Evaluation of La0.6Sr0.4Co0.2Fe0.8O3-δ as a potential cathode for proton-conducting solid oxide fuel cell

The application of La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) as a potential cathode working on a BaCe0.54Zr0.36Y0.1O2.95 (BCZY) electrolyte for proton conducting solid oxide fuel cell was investigated. LSCF nanoceramic powders were synthesized by an activated carbon-assisted sol-gel process using metal nitrate-based chemicals. The LSCF powder was transformed to a slurry and spin-coated onto both surfaces of BCZY pellet to form a symmetrical cell with the configuration of LSCF|BCZY|LSCF. The symmetrical cell was subsequently sintered at 950°C for 2 h to allow a good contact formation between electrode/ electrolyte layers. The phase structural verification of the calcined powders was investigated by X-Ray diffractometer (XRD). Field-emission scanning electron microscopy (FESEM) was employed to examine the morphology of the sintered cell. The electrochemical behaviour of the symmetrical cell was studied by an electrochemical impedance spectroscopy. The formation of a single perovskite LSCF phase with a crystallite size of 20 nm was obtained at 700°C as corroborated by XRD analysis. The FESEM images showed a good contact between LSCF cathode and BCZY electrolyte at electrode/ electrolyte interfacial layer. The ASR obtained for LSCF symmetrical cell measured at 700°C with and without Pt current collector is 0.87 and 31.25 Ωcm2, respectively

Pembinaan penderia pH gentian optik pintar berasaskan reagen terpegun dan rangkaian neural tiruan (ANN) / Faiz Bukhari Mohd Suah … [et al.]

Penderia pH gentian optik berasaskan reagen terpegun dan pengoptimuman rangsangannya menggunakan rangkaian neural tiruan (artificial neural network, ANN) telah dibangunkan dalam kajian ini. Penunjuk pH iaitu bromotimol biru (BTB) telah dipilih sebagai reagen. Reagen ini telah dipegunkan di atas kopolimer Amberlite XAD 7 dengan kaedahjerapan. Teknik spektroskopi pantulan digunakan untuk pencirian reagen yang terpegun di atas Amberlite XAD 7. Penggunaan ANN dalam pengoptimuman rangsangan penderia pH gentian optik berasaskan reagen yang dipegunkan di atas Amberlite XAD 7 ini telah berjaya melebarkanjulat rangsangan linear penderia darijulat yang terhad (pH 6.00-8.00 bagi BTB) kepada julat yang lebih baik iaitu pH 2.00-11.50. Pengoptimuman rangsangan penunjuk pH ini tidak dapat dilakukan untuk keseluruhan julatpH 1.00-14.00 kerana masalah pelunturan kimia terhadap reagen yang dipegunkan. Ralat purata bagi penentuan pH bagi larutan yang tidak diketahui adalah 0.03 unit pH untuk BTB terpegun pada Amberlite XAD 7

Structural and electrochemical characterisations of lanthanum-based cobalt ferrite and barium cerate-zirconate oxides as composite cathode for proton ceramic fuel cell

This study investigated the composite cathode of LaSrCoFeO3-BaCeZrYO3 (LSCF-BCZY) in a ratio of 7: 3. A 13-mm symmetrical half-cell was fabricated using the dry pressing and spin-coating techniques to yield the configuration of LSCF-BCZY|BCZY|LSCF-BCZY. The phase of the sample was verified using the X-Ray Diffraction (XRD) spectroscopy. The electrochemical and microstructure of the half-cell were characterized using the Electrochemical Impedance Spectroscopy and Scanning Electron Microscopy (SEM), respectively. The XRD analysis showed that the single-phase structure of LSCF and BCZY was still preserved at the calcination temperature of 900oC. The half-cell demonstrated a thermally activated trend in a humidified atmosphere with area-specific resistance values of 0.25, 0.33, 1.02, 1.64, and 5.75 O.cm2 at temperatures of 800, 750, 700, 650, and 600oC, respectively. The SEM image revealed that the 10-µm LSCF-BCZY layer was well-adhered on the dense BCZY electrolyte surface. This synthesised LSCF-BCZY in the ratio of 7: 3 demonstrated excellent characteristics as a composite cathode for PCFCs

Optimization of Chiral Separation in Cypermethrin using Response Surface Methodology

Cypermethrin (CPM) is a chiral insecticide compound, consists of eight stereoisomers with similar mass, structure and functional group. Hence, due to great structural similarities which lead to difficulties to resolve and lack of isomer standards, analysis of CPM stereoisomers is still poorly developed. In this study, a Cyclosil-B type chiral column was used to separate the CPM stereoiosmers via gas chromatography-electron capture detector (GC-ECD). A multivariate technique called response surface methodology (RSM) was utilized to optimize the separation conditions for CPM stereoiosmers. Four optimization steps were designed which involved two operating parameters i.e column temperature and holding time in order to establish the temperature programming approach. The results indicate that using the designed optimal conditions (step 1, 101 oC initial temperature with 3.0 min holding time; step 2, the temperature was increased to 106 oC with 2.50 min holding time; Step 3 was 115 oC for the next temperature with 0.5 min holding time; and final temperature of 123 oC with 2.0 holding time for step 4), all the eight peaks of CPM stereoiosmers were successfully separated with high resolution and short analysis time