scholarly journals SYNTHESIS, PHOTO- AND ELECTROCATALYTIC PROPERTIES OF NANOSTRUCTURED Ce–TiO2 FILMS

2019 ◽  
Vol 85 (11) ◽  
pp. 63-72
Author(s):  
Vera Vorobets ◽  
Gennadii Kolbasov ◽  
Svitlana Oblovatna ◽  
Oleg Salamakha ◽  
Sergii Karpenko ◽  
...  
Keyword(s):  
Oxygen Reduction ◽  
Electrode Materials ◽  
Electrochemical Sensors ◽  
Dynamic Range ◽  
Reduction Process ◽  
Oxygen Electroreduction ◽  
Flat Band ◽  
Tio2 Films ◽  
Electrocatalytic Properties ◽  
Photocurrent Spectra

Electrocatalytic films based on nanodispersed titanium dioxide modified by Ce(III) were synthesized by sol-gel method and characterized by X-ray diffraction and ultraviolet-visible photocurrent spectra. The average size of nanoparticles was no more thаn 11 nm. The XRD results indicated that TiO2 and Ce–TiO2 electrodes with Ce concentrations up to 5 % calcined at 500°C consisted of anatase as the unique phase.  The photocurrent spectra of the Ce–TiO2 electrodes (0 ≤ Ce concentration ≤ 2% mol.)  showed a stronger current in the UV range and a shift in the flat-band potential (Еfb) towards more negative values than that of  TiO2 electrodes. Electrocatalytic properties of TiO2 and Ce–TiO2 electrodes were investigated in the process of oxygen electroreduction. It has been found by I–E curves measurements that the potential of oxygen reduction changes with the film composition. Modifying of TiO2 films by Ce(III)  improves catalytic activity of Ce–TiO2 electrodes ( Ce concentration up to 2% mol.)  in the reaction of oxygen electroreduction, that appears in decreasing of oxygen reduction potential EO2 and increasing of dynamic range of O2 electroreduction potentials.  The high electrocatalytic activity of Ce–TiO2 electrodes in the oxygen reduction process may be due to the formation of catalytically active centers which activity may decrease in the presence of an amorphous phase. The correlation between photo- and electrocatalytic properties and structural changes occurring in Ce–TiO2 films on increasing the cerium content is observed.  The electrodes investigated were distinguished by a high sensitivity to dissolved oxygen ((4-5)∙10-6 g·l-1) and high reproducibility of characteristics in long-time cycling. These electrodes promise much as reusable electrode materials in electrochemical sensors for the determination of oxygen in liquids.

scholarly journals Layer-by-layer integration of conducting polymers and metal organic frameworks onto electrode surfaces: enhancement of the oxygen reduction reaction through electrocatalytic nanoarchitectonics

2019 ◽  
Vol 4 (4) ◽  
pp. 893-900 ◽  
Author(s):  
Ana Paula Mártire ◽  
Gustavo M. Segovia ◽  
Omar Azzaroni ◽  
Matías Rafti ◽  
Waldemar Marmisollé
Keyword(s):  
Conducting Polymers ◽  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Electrode Materials ◽  
Metal Organic Frameworks ◽  
Reduction Reaction ◽  
Layer By Layer ◽  
Electrocatalytic Properties ◽  
Electrode Surfaces ◽  
Metal Organic

Nanoarchitectonics can lead to electrode materials with enhanced electrocatalytic properties.

Electrocatalytic properties of nanocomposites based on conducting polymers and titanium dioxide in oxygen reduction process

2012 ◽  
Vol 48 (11) ◽  
pp. 1058-1064 ◽  
Author(s):  
Ya. I. Kurys ◽  
O. S. Dodon ◽  
O. O. Ustavytska ◽  
V. G. Koshechko ◽  
V. D. Pokhodenko
Keyword(s):  
Titanium Dioxide ◽  
Conducting Polymers ◽  
Oxygen Reduction ◽  
Reduction Process ◽  
Electrocatalytic Properties

Polyelectrolyte–single wall carbon nanotube composite as an effective cathode catalyst for air-cathode microbial fuel cells

2014 ◽  
Vol 70 (10) ◽  
pp. 1610-1616 ◽  
Author(s):  
Huanan Wu ◽  
Min Lu ◽  
Lin Guo ◽  
Leonard Guan Hong Bay ◽  
Zheng Zhang ◽  
...  
Keyword(s):  
Fuel Cells ◽  
Carbon Nanotube ◽  
Oxygen Reduction ◽  
Microbial Fuel Cells ◽  
Reduction Process ◽  
Air Cathode ◽  
Single Wall Carbon Nanotube ◽  
Single Wall Carbon ◽  
Cathode Catalysts ◽  
Metal Free

Polyelectrolyte–single wall carbon nanotube (SCNT) composites are prepared by a solution-based method and used as metal-free cathode catalysts for oxygen reduction reaction (ORR) in air-cathode microbial fuel cells (MFCs). In this study, two types of polyelectrolytes, polydiallyldimethylammonium chloride (PDDA) and poly[bis(2-chloroethyl)ether-alt-1,3-bis[3-(dimethylamino)propyl]urea] (PEPU) are applied to decorate the SCNTs and the resulting catalysts exhibit remarkable catalytic ability toward ORR in MFC applications. The enhanced catalytic ability could be attributed to the positively charged quaternary ammonium sites of polyelectrolytes, which increase the oxygen affinity of SCNTs and reduce activation energy in the oxygen reduction process. It is also found that PEPU–SCNT composite-based MFCs show efficient performance with maximum power density of 270.1 mW m−2, comparable to MFCs with the benchmark Pt/C catalyst (375.3 mW m−2), while PDDA–SCNT composite-based MFCs produce 188.9 mW m−2. These results indicate that PEPU–SCNT and PDDA–SCNT catalysts are promising candidates as metal-free cathode catalysts for ORR in MFCs and could facilitate MFC scaling up and commercialization.

scholarly journals Electrostatic self-assembled multilayers of tetrachromatedmetalloporphyrins/polyoxometalateand its electrocatalytic properties in oxygen reduction

2014 ◽  
Vol 146 ◽  
pp. 819-829 ◽  
Author(s):  
Camilo García ◽  
Carlos Díaz ◽  
Paulo Araya ◽  
Fabiola Isaacs ◽  
Guillermo Ferraudi ◽  
...  
Keyword(s):  
Oxygen Reduction ◽  
Electrocatalytic Properties ◽  
Self Assembled

scholarly journals Application of biosynthesized metal nanoparticles in electrochemical sensors

2021 ◽  
pp. 77-77
Author(s):  
Totka Dodevska ◽  
Dobrin Hadzhiev ◽  
Ivan Shterev ◽  
Yanna Lazarova
Keyword(s):  
Green Synthesis ◽  
Metal Nanoparticles ◽  
Electrochemical Sensors ◽  
Dynamic Range ◽  
Limit Of Detection ◽  
Cost Effective ◽  
Electrochemical Sensing ◽  
Synthesis Methods ◽  
Range Limit ◽  
Wide Range

Recently, the development of eco-friendly, cost-effective and reliable methods for synthesis of metal nanoparticles has drawn a considerable attention. The so-called green synthesis, using mild reaction conditions and natural resources as plant extracts and microorganisms, has established as a convenient, sustainable, cheap and environmentally safe approach for synthesis of a wide range of nanomaterials. Over the past decade, biosynthesis is regarded as an important tool for reducing the harmful effects of traditional nanoparticle synthesis methods commonly used in laboratories and industry. This review emphasizes the significance of biosynthesized metal nanoparticles in the field of electrochemical sensing. There is increasing evidence that green synthesis of nanoparticles provides a new direction in designing of cost-effective, highly sensitive and selective electrode-catalysts applicable in food, clinical and environmental analysis. The article is based on 157 references and provided a detailed overview on the main approaches for green synthesis of metal nanoparticles and their applications in designing of electrochemical sensor devices. Important operational characteristics including sensitivity, dynamic range, limit of detection, as well as data on stability and reproducibility of sensors have also been covered. Keywords: biosynthesis; green synthesis; nanomaterials; nanotechnology; modified electrodes

Titania nanotubes coated with graphene as a promising catalyst for the oxygen reduction reaction

2020 ◽  
Vol 44 (18) ◽  
pp. 7417-7423
Author(s):  
Jiannan Cai ◽  
Xiaofeng Zhang ◽  
Yi Zhang ◽  
Mingxing Yang ◽  
Baohua Huang ◽  
...  
Keyword(s):  
Oxygen Reduction Reaction ◽  
Specific Surface ◽  
Oxygen Reduction ◽  
Surface Area ◽  
Specific Surface Area ◽  
Active Sites ◽  
Reduction Reaction ◽  
Titania Nanotubes ◽  
Electron Conductivity ◽  
Electrocatalytic Properties

The enhanced electrocatalytic properties of rGO/TiO2NTs for the ORR are a result of increased specific surface area, number of active sites and accelerated electron conductivity.

scholarly journals Carbon-Supported Mo2C for Oxygen Reduction Reaction Electrocatalysis

Nanomaterials ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1805
Author(s):  
Dušan Mladenović ◽  
Milica Vujković ◽  
Slavko Mentus ◽  
Diogo M. F. Santos ◽  
Raquel P. Rocha ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Double Layer ◽  
Molybdenum Carbide ◽  
Reduction Reaction ◽  
Alkaline Media ◽  
Carbon Xerogel ◽  
Electrocatalytic Properties ◽  
Molybdenum Carbides

Molybdenum carbide (Mo2C)-based electrocatalysts were prepared using two different carbon supports, commercial carbon nanotubes (CNTs) and synthesised carbon xerogel (CXG), to be studied from the point of view of both capacitive and electrocatalytic properties. Cation type (K+ or Na+) in the alkaline electrolyte solution did not affect the rate of formation of the electrical double layer at a low scan rate of 10 mV s−1. Conversely, the different mobility of these cations through the electrolyte was found to be crucial for the rate of double-layer formation at higher scan rates. Molybdenum carbide supported on carbon xerogel (Mo2C/CXG) showed ca. 3 times higher double-layer capacity amounting to 75 mF cm−2 compared to molybdenum carbide supported on carbon nanotubes (Mo2C/CNT) with a value of 23 mF cm−2 due to having more than double the surface area size. The electrocatalytic properties of carbon-supported molybdenum carbides for the oxygen reduction reaction in alkaline media were evaluated using linear scan voltammetry with a rotating disk electrode. The studied materials demonstrated good electrocatalytic performance with Mo2C/CXG delivering higher current densities at more positive onset and half-wave potential. The number of electrons exchanged during oxygen reduction reaction (ORR) was calculated to be 3, suggesting a combination of four- and two-electron mechanism.

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