Papers by Author: Wan Ramli Wan Daud

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Authors: Raharjo Jarot, Andanastuti Muchtar, Wan Ramli Wan Daud, Norhamidi Muhamad, Edy Herianto Majlan
Abstract: Composite cathodes made of perovskite La0.6Sr0.4Co0.2Fe0.8O3 (LSCF) and SDC carbonates (SDC-(Li/Na)2CO3) were investigated in relation to their structure, morphology, thermal expansion coefficient and porosity. As a first step, the LSCF powder was prepared by sol-gel technique. This was followed by the preparation of the LSCF-SDC carbonates composite cathode by mixing the LSCF with SDC-(Li/Na)2CO3 electrolyte via solid state reaction in various compositions, i.e. 30, 40 and 50 wt.%, namely 70LSCF-30SDC7030, 60LSCF-40SDC7030 and 50LSCF-50SDC7030, respectively. The powder mixtures were then calcined at 680oC. The resultant powder was fine with surface area of about 3.39-7.42 m2/g and particle size of 0.56-0.66µm. The powder consists of two distinct phases, i.e. LSCF and SDC-(Li/Na)2CO3 as confirmed with x-ray diffraction. The microstructures were observed under scanning electron microscopy (SEM). Increasing the amount of the SDC-(Li/Na)2CO3 electrolyte in the composite cathode was found to bring the thermal expansion of the cathode closer to that of the electrolyte. The cathode pellets were later compacted at different pressures (27, 32 and 37 MPa) and sintered at 600oC. The optimum porosity (20.99-24.98%) was achieved for samples with SDC-(Li/Na)2CO3 content of 30-50% sintered at 600oC and cold pressed at 37 MPa.
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Authors: Dariush Jafar Khadem, Zahira Yaakob, Samaneh Shahgaldi, Wan Ramli Wan Daud, Edy Herianto Majlan
Abstract: One-dimensional nanostructures, like nanofibers, nanobelts, nanotubes, nanorods have been regarded as a new class of nanomaterials that have been attracted as the most promising building blocks for verity applications in the last few years. As one type of important structures with intensive research efforts have been devoted to the production and investigation of the metal oxides. Metal oxide nanofibers have different potential to play an essential role in a series of application such as optics, nanoelectronics, catalysts, sensors, storage, optoelectonics, and full cell. Copper oxide nanostructures is a promising semiconductor material with potential applications in photochemical, electrochemical, electrochromic especially in water splitting, catalysts, and fabrication of photovoltaic devices. In this paper electrospinning method via sol-gel was used to fabricate copper oxide nanofibers. Copper oxide nanofibers with different morphology were synthesized by different calcinations temperature. In this paper, effective parameters such as voltage, concentration of precursor and different calcinations temperature were characterized by thermal gravimetric analysis, scanning electron microscopy (SEM), Transmission electron microscopy, x-ray diffraction(XRD), Fourier transform infrared spectroscopy (FTIR) and Brunauer Emmett and Teller (BET).
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Authors: Samaneh Shahgaldi, Zahira Yaakob, Mostafa Ghasemi, Wan Ramli Wan Daud, Dariush Jafar Khadem
Abstract: One dimensional (1D) nanostructure materials such as nanowires, nanofibers, and nanorods with porous structures have potential for use in various applications. Electrospinning is one of the versatile techniques with the ability of producing cost-effective, large production, highly porous nanofibers and membrane with large surface to volume ratios. Poly ether sulfone (PES) is a kind of special engineering plastic with good processing characteristics. In this paper, synthesis of PES membrane was investigated by two main methods, i.e. phase inversion and electrospiing. For electrospining, the main effective parameters such as concentration of polymer and solvent, for finding the optimized condition of electrospun PES membrane was studied. The produced membranes were characterized by SEM for morphology and BET observation of surface area, permeability, flux, and mechanical propertise for different applications.
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Authors: Dedikarni, Andanastuti Muchtar, Norhamidi Muhamad, Wan Ramli Wan Daud
Abstract: Porous Ag-Bi2O3 composite cathodes on stainless steel (SS) substrate, an excellent mixed-ionic conductor that can be used as cathode material for the intermediate temperature solid oxide fuel cell (IT-SOFC) has been developed using the slurry painting method. Characterisation of the composite cathode includes the thermal analysis, morphology, and porosity of the porous cathode. Thermal analysis of the dried slurry was conducted in order to determine the heating schedule for eliminating the organic components using thermogravimetry analysis (TGA) and differential scanning calorimetry (DSC). The TGA and DSC analyses confirmed the organic vehicle was fully decomposed below 418oC and the formation of composite cathode oxide phase took place beyond 600oC. The microstructure of the thermally treated cathode was analysed using SEM and XRD. The SEM results showed that the grain size of the cathode increased with the increase of temperature during thermal treatment and the X-ray diffraction (XRD) analyses confirmed the presence of δ-Bi2O3 phase on the cathode. Porosity was obtained using the Archimedes method. The Ag2O3-Bi2O3 cathode on stainless steel substrates was found to have a porosity of 53%, 51%, 39% and 28% upon 1, 2, 3, and 4 coatings, respectively, as well as thermal treatment at 800°C for 1 hour.
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Authors: Raharjo Jarot, Andanastuti Muchtar, Wan Ramli Wan Daud, Norhamidi Muhamad, Edy Herianto Majlan
Abstract: Composite anodes made of NiO and SDC-(Li/Na)2CO3 were investigated in relation to their structure, morphology, and porosity. As a first step, the anode powder was prepared by mixing the NiO with SDC-(Li/Na)2CO3 via solid state reaction in weight percentage of 60 : 40 wt% and in various compositions of carbonates (20 and 30wt%), namely NiO-SDC8020 and NiO-SDC7030, respectively. The powder mixtures were then calcined at 680oC. The resultant powder was fine with surface area of about 13.10-13.70 m2/g and an average particle size of 0.32-0.37µm. The powders consist of two phases i.e. the cubic NiO and face-centered cubic structure SDC-(Li/Na)2CO3 as confirmed with x-ray diffraction. The microstructures were observed under scanning electron microscopy (SEM). The anode pellets were later compacted at different pressures (27, 32 and 37 MPa) and sintered at 600oC. The optimum porosity (20.99-24.78%) was achieved for samples of NiO-SDC8020 and NiO-SDC7030 sintered at 600oC and cold pressed at 32 and 37 MPa.
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Authors: Rachid Chebbi, Wan Ramli Wan Daud, Abu Bakar Mohamad, Abdul Amir Hassan Kadhum
Abstract: Electrode performance is the most important part in proton exchange membrane fuel cell system because all electrochemical processes and chemical conversions into energy occur via electrode interface. However the main problem in widespread proton exchange membrane fuel cells (PEMFCs) applications is the cost of the catalyst and life time of electrode, due to different parameters effects. Intense research imply in reducing the cost with increase the activity of catalyst in additional to other parameters (components) to make electrode for PEM more efficient with reasonable cost. This paper review recent research for the most parameters affecting performance of (Pt/C and Pt/C/M ) electrode for proton exchange membrane fuel cells (PEMFCs) such as Catalyst oxidation (degradation), and life time of the electrode using Pt/C, gas diffusion layer (GDL) thickness, and loading of PTFE in the diffusion layer, Nafion@ solution in the catalyst layer, methods of fabrication of electrode as spraying, casting, and electro deposition methods. Then the link between these parameters to achieve high performance and avoid the electrode degradation by optimized these parameters.
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Authors: Dariush Jafar Khadem, Zahira Yaakob, Samaneh Shahgaldi, Mostafa Ghasemi, Wan Ramli Wan Daud
Abstract: An important recent discovery in the membrane science is the polymeric nanofiber membrane. Membranes have many applications in protein purification, wastewater treatment and fuel cells. One of the versatile technique with the ability of producing cost-effective, highly porous non-woven membranes with large surface area is electrospining. In this study the effect of TiO2 nanoparticles in membrane performance has been investigated. A PES/TiO2 nanofibers membrane has higher flux and permeability than a pristine PES membrane. Also the measurments show that the surface area of the membrane will increase by addition of TiO2 nanoparticles. Moreover, the contact angle was investigated.
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