potential determined as a function of temperature (293–328 K) revealed a value of reaction center entropy ofΔS0of351.3±0.0002 J·mol−1·K−1and enthalpy change of-76.8±0.1 kJ·mol−1, suggesting solvent effects and charge ionization atmosphere involved in the reaction parallel to hydrophobic interactions with the copolymer. The immobilized protein also exhibits an electrocatalytical response to reduction of hydrogen peroxide, with an apparentKmof114.7±58.7 μM. The overall results substantiate the design and use of RAFT polymers towards the development of third-generation biosensors.

Highly sensitive electrochemical sensor for toxic ractopamine based on the enhancement effect of acetylene black nanoparticles

2015 ◽  
Vol 7 (19) ◽  
pp. 8069-8077 ◽  
Author(s):  
Rui Wang ◽  
Kangbing Wu ◽  
Can Wu
Keyword(s):  
Electron Transfer ◽  
Electrochemical Sensor ◽  
Active Surface ◽  
Acetylene Black ◽  
Enhancement Effect ◽  
Active Surface Area ◽  
Carbon Electrode ◽  
Modified Glassy Carbon Electrode ◽  
Highly Sensitive ◽  
Electron Transfer Capacity

A highly sensitive electrochemical sensor for toxic ractopamine was developed using an acetylene black nanoparticle-modified glassy carbon electrode, exhibiting a large active surface area and enhanced electron transfer capacity.

The Students Value Attitude to Healthy Lifestyle

2019 ◽  
Vol 9 (4) ◽  
pp. 66-70
Author(s):  
Marina Anatolevna Mefodeva ◽  
Gulnara Firdusovna Valieva
Keyword(s):  
Healthy Lifestyle ◽  
Educational Institutions ◽  
A Value ◽  
The Individual

Abstract The relevance of the investigated problem is caused by the increased attention to the issues of a healthy lifestyle among students in Russia. Promotion of a healthy lifestyle, taking into account the individual interests and preferences of students can be embodied not only in the class but also in the framework of elective programs and courses, that are targeted on a healthy lifestyle. The authors reveal approaches, principles and pedagogical conditions for having a healthy lifestyle in the framework of training in educational institutions. The issues of bad habits influence the development and formation of a value attitude to a healthy lifestyle are considered.

Tenacious Mass Transfer Limitations Drive Catalytic Selectivity during Electrochemical Carbon Dioxide Reduction

2019 ◽  
Author(s):  
Kailun Yang ◽  
Recep Kas ◽  
Wilson A. Smith
Keyword(s):  
Surface Area ◽  
High Surface ◽  
High Surface Area ◽  
Catalyst Layer ◽  
Active Surface ◽  
Active Surface Area ◽  
High Concentration ◽  
Copper Electrodes ◽  
Surface Enhanced ◽  
Local Current

<p>This study evaluated the performance of the commonly used strong buffer electrolytes, i.e. phosphate buffers, during CO<sub>2</sub> electroreduction in neutral pH conditions by using in-situ surface enhanced infrared absorption spectroscopy (SEIRAS). Unfortunately, the buffers break down a lot faster than anticipated which has serious implications on many studies in the literature such as selectivity and kinetic analysis of the electrocatalysts. Increasing electrolyte concentration, surprisingly, did not extend the potential window of the phosphate buffers due to dramatic increase in hydrogen evolution reaction. Even high concentration phosphate buffers (1 M) break down within the potentials (-1 V vs RHE) where hydrocarbons are formed on copper electrodes. We have extended the discussion to high surface area electrodes by evaluating electrodes composed of copper nanowires. We would like highlight that it is not possible to cope with high local current densities on these high surface area electrodes by using high buffer capacity solutions and the CO<sub>2</sub> electrocatalysts are needed to be evaluated by casting thin nanoparticle films onto inert substrates as commonly employed in fuel cell reactions and up to now scarcely employed in CO<sub>2</sub> electroreduction. In addition, we underscore that normalization of the electrocatalytic activity to the electrochemical active surface area is not the ultimate solution due to concentration gradient along the catalyst layer.This will “underestimate” the activity of high surface electrocatalyst and the degree of underestimation will depend on the thickness, porosity and morphology of the catalyst layer. </p> <p> </p>

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