bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Electrochemical Behaviour of Some Composite Coatings Obtained By Electrodeposition on Metallic Substrate
Authors: Branzoi Florina , Branzoi Viorel , Pacuretu Catalina , Pahom Zoia 
Published: February 2020

Nanocomposite films based on 3,4 ethylen-dioxythiophene and 3-methylthiophene with functionalized single-walled carbon nanotubes (SWANTs- polyaminobenzene sulfonic acid - CNT-PABS, SWANTs- with carboxylic acids functionalized - CNT-COOH) and different large anionic surfactants as dopants (1-dodecane sulfonic acid sodium salt, sodium dioctyl sulfosuccinate - AOT and sodium dodecylbenzenesulfonate - SDBS) were studied. It was fabricated by a simple oxidative electropolimerization method.
All the obtained composites showed improved mechanical integrity, higher electronic and ionic conductivity and exhibited larger electrode specific capacitance than the polymer alone. These nanoporous composite films were grown electrochemically from aqueous solutions such that constituents were deposited simultaneously onto substrate electrode.
The synthetic, morphological and electrical properties of the obtained nanocomposite films were compared. Scanning electron microscopy (SEM) revealed that the composite films consisted of nanoporous networks of SWCNTS (single-walled carbon nanotubes) coated with polymeric film. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) demonstrated that these composite films had similar electrochemical response rates to pure polymeric films but a lower resistance and much improved mechanical integrity. The large anionic surfactants served as dopant during the electropolymerization to synthesize polymer/CNTSF composite films. The electrochemical and physical properties of the resulting composites were evaluated by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and FT-IR spectroscopy techniques.The improved properties of the electrodes were obtained by using these composite films. The specific electrochemical capacitance of the composite films is a significantly greater value than that for pure polymer films prepared similarly. All of the composite films were a very promising electrode material for application in supercapacitor.
Photochemical Degradation of an Anionic Surfactant By TiO2 nanoparticle Doped with C, N in Aqueous Solution
Authors: Giahi Masoud , Zamiri Marzieh 
Published: February 2020

In this work, We synthesized a novel C, N-doped TiO2 nanoparticles by sol-gel method. The catalyst was characterized by X-ray powder diffractometer (XRD), transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDX). The results showed that crystallite size of synthesized C, N-doped TiO2 particles were in nanoscale. UV light photocatalytic studies were carried out using sodium naphthalene sulfonate formaldehyde (SNF) as pollutant. The effects of initial concentration of surfactant, catalyst amount, pH, addition of oxidant on the reaction rate were ascertained and optimum conditions for maximum degradation was determined. The results indicated that for a solution of 20 mg/L of sodium naphthalene sulfonate formaldehyde, almost 98.7% were removed, in pH around 4.0, 0.44 g/L photocatalyst, 1 mM K2S2O8 irradiated for 90 min. The kinetics process was studied and the photodegradation rate of SNF was found to obey pseudo-first-order kinetics equation represented by the Langmuir–Hinshelwood model.
Synthesis and Investigation of Poly(N-Isopropylacrylamide-co-N-vinylcarbazole) Hydrogels Morphological, Fluorescence and Electrical Properties
Authors: Gokceoren Argun T , Alveroglu Esra 
Published: February 2020

In this study, poly(N-Isopropylacrylamide-co-N-vinylcarbazole) gels were prepared and characterized with Fourier Transform Infrared Spectroscopy, Photoluminescence Spectroscopy, Scanning Electron Microscopy, Differential Scanning Calorimetry and DC conductivity methods. The synthesis and characterization results showed that the presence of NVCz moieties affected the thermal characteristics, topological properties and conductivity of the gels. The obtained NIPA hydrogel was found to swell in aqueous media for up to 80%, while the 50 wt/v% NVCz incorporated sample (S5) swells up to 40%. Here we report that the fluorescence emission and electrical conductivity results attest the opportunity to manufacture a tunable biomedical materials. Since, the maximum peak at 350 nm red shifted to 385nm, whilst a second peak appeared at 425 nm by the presence of the conductive PNVCz moieties allowing the possibility to control the fluorescence character of the gel. For instance an in-vivo drug release system tracking in a Fluorescence Image-Guided Surgery (FIGS) in which resolution deepness is essential in the visible wavelength could be extended when excited by means of a fluorophore compound.
Co Doped Pt3 Co Intermetallic Compound As an Efficient Catalyst for Oxygen Reduction Reaction
Authors: Zhao Yige , Liu Jingjun , Wang Feng , Li Zhilin , Ji Jing , Dou Meiling 
Published: February 2020

Abstract: The oxygen reduction reaction (ORR) is a significant cathodic reaction for renewable source applications such as fuel cells and metal-air batteries. However, the slow kinetics of ORR has become the major impediment for the commercial applications. Therefore, catalysts for the ORR are needed to lower the electrochemical over-potential. Although platinum supported on carbon (Pt/C) catalyst is now developed as the commercial catalyst, its low durability and high cost still limit the application. Thus, developing high performance catalysts with superior activity and durability is still an essential task to replace the traditional Pt/C catalyst.
Alloying Pt with a non-precious metal not only decreases the cost but also improves the catalytic performance as a result of synergistic effect between the two elements. Pt-Co system has been paid broad attention because of its relatively high activity and stability.[1] Although the state of the art Pt-Co randomly mixed alloy may exhibit high activity resulted from the so-called ligand effect,[2] its stability remains a troublesome problem owing to the severe agglomeration and dissolution during the ORR process.[3] Recently, Pt-based intermetallic compound has attracted wide interest due to its constant composition and ordered structure, and it has been demonstrated to be a desirable catalyst with excellent stability and anti-poison when compared with the randomly mixed alloy. Nevertheless, a great challenge for the practical application still exists on account of the low activity of pure intermetallic. Thus, synthesizing Pt-based catalysts with concurrently high activity and durability is still a tough problem.
This abstract mainly focuses on a new class of Co doped Pt3Co intermetallic compound as an efficient catalyst by doping a small number of Co atoms into ordered intermetallic Pt3Co phase. The obtained catalyst has the special structure with Pt3Co intermetallic as solvent and Co as solute. The electrochemical tests indicate that the gained catalyst exhibits both higher activity and durability than the commercial Pt/C catalysts, which can be attributed to the unique electronic structure of Co-doped Pt3Co intermetallic compound. This research may provide a promisingly new idea to synthesize next-generation catalysts for ORR.

References

[1] D. Wang, H. L. Xin, R. Hovden, H. Wang, Y. Yu, D. A. Muller, F. J. DiSalvo and H. D. Abruña, Nat. Mater., 2013, 12, 81-87.
[2] M. Bele, P. Jovanovič, A. Pavlišič, B. Jozinović, M. Zorko, A. Rečnik, E. Chernyshova, S. Hočevar, N. Hodnik and M. Gaberšček, Chem. Commun., 2014, 50, 13124-13126.
[3] L. Su, S. Shrestha, Z. Zhang, W. Mustain and Y. Lei, J. Mater. Chem. A, 2013, 1, 12293-12301.

Figure 1
DFT Studies of the Oxygen Reduction Reaction on Pristine and N-Doped Fe3C/Graphene Catalyst
Authors: Reda Mateusz , Hansen Heine A. , Vegge Tejs 
Published: February 2020

Proton exchange membrane fuel cells (PEMFCs) are considered to be a promising power generation systems for future mobile and stationary applications. One of the main factors that restrain their wide use is the sluggish kinetics of the oxygen reduction reaction (ORR) at the electrode. Platinum-based materials have been so far the most active catalysts for the ORR, but their high cost makes the technology rather exclusive.
In recent years, a number of non-precious ORR catalysts have been reported [1-3]. Among them, a catalyst composed of Fe3C nanoparticles encased in graphitic layers [3] draws an increasing interest due to its high stability and activity, which may be a result of the presence of a new type of active site [4]. To explain this phenomenon, we study possible catalytic sites of Fe3C/graphene interface and its N-doped variant by means of the Density Functional Theory. Additionally we study other potentially interesting systems like Fe3C with multiple graphitic layers and its N-doped variants, as well as FeN4 moieties embedded in the graphitic layers. Free energy diagrams of the 4- and 2-electron associative pathways are calculated. The aqueous environment is modeled by including several explicit water molecules. Catalytic activity and selectivity towards H2O is considered and compared with current state-of-the-art ORR catalysts.
[1] E. Proietti, F. Jaouen, M. Lefèvre, N. Larouche, J. Tian, J. Herranz, J.-P. Dodelet, Nat. Commun., 2011, 2, 416.
[2] G. Wu, K. L. More, C. M. Johnston, P. Zelenay, Science, 2011, 332, 443.
[3] Y. Hu, J. O. Jensen, W. Zhang, L. N. Cleemann, W. Xing, N. J. Bjerrum, Q. Li, Angew. Chem. Int. Ed., 2014, 53, 3675.
[4] J.-P. Dodelet, R. Chenitz, L. Yang, M. Lefèvre, ChemCatChem, 2014, 6, 1866.

Figure 1
Transition Metals (Co, Fe, Ni)-N-C Electrocatalysts for Hydrogen Evolution Reaction in Acidic and Alkaline Solutions
Authors: Zhang Lulu , Liu Wen , Shao Minhua 
Published: February 2020

Hydrogen is one of the cleanest and most promising energy carriers as an alternative energy source.1, 2 The production of hydrogen from water via a hydrogen evolution reaction (HER) has been widely studied. Platinum is believed to have the highest electrocatalytic activity for HER in both acidic and alkaline solutions. But it is very expensive and rare. Thus, more advanced precious metal free electrocatalysts for HER are required to lower the cost of electrolyzers. 3, 4

In this study, carbon-based non-precious metal catalysts (Me-N-C) were synthesized by impregnating aniline and different metal salts into a carbon matrix and pyrolyzing at 900℃ in N2 atmosphere.5, 6 The structure of obtained composites were characterized by X-ray photoelectron spectroscopy, Raman spectroscopy and X-ray diffraction. Their hydrogen evolution reaction (HER) activities were investigated in both 0.5 M H2SO4and 1 M KOH. For the first time, these non-precious metal electrocatalysts showed excellent activity for HER and good stability in both acidic and alkaline media. The Ni-C-N catalyst had the lowest onset potential while Co, Fe-C-N catalysts had smaller Tafel slopes than the former (Figure 1a).
Various active sites could contribute to the HER activity in Me-N-C catalysts (Figure 1b). Density functional theory (DFT) calculations were employed to understand the activity enhancement mechanisms and identify the active center. This work paved a new route in the design of cheap, robust and high efficient catalysts to replace Pt.

References

Zhou, W.; Zhou, J.; Zhou, Y.; Lu, J.; Zhou, K.; Yang, L.; Tang, Z.; Li, L.; Chen, S. Chemistry of Materials
2015, 27, (6), 2026-2032.

Fei, H.; Dong, J.; Arellano-Jiménez, M. J.; Ye, G.; Kim, N. D.; Samuel, E. L.; Peng, Z.; Zhu, Z.; Qin, F.; Bao, J. Nature communications
2015, 6.

Deng, J.; Ren, P.; Deng, D.; Yu, L.; Yang, F.; Bao, X. Energy & Environmental Science
2014, 7, (6), 1919-1923.

Zou, X.; Huang, X.; Goswami, A.; Silva, R.; Sathe, B. R.; Mikmeková, E.; Asefa, T. Angewandte Chemie
2014, 126, (17), 4461-4465.

Merzougui, B.; Hachimi, A.; Akinpelu, A.; Bukola, S.; Shao, M. Electrochimica Acta
2013, 107, 126-132.

Wu, G.; More, K. L.; Johnston, C. M.; Zelenay, P. Science
2011, 332, (6028), 443-447.

Figure 1
Electrocatalysis at Noble-Metal-Derived Pure Metallic Aerogels
Authors: Cai Bin , Liu Wei , Wen Dan , Eychmüller Alexander 
Published: February 2020

Pure metallic aerogels are potentially invaluable electrocatalyst materials due to their combination of the unique properties of both metals and aerogels.[1] For instance, their large specific surface area provides sufficient reactive sites, which is of great importance for the heterogeneous catalysis. Their high porosity and metallic backbones accelerates the mass and electron transfer during the electrocatalysis process. More important, the stability issues from carbon support corrosion are largely overcome based on their self-supportability.
This contribution focuses on our recent progress on the electrocatalytic investigations at a series of pure metallic aerogels. The electrocatalytic ethanol oxidation activities are doubled on the pure Pd aerogels as compared to Pd/C.[2] With the loading of enzyme, the Pd aerogel shows a 3-fold increased bio-electrocatalytic activity for glucose oxidation.[3] The kinetics of the oxygen reduction reaction is improved by a factor of 5 on the bimetallic PdPt aerogels, which also shows a significantly increased stability as compared to Pt/C.[4] Additionally, we employed an alloyed PdNi hollow nanosphere aerogel to further investigate the effects of morphology and alloying on electrocatalysis.[5] The mass and specific activities for alcohol oxidation are improved by a factor of 5.6 and 4.2, respectively, as compared to Pd/C.

References

[1] W. Liu, A. K. Herrmann, N. C. Bigall, P. Rodriguez, D. Wen, M. Oezaslan, T. J. Schmidt, N. Gaponik, A. Eychmüller, Acc. Chem. Res.
2015, 48, 154-162.
[2] W. Liu, A. K. Herrmann, D. Geiger, L. Borchardt, F. Simon, S. Kaskel, N. Gaponik, A. Eychmüller, Angew. Chem. Int. Ed.
2012, 51, 5743-5747.
[3] D. Wen, A. K. Herrmann, L. Borchardt, F. Simon, W. Liu, S. Kaskel, A. Eychmüller, J. Am. Chem. Soc.
2014, 136, 2727-2730.
[4] W. Liu, P. Rodriguez, L. Borchardt, A. Foelske, J. Yuan, A. K. Herrmann, D. Geiger, Z. Zheng, S. Kaskel, N. Gaponik, R. Kotz, T. J. Schmidt, A. Eychmüller, Angew. Chem. Int. Ed.
2013, 52, 9849-9852.

[5] B. Cai, D. Wen, W. Liu, A-K Herrmann, A. Benad and A. Eychmüller, Angew. Chem. Int. Ed.
2015, 54, 13101-13105.

Figure 1
Metallophthalocyanine/C/Nafion Composites for Electrocatalysis of Oxygen Reduction
Authors: Yazar Zuhal , Piskin Mehmet , Odabas Zafer , Ozkaya Ali Riza 
Published: February 2020

Oxygen reduction (OR) is a critical reaction occurring at one of the electrodes of both fuel cells and metal-air batteries. However, this reaction has slow electrode kinetics and thus, the catalysis of this reaction has vital importance. The studies in literature showed that some phthalocyanine (Pc) complexes had the ability of displaying high catalytic performance for dioxygen reduction, due to their highly conjugated π-electrons systems and rich redox properties.1 There is a strong relationship between the redox properties of Pc compounds and their efficiency as OR catalyst. Thus, the determination of the electron transfer properties of novel Pc derivatives is highly important.
This work involves the identification of redox properties of various novel mononuclear tetra-2,6-dimethoxy-substituted cobalt(II), iron(II), manganese(II) and nickel(II) Pcs by voltammetry and electrocolorimetry supported in situ spectroelectrochemistry in nonaqueous solution medium. It also includes determination of their suitability for usage as OR catalyst in energy conversion and/or storage devices such as fuel cells and metal-air batteries. In situspectroelectrochemical measurements provided critical support for the complete assignment of the redox processes, i.e., whether the reactions are metal- or ligand-based. The complexes displayed enriched reversible or quasi-reversible ligand and/or central metal-based one-electron redox processes. The electrocatalytic performances of the novel Pc complexes with different metal centers towards OR have been tested and compared by dynamic rotating disk and rotating ring-disk voltammetry measurements of the MPc/C(Vulcan XC-72)/Nafion modified glassy carbon electrodes in aqueous medium. In general, the complexes display different catalytic performances depending on the differences in the interactions of their metal centers with oxygen.

References

[1]. İ. Koç, M. Özer, A.R. Özkaya, Ö. Bekaroğlu, Dalton

Trans.,
32, 6368–6376 (2009).

Acknowledgement: This work was supported by Marmara University, Scientific Research Projects Committee (Project No: FEN-C-YLP-080715-0345).

Fig.1. Molecular structure of mononuclear tetra-beta substituted metal Pc template.

Figure 1
Pd/CNT Catalysts for Electrochemical Oxidation of Small Organic Molecules in Alkaline Media
Authors: Estrada Jose , Flores Jennifer , Nguyen Kelly , Haan John , Muneeb Omar 
Published: February 2020

The development of the alkaline anion exchange membrane (AEM) for the direct liquid fuel cell opened up opportunities for the use of new fuels (that oxidized inefficiently in PEM fuel cells) and new catalysts (that corroded easily in PEM fuel cells). In this work, we explore the effect of a CNT support for Pd catalysts for the oxidation of various alcohol and formate fuels in alkaline media.
We found that the CNT support provided a significant advantage over standard, activated carbon support in several of the fuels. The increase in oxidation rate in formate, for example, was 5-fold. However, the oxidation rate of propanol was not significantly enhanced by the CNT support.
We are presently exploring the scientific reason for the enhanced oxidation rates by the CNT support using XRD and XPS analysis. Masel, et al, suggested that in formic acid the CNT provides enhancement due to its electronic properties, and a shift in Pd 3d5/2­
binding energy supports this. However, we are presently investigating why the promotion in alkaline media is so much greater than in acidic media, even for the formate (compared with formic acid).
Effect of Water-to-Surfactant Ratio (ωo) in the Ynthesis of Pt/Mwcnts By Inverse Microemulsion for the Oxygen Reduction Reaction
Authors: Silva-Carrillo Carolina , Félix-Navarro Rosa María , Reynoso-Soto Edgar Alonso , Paraguay-Delgado Francisco , Alonso Gabriel 
Published: February 2020

Hybrid materials based on platinum nanoparticles deposited on carbon nanotubes (Pt/MWCNTs) have been widely used in recent years as catalysts for oxygen reduction reaction (ORR). RRO is reaction most important for many environmental applications like electric energy generations by fuel cell or hydrogen peroxide production for degradation of pollutants in water. The electrochemical ORR proceeds via two routes, one direct transfer four electrons to produce water; and an indirect route transfer of two electrons producing hydrogen peroxide (H2O2). The electrocatalytic activity and kinetics of Pt/MWCNT catalysts in RRO depends of particle size, the surface atomic structure and the homogeneous distribution of the platinum particles on the carbon support, these three parameters are controlled by the synthesis method used.
Reverse microemulsions it’s a colloidal dispersion of water in oil stabilized by a surfactant film. The aqueous core of the reverse micelles plays a crucial role defining the size of formed particles. The water pool in the microemulsion solubilizes the reactants and provides the stage where the reaction occurs; because of this, the particle size can be controlled varying water concentration. The relation of water core with surfactant concentration is given by ω (ω=[H2O]/[surfactant]). The amount of water within the micelle controls the amount of ions of the metal precursor and reducing agent as well as the lability of Interfas, which dictates the micellar exchange rate.
In this work is presented the effect of W in the activity of the Pt/MWCNT nanomaterial in the oxygen reduction reaction (ORR) and the reaction mechanism. Pt/MWCNT nanomaterials synthesized with a ω=22 and 91 show particles with mean diameters of 1.3 nm and 2.5 nm, respectively. Employing a ω=45 in the synthesis of nanomaterial Pt/MWCNT showed an average nanoparticle diameter of 3.2 nm, also the platinum loading was 2 times that nanomaterials synthesized with a W of 22 and 91. The nanomaterial synthesized with a ω=45 showed greater electrocatalytic activity than the other two nanomaterials, although a decrease in mass transfer was observed in this nanomaterial, besides the mechanism according to the Koutecky-Levich graphs was O2 + 2H + + 2e-→ H2O2. Pt/MWCNT anomaterials synthesized with a ω=22 and 91 showed the following mechanism : O2 + 4H+ + 4e-→2H2O. High values in the Tafel slopes of Pt/MWCNT nanomaterial synthesized with ω=45 confirm the presence of H2O2 on the surface.

Figure 1
Niobium Oxide/Carbon Supported Platinum and Platinum-Cobalt Nanocomposites As Electrocatalysts for Fuel Cells
Authors: Kepeniene Virginija , Stagniunaite Raminta , Tamasauskaite-Tamasiunaite Loreta , Norkus Eugenijus 
Published: February 2020

In the present work, carbon and niobium oxide/carbon supported the Pt and PtCo catalysts (denoted as Pt/C, PtNb2O5/C and PtCoNb2O5/C) were fabricated by means of the rapid microwave heating method. The synthesized catalysts were examined by transmission electron microscopy, X-ray diffraction and inductively coupled optical emission spectroscopy. The electrocatalytic activity of the PtNb2O5/C, PtCoNb2O5/C and Pt/C catalysts towards the oxidation of ethanol and reduction of oxygen was investigated by cyclic voltammetry and chrono-techniques.
It was found that Pt nanoparticles of ca. 1-6 nm in size were successively deposited onto the surface of carbon. Pt nanoparticles were uniform and well dispersed on the surface of carbon.
The PtNb2O5/C, PtCoNb2O5/C and Pt/C catalysts with Pt loadings of 0.114, 0.285 and 0.128 mg Pt cm–2, respectively, were synthesized.
Ethanol oxidation current densities were found to be ca. 6 and 12 times higher at the PtNb2O5/C and PtCoNb2O5/C catalysts, respectively, in comparison with those at the Pt/C catalyst.
In the case of oxygen reduction, the PtCoNb2O5/C catalyst outperforms the PtNb2O5/C and Pt/C catalysts towards oxygen reduction and shows higher onset potential, as well as higher current density towards the oxygen reduction reaction as compared with those at the aforementioned catalysts.
Kinetic Study of the Oxygen Reduction Reaction on Alpha-Ni(OH)2 and Alpha-Ni(OH)2 Supported on Graphene Oxide
Authors: Farjami Elaheh , Deiner L. Jay 
Published: February 2020

Development of active non-noble metal catalysts for the oxygen reduction reaction is critical for a range of electrochemical energy storage and conversion technologies. We have recently discovered that alpha nickel hydroxide supported on graphene oxide (α-Ni(OH)2/GO) displays surprising activity for the oxygen reduction reaction in alkaline media. In comparison to α-Ni(OH)2 alone or graphene oxide alone, α-Ni(OH)2/GO possesses a lower onset potential, lower peak current potential, and higher peak current density, suggesting a synergy between the GO support and the α-Ni(OH)2 particles. To investigate the origin of this synergy, we present a comprehensive kinetic analysis of the supported and unsupported α-Ni(OH)2 catalyst. Rotating disk electrode linear sweep voltammetry furnishes electron transfer numbers, kinetic rate constants, and reaction orders which provide preliminary evidence for similar elementary steps occurring on supported and unsupported α-Ni(OH)2, but modifications in activity arising from differences in the activation energy for adsorption of O2 and of reaction intermediates.