Structural properties of graphene oxide coatings from different sheets sizes

The structural properties of different sizes of graphene oxide (GO) sheets were observed. It is worth to mention that smaller size GO sheets (ultrasonicated 10h) exhibits higher absorption intensity, and the absorption peak was shifted towards lower wavelength (~223 nm) due to the fragmentation of the GO sheets. It has caused an extension of a π-conjugated system, thereby enhance the absorption intensity and energy. After electrophoretic deposition (EPD), the coatings exhibit a reduction in the oxygen content with oxygen-related band (ORB) values of the larger GO sheets is higher than that of small size GO sheets. The surface morphology of both the coatings are homogenous and the layers adhered well to the underlying copper. However, larger GO sheets exhibit rougher and coarser morphology than that of small size GO sheets. It is reflected in the thickness measurement where the large size GO sheets exhibit thicker film (3.16 ± 0.01 µm) while small size GO sheets possess thinner film (1.95 ± 0.02 µm)

Corrosion Protection Coatings from Size-Specified Graphene Oxide

Corrosion performance of graphene oxide (GO) coatings from different sheets sizes in 3.5 wt% NaCl solution was investigated. The GO dispersion was subjected to 5 and 10 hours of ultrasonication before electrophoretically deposited (EPD) onto the copper substrate. It was found that the EPD-GO coating from smaller sheets (10h ultrasonication) possess hydrophobic, thinner film and smooth surfaces. It is suggested that the corrosion performance of the coating from smaller GO sheets is improved due to the surface texture and compactness of the coating as compared to the larger GO sheets

Effects of deposition time and counter-electrode size on the fabrication of lscf-sdc carbonate composite cathode for sofc

The electrophoretic deposition (EPD) process has shown great potential in the development of cathodes for solid oxide fuel cell (SOFC). This study thus aimed to determine the feasibility of the electrophoretic deposition technique in producing composite cathode films. Two parameters were investigated, namely, the effects of counter electrode size and those of deposition time on the thickness and quality of an LSCF-SDC carbonate cathode composite deposited onto an SDC carbonate substrate. The effects of the changed parameters were observed by applying constant suspension pH and voltage. Five different deposition times ranging from 10 to 30 min were selected. The counter electrode sizes used were 25 × 25 mm2 and 50 × 50 mm2 . Then, the cathode composite films were sintered at 600°C for 90 min. Microstructural characterization and film thickness measurement were performed using a scanning electron microscope (SEM). The 50 × 50 mm2 counter electrode was found to produce a cathode composite film with higher thickness. The effects of the selected parameters (deposition time and counter electrode size) were also determined by analyzing the weight and thickness of the obtained LSCF-SDC carbonate films. The results showed that for the selected time interval, a film thickness of 4.6 to 30.8 μm is generated. Further studies on fabricating LSCF-SDC carbonate cathode composites by electrophoretic deposition present promising potential given that the film thickness obtained agree well with those derived in previous studies on various types of cathode materials

Structural, optical and morphological properties of pure and silver doped zinc oxide thin films

Pure Zinc oxide (ZnO) and silver doped ZnO (Ag/ZnO) thin films have potential applications in many optoelectronic devices. In this work, ZnO and Ag/ZnO thin films were prepared by a low-cost sol–gel method followed by a spin coating technique on glass substrates. Both ZnO and Ag/ZnO were spin-coated at various deposition layers (ranging from 3 to 11 deposition layers) to investigate the correlation of films’ thickness on the structural and optical properties. All the prepared films were subjected to an annealing temperature of 300 °C for 1 hr. The results showed that ZnO and Ag/ZnO XRD patterns had polycrystalline wurtzite structures with (101) direction domination. On the other hand, with the addition of silver dopant, the optical properties were improved at a transmittance value greater than 90% compared to ZnO (80% transmittance). FESEM results revealed that the ZnO thin film’s average grain measurement was about 65.4 nm, while Ag/ZnO exhibits grain measurement of approximately 69.3 nm. The surface morphologies showed that Ag/ZnO thin films exhibit a rougher surface due to the aggregation of silver nanoparticles. Despite the existence of agglomerated nanoparticles and higher deposition layer, the optical transmission of the Ag/ZnO is undistorted

Hydrophobic silica thin films by sol-gel processing and spin coating technique at low temperature

Hydrophobic silica thin films were prepared by sol-gel processing and self-assembly by chemical vapor reaction with Trimethylchlorosilane (TMCS) at low temperature. The sols were divided into Sol A with ethanol, Polyethylene glycol (PEG) and water (H2O) while Sol B were contain precursor of silica Tetraethylorthosilicate (TEOS) hydrolyze with ethanol which was stirred for 15 minutes. HCl was added into the mixture and stirred for another 10 minutes. After deposition on 1 x 1 cm corning glass using spin coating technique (two-step timer), the films were heated at 60˚C for 10 minutes and finally annealed at 150°C for 1 hour. The films were characterized by using Rudolph/Auto EL Ellipsometer, Shimadzu Spectrophotometer, Perkin Elmer Fourier Transform Infrared (FTIR) and Atomic Force Microscope (AFM). The results showed that the films thickness and refractive index were in the range of 105.2 to 112.4 nm and 1.35 to 1.38, respectively. The films were transmitted 70-80% of light (in visible range) with various bondings of C-H, Si-O-Si, Si-C and Si-OH. Surface roughness of the films was increased from 30.6 nm (silica thin film) to 140.5 nm (hydrophobic silica thin films) after modification have been done on the films by using TMCS (heated at 40˚C). It was found that the water contact angles increased when time of reaction increased from 109° to 124

Polymer blend nanocomposites for polymer electrolyte membrane fuel cell (PEMFC) applications

This chapter introduces polymer blend nanocomposites for polymer electrolyte membrane fuel cell (PEMFC) applications, beginning with a brief introduction to the fuel cell (FC) principle. Overviews of the working principles, the equations of the governing reactions, fundamental electrochemistry, and the leading applications are presented. Moreover, the proton exchange membrane fuel cell or PEMFC, membrane electrode assembly, membrane polymer blend for FC, and organic-inorganic composite membranes are detailed. A comprehensive description is provided of the types of polymer used in polymer blends, and the recent advances in additive-enhanced polymer electrolytes are also discussed

Ethanolic Mangifera Indica Leaves Extract as Green Corrosion Inhibitor

Mangifera indica (MI) or mango leaf as a green corrosion inhibitor for copper has been studied. The MI was extracted in ethanol solvent and prepared at different concentrations of 0, 0.4, 0.6 and 0.8 mg/ml in 1 M HCl solutions to imitate the corrosive environment. The as-prepared MI extract analyzed by UV-Vis Spectrophotometer shows a shoulder peak at about 370 nm, resulting from the π → π* and n → π* electronic transition of aromatic C=C and carbonyl (C=O) functional groups. A Fourier transform infrared spectroscopy (FTIR) found that the MI extract exhibits aromatic C=C, C=O groups of phenolic compounds, C-OH, and C-O stretching vibrations. The electrochemical impedance spectroscopy (EIS) and Tafel plot analysis evaluate that the optimum corrosion inhibition of copper was achieved at 0.6 mg/ml concentration. The result is supported by a positive shift in the corrosion potential, Ecorr, lower corrosion current, Icorr and corrosion rate (CR) at -0.233 V, 4.39 µA/cm2 and 0.05 mm/yr, respectively. The surface morphology of the copper substrate after the corrosion test evaluated using metallurgical microscopy shows tremendous corrosion inhibition due to the adsorption of the molecules from the MI extracts

Ethanolic mangifera indica leaves extract as green corrosion inhibitor

Mangifera indica (MI) or mango leaf as a green corrosion inhibitor for copper has been studied. The MI was extracted in ethanol solvent and prepared at different concentrations of 0, 0.4, 0.6 and 0.8 mg/ml in 1 M HCl solutions to imitate the corrosive environment. The as-prepared MI extract analyzed by UV-Vis Spectrophotometer shows a shoulder peak at about 370 nm, resulting from the π → π* and n → π* electronic transition of aromatic C=C and carbonyl (C=O) functional groups. A Fourier transform infrared spectroscopy (FTIR) found that the MI extract exhibits aromatic C=C, C=O groups of phenolic compounds, C-OH, and C-O stretching vibrations. The electrochemical impedance spectroscopy (EIS) and Tafel plot analysis evaluate that the optimum corrosion inhibition of copper was achieved at 0.6 mg/ml concentration. The result is supported by a positive shift in the corrosion potential, Ecorr, lower corrosion current, Icorr and corrosion rate (CR) at-0.233 V, 4.39 µA/cm2 and 0.05 mm/yr, respectively. The surface morphology of the copper substrate after the corrosion test evaluated using metallurgical microscopy shows tremendous corrosion inhibition due to the adsorption of the molecules from the MI extracts

From brothel to zakah

Ali was in dilemma. How would he help his childhood friend, Mastura emancipated from brothel. Was there any way in Islam to free a person in captivity? Ali remembered her story. It was five years ago when Mastura was just 17 years old, she got married to Hasnan, a stranger that she just met for two months. Mastura leaved Alor Setar for Kuala Lumpur to be with her husband. Unfortunately, her husband who was supposed to be her protector in joys and sorrows, sold her to brothel in Lorong Haji Taib. In hesitant, she was forced to become prostitute without any pay. The brothel had very strict security and only provided her with room, foods and clothes. Two years later, she got pregnant and gave birth to a baby girl named Sarah. According to Mastura, she broke out from the brothel with the help of her regular client. Escaped from brothel, Mastura hoped that she could start her life all over again in her hometown, Alor Star. That was when Ali met Mastura, where she begged for help from him.Ali had been working as the manager of Asnaf Development and Zakat Distribution Division in Lembaga Zakat Negeri Kedah (LZNK) for 10 years. He thought of how would zakah be of help to Mastura. Ali brought the matter to his boss, Haji Zakaria Othman, who had asked him to study other states practice

Structural evaluation of graphene oxide/Zinc oxide nanocomposite for corrosion mitigation

Owing to the impermeability, high hardness, and hydrophobicity of graphene oxide, there is a growing demand for the development of graphene oxide-based nanocomposite. In this research, GO/ZnO nanocomposite is prepared through a sol–gel route and further spin-coated onto copper to study its potential in corrosion mitigation. This research aims to investigate the structural properties of the nanocomposite formed by various GO sheet sizes and correlate them to the corrosion mitigation mechanism. The different GO sheet sizes were obtained by ultrasonication at 1 h, 3 h and 5 h and the samples were termed as 1 h-GO/ZnO, 3 h-GO/ZnO and 5 h-GO/ZnO, respectively. The X-ray diffraction (XRD) analysis of all samples showed the diffraction peaks at 31.8°, 34.5°, and 36.3° due to the nucleation of ZnO into the graphene structure. The crystallite size of the nanocomposite has decreased with decreasing GO sheet sizes. The Fourier transform infrared (FTIR) spectrometer revealed a strong new peak at 443 cm−1 due to Zn-O characteristic vibrations as compared to as-synthesized GO. The Brunauer-Emmett-Teller (BET) analysis showed that the GO/ZnO nanocomposites exhibited a larger surface area when the GO sheet sizes decreased. The spin-coated sample of 5 h-GO/ZnO showed a higher potential for corrosion protection at 0.017 mm/yr corrosion rate