PREPARATION AND CHARACTERIZATION OF CDO-NIO NANOCOMPOSITES USING LASER PULSE DEPOSITION APPROACH

In this manuscript, CdO-NiO nanocomposites (in the form of thin film) with particular concentrations are paper using laser pulse deposition technique under the effect of different laser energies (300, 400, 500, and 600 mJ). Furthermore, the structural, morphological, and optical analyses are thoroughly investigated. In particular, well-oriented deposited films are observed by using X-ray diffraction technique, while the morphological properties are investigated using two different techniques namely field emission scanning electron microscopy and atomic force microscopy which have revealed small nanoparticles with approximate diameter of 50 nm and average surface roughness ranging between 6.5 and 20.3 nm for laser energies of 400 and 600 mJ, respectively. Continuously, the optical technique applied which used UV-Vis analysis has showed cut-off phenomenon at around 339 nm. In the meanwhile, the energy band gap for the deposited films was found to be within the range of 2.2 and 2.4 eV, as a result of different laser energies.

Preparation of Pt/CNT Thin-Film Electrodes by Electrochemical Potential Pulse Deposition for Methanol Oxidation

High-quality performance of catalysts is increasingly required to meet industry exigencies. However, chemical synthesis is often insufficient to maximize the potential properties of the catalysts. On the other hand, electrochemical synthesis has arisen as a promising alternative to overcome these limitations and provide precise control in the preparation of catalysts. In this sense, this work involved the well-controlled electrochemical synthesis of a catalyst based on platinum nanoparticle deposition on carbon nanotubes using only electrochemical treatments. Thin films of functionalized carbon nanotubes were cast onto the surface of a glassy carbon electrode using potential pulsed electrodeposition, resulting in a better distribution of the carbon nanotubes on the electrode when comparing with traditional methods. Then, platinum nanoparticles were electrodeposited on the carbon nanotube-modified electrode. To check the performance of the catalyst and the relevance of the electrochemical synthesis treatments, the samples were analyzed as electrocatalysts towards methanol electrooxidation, showing an important improvement in the catalytic activity in comparison with electrodes that were prepared by traditional methodologies.

A Review on Nano-/Microstructured Materials Constructed by Electrochemical Technologies for Supercapacitors

The article reviews the recent progress of electrochemical techniques on synthesizing nano-/microstructures as supercapacitor electrodes. With a history of more than a century, electrochemical techniques have evolved from metal plating since their inception to versatile synthesis tools for electrochemically active materials of diverse morphologies, compositions, and functions. The review begins with tutorials on the operating mechanisms of five commonly used electrochemical techniques, including cyclic voltammetry, potentiostatic deposition, galvanostatic deposition, pulse deposition, and electrophoretic deposition, followed by thorough surveys of the nano-/microstructured materials synthesized electrochemically. Specifically, representative synthesis mechanisms and the state-of-the-art electrochemical performances of exfoliated graphene, conducting polymers, metal oxides, metal sulfides, and their composites are surveyed. The article concludes with summaries of the unique merits, potential challenges, and associated opportunities of electrochemical synthesis techniques for electrode materials in supercapacitors.

Doping effect by SiO2 on optical properties of ZnO Thin Films Prepared by pulsed laser depositions (PLD) technique

In this paper,Zinc oxide was dopped by various concentrations (5,10,15,20,25) % wt, silicon oxide The mixture was deposited on glass substrate by laser pulse deposition at room temperature to obtain (Zn2SiO4) thin films .The optical properties of thin films prepared on spectral absorption and transmission recording were studied at the wavelength range (200- 1100) nm. Some of the optical constants, including absorptance, transmission, absorption coefficient, and energy gap are calculated before and after annealing at (400 ̊C) for (1 hr). Absorptance values and absorption coefficient increase after doping and transmission and energy gap decreases after the doping. Absorbance values and absorption coefficient decreases after annealing and transmission and energy gap increase after the annealing . http://dx.doi.org/10.25130/tjps.24.2019.015

Effect of SiO2 ratio on electrical Properties of SiO2:ZnO Thin Films Prepared by pulsed laser depositions (PLD) technique

In this paper zinc oxide was dopped by various concentrations (5,10,15,20,25) % of silicon dioxide. The mixture was deposited on glass substrate by laser pulse deposition at room temperature to obtain (Zn2SiO4) thin films. The D.C conductivity showed a decrease in activation energy by increasing doping from (Ea1=0.096 eV) to (Ea1=0.075 eV) before annealing and after annealing from (Ea1=0.048 eV) to(Ea1=0.027 eV). Hall effect showed that the concentration of carriers increases from (2.79 ×1018cm-3) to (14.29× 1018cm-3 ) before annealing and from (0.30×1016cm-3) to (26.25×1016cm-3) after annealing. The mobility decreases from(2.3cm2/v. sec) to (0.99cm2/v. sec) before annealing and from (7cm2/v. sec) to (2.5cm2/v . sec). http://dx.doi.org/10.25130/tjps.23.2018.173