Abstract: A series of mesoporous carbon sample had been synthesized by using a modification of template silica, SBA-15. Sucrose was added into a large pore size of SBA-15 by using incipient wetness impregnation method. A proper carbonization and removal silica process had been done to produce large pore size of mesoporous carbon. Two electrode cells were prepared by coating mesoporous carbon into stainless steel mesh as a supercapacitor electrode. A few of electrolyte concentration also had been investigated by cyclic voltammetry using a various concentration of KOH in the range 1-12 M. It shows that 6M KOH gives a better performance of EDLC.
Abstract: In this work, microporous chitosan-succinonitrile membranes were prepared by phase separation method. The membranes were characterized using electrochemical impedance spectroscopy and scanning electron microscope. It was found that the addition of succinonitrile increased the pore size, which in turn increased the ionic conductivity of the chitosan-succinonitrile membrane.
Abstract: Titanate nanowires were synthesised by hydrothermal process in 10M NaOH aqueous solution at 200oC for 24h. The samples were washed repeatedly in HCl aq. solution and deionized water until pH ~7. Subsequently, the samples were heat-treated at 400-850°C in air for 2h. The X-ray diffraction (XRD) analysis of the sample heat-treated at 800°C showed the crystalline structure of sodium titanate (Na2Ti6O13 ), while the presence of anatase phase was detected from the sample heat-treated at 850°C. Wire-like morphology of the synthesized sample was observed using FE-SEM. The photocatalytic activity of the samples heat-treated at 600,800, 850°C and 900°C was investigated by measuring the degradation of methylene blue (MB) in aqueous solution under UV-light irradiation and more than 90% of the dye was efficiently degraded by the sample heat-treated at 850°C within 45 minutes irradiation time as compared to other tested samples.
Abstract: The microstructure, specific surface area, and pore size distribution of nickel oxide–samarium doped ceria carbonate (NiO–SDCC) composite anodes were investigated with respect to wt.% NiO. Four types of composite anode powders were prepared by mechanically mixing NiO with SDCC electrolytes at different wt.% (50:50, 60:40, 70:30 and 80:20). XRD results demonstrated that the crystalline phase structure of NiO and SDCC does not show any phase change, but only exhibits the NiO and SDCC interface within the NiO–SDCC composite anode powder. SEM and BET results show that wt.% NiO considerably influenced the particle connectivity between NiO and SDCC, particle size, specific surface area, and pore size distribution. Specific surface area, and pore size increased whereas particle size decreased with an increase in wt.% NiO. The highest surface area (11.9 m2/g) and the largest pore volume (0.14 cm3/g) were obtained for NiO–SDCC (60:40) composite anode powder. Therefore, the composite anode with large specific surface area displays the highest catalytic activity and the lowest interfacial polarization resistance at the anode/electrolyte interface.
Abstract: Titanium dioxide (TiO2) is a well-known promising photocatalyst that has been used as the photoanode in dye sensitized solar cells (DSSC). Since graphene has good electrical, mechanical and chemical properties, its use is supposed to enhance the photocatalytic activity of TiO2, the absorption of dye and enhance the mechanical strength of the layers of DSSC. There are several methods of preparing TiO2/graphene composite using complicated process and high-tech instruments. In this study, TiO2/graphene nanocomposite was prepared using two facile methods, which is achieved by mixing graphene oxide (GO) sheets with commercially available TiO2 paste and the other method was based on thermal reaction of mixed TiO2 and GO before incorporating it to the working electrode of DSSC. The quality of GO reduction in the process of making the composite was characterized by using FTIR spectra and Raman spectroscopy.
Abstract: Solid oxide fuel cells (SOFCs) offer the advantages of high efficiency, low pollution emission, and low processing cost. SOFC quality is strongly influenced by the preparation process. Composite La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) samarium-doped ceria carbonate (SDCC) cathode for low-temperature SOFCs was developed, and the effect of sintering soaking time on the physical properties of an LSCF–SDCC composite cathode was studied. Composite cathode powders with 50 wt.% LSCF and 50 wt.% SDCC were mixed before undergoing calcination and uniaxial pressing process. The pressed samples were sintered at 600 °C and soaked at 1, 2, and 3 hr. The porosity and density results obtained by the Archimedes method showed a decrement of porosity from 24.92% to 19.62% and an increment of density from 4.03 g cm−1 to 4.15 g cm−1 under 1 hr to 3 hr of soaking time. Scanning electron microscopy reveals that the grain size of the composite cathode surface increases with increasing soaking time. X-ray diffraction results demonstrate that the diffraction angles at 33o and 59o exhibit a decreasing SDCC peak because of the increasing grain size. However, the new peak of lithium chromium oxide (Li2CrO4) appears at an angle of 21.66° for 3 hr soaking time. The findings proved that soaking time influences the microstructure of the composite cathode.
Abstract: Biodiesel which comes from pure renewable resources provide an alternative fuel option for future. The rapid growth of the biodiesel industry will result in overproduction of less value glycerol and create a superfluity of this impure by-product. The synthesis of alkaline alumina catalyst for polyglycerol production via solvent free base-catalyzed etherification of low value glycerol is reported. The etherification of biodiesel derived glycerol to polyglycerol was studied in a heterogeneous catalysis under solvent free system, using alkalines over γ – alumina catalysts. All the catalysts were prepared by incipient-wetness impregnation of an aqueous solution of alkaline compounds on γ – alumina as a support. The effects of alkaline compound, reaction temperature, catalyst amount, and reaction time in conversion of glycerol to polyglycerol were investigated. The catalyst with potassium loaded on γ -alumina gave the highest basicity and the best catalytic activity for this reaction. The highest glycerol conversion into polyglycerol production was obtained with high yield 79.5% over prepared catalyst respectively. Industrially, the findings attained in this study might contribute towards promoting the biodiesel industry through utilization of its by-products.
Abstract: Zinc oxide (ZnO) is one of the promising candidates for solar water splitting application. Due to immerging of nanotechnology, ZnO nanostructures have been extensively studied and the properties are still under debate. Vertically aligned ZnO nanorods (NRs) offer higher surface-to-volume ration compared to other shapes and become the most seeked by researches ever since. The facile growth of vertically aligned ZnO NRs thin films out of two different zinc salt, namely , zinc acetate and zinc nitrate using the modified sol-gel route were performed with the assistant of ultrasonic rinse. Sonication of ZnO NRs thin films has significant improvement on the structural and optical properties. Several sonication periods have been employed to synthesize these ZnO NRs thin films. Deposited ZnO NRs films were characterized under FE-SEM, AFM, XRD and UV-Vis. Comparative investigation performed on acetate and nitrate precursor materials showed a preferable (0 0 2) with homogeneous surface formation single crystal growth, high quality transparent thin film of 3.23 eV in acetate precursor material at 30 seconds sonication were reported in this paper.
Abstract: Lignin has proved its potential role as biodegradable filler for reinforcement of composite materials derived from renewable resources. Slow release fertilizer (SRF) based on starch was tested with different lignin weight percentages (5, 10, 15, 20 wt%) to analyze its effect on mechanical properties of non-biodegraded (NB) samples before and biodegraded (BD) samples after the incubation in the aerobic soil microcosm. In all NB samples, elongation at break (EB), young’s modulus (YM) and tensile strength (TS) was improved with increasing lignin from 5 to 20 wt%. However, in all BD samples, percent change in EB, YM was increased towards higher values as the lignin percentage increases. It was also observed a significant difference (pair t-test, p < 0.05) between each composition before and after biodegradation. In BD samples with 5-15 wt% lignin, percent change in mechanical properties was non-significant (pair t-test, p > 0.05). It was further noticed that percent change in mechanical properties was low in BD samples with lignin compared to the BD samples without lignin. From the present work, it is concluded that lignin strengthens the lignin-starch matrix in NB samples and it also reduced the impact of mechanical properties loss in BD samples.