Electrochemical impedance and morphological characterization of platinum-modified polyaniline film electrodes and their electrocatalytic activity for methanol oxidation

2003 ◽  
Vol 544 ◽  
pp. 121-128 ◽  
Author(s):  
Lin Niu ◽  
Qiuhong Li ◽  
Fenghua Wei ◽  
Xiao Chen ◽  
Hao Wang
2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
S. S. Mahapatra ◽  
S. Shekhar ◽  
B. K. Thakur ◽  
H. Priyadarshi

Electropolymerization of aniline at the graphite electrodes was achieved by potentiodynamic method. Electrodeposition of Pd (C-PANI-Pd) and Ni (C-PANI-Ni) and codeposition of Pd-Ni (C-PANI-Pd-Ni) microparticles into the polyaniline (PANI) film coated graphite (C-PANI) were carried out under galvanostatic control. The morphology and composition of the composite electrodes were obtained using scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX) techniques. The electrochemical behavior and electrocatalytic activity of the electrode were characterized using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and chronoamperometric (CA) methods in acidic medium. The C-PANI-Pd-Ni electrode showed an improved catalytic performance towards methanol oxidation in terms of lower onset potential, higher anodic oxidation current, greater stability, lower activation energy, and lower charge transfer resistance. The enhanced electrocatalytic activity might be due to the greater permeability of C-PANI films for methanol molecules, better dispersion of Pd-Ni microparticles into the polymer matrixes, and the synergistic effects between the dispersed metal particles and their matrixes.


2011 ◽  
Vol 2011 ◽  
pp. 1-16 ◽  
Author(s):  
S. S. Mahapatra ◽  
J. Datta

The Pt-Pd/C electrocatalyst was synthesized on graphite substrate by the electrochemical codeposition technique. The physicochemical characterization of the catalyst was done by SEM, XRD, and EDX. The electrochemical characterization of the Pt-Pd/C catalyst for methanol electro-oxidation was studied over a range of NaOH and methanol concentrations using cyclic voltammetry, quasisteady-state polarization, chronoamperometry, and electrochemical impedance spectroscopy. The activity of methanol oxidation increased with pH due to better OH species coverage on the electrode surface. At methanol concentration (>1.0 M), there is no change in the oxidation peak current density because of excess methanol at the electrode surface and/or depletion of OH−at the electrode surface. The Pt-Pd/C catalyst shows good stability and the low value of Tafel slope and charge transfer resistance. The enhanced electrocatalytic activity of the electrodes is ascribed to the synergistic effect of higher electrochemical surface area, preferred OH−adsorption, and ad-atom contribution on the alloyed surface.


2021 ◽  
Vol 4 (1) ◽  
pp. 58
Author(s):  
S Mohanapriya ◽  
V Raj

Nanoporous nickel has been prepared by electrodeposition using non-ionic surfactant based liquid crystalline template under optimized processing conditions. Physicochemical properties of nanoporous nickel are systematically characterized through XRD, SEM and AFM analyses. Comparison of electrocatalytic activity of nanoporous nickel with smooth nickel was interrogated using cyclic voltammetry (CV), chronoamperometry (CA) and electrochemical impedance spectroscopy (EIS) analyses. Distinctly enhanced electrocatalytic activity with improved surface poisoning resistance related to nanoporous nickel electrode towards methanol oxidation stems from unique nanoporous morphology. This nanoporous morphology with high surface to volume ratio is highly beneficial to promote active catalytic centers to offer readily accessible Pt catalytic sites for MOR, through facilitating mass and electron transports.


Author(s):  
S Mohanapriya ◽  
V Raj

Nanoporous nickel has been prepared by electrodeposition using non-ionic surfactant based liquid crystalline template under optimized processing conditions. Physicochemical properties of nanoporous nickel are systematically characterized through XRD, SEM and AFM analyses. Comparison of electrocatalytic activity of nanoporous nickel with smooth nickel was interrogated using cyclic voltammetry (CV), chronoamperometry (CA) and electrochemical impedance spectroscopy (EIS) analyses. Distinctly enhanced electrocatalytic activity with improved surface poisoning resistance related to nanoporous nickel electrode towards methanol oxidation stems from unique nanoporous morphology. This nanoporous morphology with high surface to volume ratio is highly beneficial to promote active catalytic centers to offer readily accessible Pt catalytic sites for MOR, through facilitating mass and electron transports.


2009 ◽  
Vol 59 (12) ◽  
Author(s):  
Tanta Spataru ◽  
Maria Marcu ◽  
Alexandra Banu ◽  
Eugen Roman ◽  
Nicolae Spataru

Electrochemical deposition of polytyramine (PTy) was performed by cyclic voltammetry and it was observed that, in acidic media, 20 to 50 consecutive deposition cycles allowed us to obtain polymer coatings with good conductivity and high porosity. The polytyramine layers were used as a matrix for electrochemical deposition of platinum and the electrocatalytic activity for methanol oxidation of the composite material thus obtained was put in evidence.


Catalysts ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1128
Author(s):  
Vijay Khanal ◽  
Eric Soto-Harrison ◽  
Dhanesh Chandra ◽  
Narmina O. Balayeva ◽  
Detlef W. Bahnemann ◽  
...  

A simplified ammonolysis method for synthesizing single phase TaON nanoparticles is presented and the resulting photoelectrochemical properties are compared and contrasted with as-synthesized Ta2O5 and Ta3N5. The protocol for partial nitridation of Ta2O5 (synthesis of TaON) offers a straightforward simplification over existing methods. Moreover, the present protocol offers extreme reproducibility and enhanced chemical safety. The morphological characterization of the as-synthesized photocatalysts indicate spherical nanoparticles with sizes 30, 40, and 30 nm Ta2O5, TaON, and Ta3N5 with the absorbance onset at ~320 nm, 580 nm, and 630 nm respectively. The photoactivity of the catalysts has been examined for the degradation of a representative cationic dye methylene blue (MB) using xenon light. Subsequent nitridation of Ta2O5 yields significant increment in the conversion (ζ: Ta2O5 < TaON < Ta3N5) mainly attributable to the defect-facilitated adsorption of MB on the catalyst surface and bandgap lowering of catalysts with Ta3N5 showing > 95% ζ for a lower (0.1 g) loading and with a lamp with lower Ultraviolet (UV) content. Improved Photoelectrochemical performance is noted after a series of chronoamperometry (J/t), linear sweep voltammetry (LSV), and electrochemical impedance spectroscopy (EIS) measurements. Finally, stability experiments performed using recovered and treated photocatalyst show no loss of photoactivity, suggesting the photocatalysts can be successfully recycled.


Coatings ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 783 ◽  
Author(s):  
Muna Ibrahim ◽  
Karthik Kannan ◽  
Hemalatha Parangusan ◽  
Shady Eldeib ◽  
Omar Shehata ◽  
...  

ZnO-NiO nanocomposite with epoxy coating on mild steel has been fabricated by the sol–gel assisted method. The synthesized sample was used to study corrosion protection. The analysis was performed by electrochemical impedance spectroscopy in 3.5% NaCl solution. The structural and morphological characterization of the metal oxide nanocomposite was carried out using XRD and SEM with Energy Dispersive Absorption X-ray (EDAX) analysis. XRD reveals the ZnO-NiO (hexagonal and cubic) structure with an average ZnO-NiO crystallite size of 26 nm. SEM/EDAX analysis of the ZnO-NiO nanocomposite confirms that the chemical composition of the samples consists of: Zn (8.96 ± 0.11 wt.%), Ni (10.53 ± 0.19 wt.%) and O (80.51 ± 3.12 wt.%). Electrochemical Impedance Spectroscopy (EIS) authenticated that the corrosion resistance has improved for the nanocomposites of ZnO-NiO coated along with epoxy on steel in comparison to that of the pure epoxy-coated steel.


1987 ◽  
Vol 134 (7) ◽  
pp. 1645-1649 ◽  
Author(s):  
Hiroshi Okamoto ◽  
Go Kawamura ◽  
Akira Ishikawa ◽  
Tetsuichi Kudo

2016 ◽  
Vol 78 (3) ◽  
Author(s):  
Salmah Mohd Ghazali ◽  
Hasiah Salleh ◽  
Mohd Sabri Mohd Ghazali ◽  
Ahmad Nazri Dagang ◽  
Azmi Zakaria ◽  
...  

In this research, the effect of scan numbers of titania nanocrystals (TiO2 NCs) on the morphological and electrical characteristics of hybrid thin-films is investigated. These hybrid thin-films consist of a combination of organic (Piper Betle Linn extraction and Poly (3-hexytlthiophene) (P3HT)) and inorganic TiO2 NCs (anatase structure) materials. These hybrid thin-films are fabricated in bilayer heterojunction of ITO/TiO2 NCs/P3HT/Piper Betle Linn via electrochemistry method using Electrochemical Impedance Spectroscopy (EIS). The scan numbers of TiO2 NCs are varied by 1, 3 and 5 number of scans. The morphological characterization is carried out via Field Emission Scanning Electron Microscopy (FESEM) meanwhile the electrical characteristic of the hybrid thin-film is measured by using four point probes. FESEM image indicates the particle size was found to be around 17-34 nm. The increment of scan number of TiO2 NCs from one to five scan numbers of TiO2 NCs in bilayers thin films showed that the atomic percentage of titanium decrease from 5.23% to 2.20%. This result indicates that as the thickness of thin films increases, the electrons required more energy to excite into conduction band of TiO2. Meanwhile, the electrical conductivities of hybrid solar cell increase from 0.385 Scm-1 to 0.389 Scm-1 as the scan numbers of TiO2 increase from one to three, however the electrical conductivity decrease to 0.346 Scm-1 at five scan numbers. As a conclusion, this study shows that the morphological and electrical properties of hybrid thin-films can be significantly affected by the scan number of TiO2 NCs.


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