Papers by Keyword: Platinum

Abstract: The oil industry increasingly exploits ‘heavy oils’ which are highly viscous and difficult to extract in a ‘clean’ way. Heat and ‘cracking’ catalysts facilitate extraction e.g. by applying the ‘Toe-to-Heel Air Injection’ (THAI) and ‘Catalytic Process In-Situ’ (CAPRI) techniques. Cracking catalysts include palladium. Use of Pd-catalyst is uneconomic but by using palladium deposited on bacterial cells (in combination with other PMs) a waste can be turned into a valuable product. Road dusts contain precious metals (PMs) which arise from automotive catalytic converters. Once washed from roads the PMs are dispersed to the environment. Model r oad dust solutions were produced to simulate acid leaching of road dust to solubilise the PMs. Bacteria cannot directly recover PMs from acidic leachate but by lightly depositing Pd(0) ‘seeds’ enzymatically the resulting ‘bio-Pd’-catalyst accumulates PMs from waste model leachate. The bio-catalyst was assessed in the reduction of heavy oil viscosity compared to a commercial catalyst, achieving this reduction with significantly less coke formation, which was not attributable to the biomass component alone.

Abstract: Gamma spectrums were measured during X-ray transmission through solutions such as sodium chloride solution with increasing quintuple concentration of NaCl and cisplatin with increasing quintuple concentration of platinum. It was shown that the number of photons with an energy of 511 keV is 29.6% more in cisplatin solution with increasing quintuple concentration of platinum (5*cisplatin) than sodium chloride solution increasing quintuple concentration of NaCl. The result allows us to consider cisplatin as a possible radiomodificator for radiation therapy.

Abstract: In the present work, vanadium pentoxide (V₂O₅) nanoparticles have been investigated for monitoring ethanol (C₂H₅OH) at ppm levels in air. A one-step flame spray pyrolysis (FSP) process has been applied for the synthesis of vanadium pentoxide (V₂O₅) and platinum-loaded vanadium pentoxide (Pt-V₂O₅) nanoparticles. The samples have been studied to characterize their morphological and microstructural properties by X-ray diffraction and transmission electron microscopy. Pt addition to V₂O₅ samples were verified by energy dispersive X-ray spectrometry mode. The specific surface area of the nanoparticles was measured by nitrogen adsorption method. The application of the produced nanoparticles as sensitive and selective ethanol resistive sensor has been demonstrated. The Pt-loaded V₂O₅ sensor has shown higher response towards ethanol at ppm-level concentrations compared to unloaded one.

Abstract: Platinum is commercially used in the catalytic industry for ages. The use of platinum has been significantly practiced because of its enhancing properties. There are a few advantages of using platinum such as high selectivity, high yield, high stability and able to undergo improvisation. However, when platinum lifetime is out, it is treated mainly as waste. Low recovery of platinum spent catalyst brought to the existence of recovery method using acidic and alkaline method. Proved to be harmful, green subtances were used as substitute for the chemical in recovering platinum. Therefore, a cheaper, safer and more environmentally method of recovery. Thus,this paper review about recovering platinum using palm oil leaf and how it is better than the existed chemical based method.

Abstract: Platinum doped Tungsten Oxide (WO₃/Pt) has been successfully coated on the glass substrate using spray deposition method. Doping of Pt on WO₃ was carried out by phodeposition method. The amount of Pt was varied by weight fraction of 0%, 1%, 2%, 4%. These films were characterized using X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). It is found that the crystal structure of WO₃ was not change with the Pt addition. However, the dominant plane orientation and the size of crystal were influenced by Pt addition. The crystal size increases with increasing the amount of Pt. After Pt addition, the film morphology showed the presence of pillar structure. The photocatalytic activity test resulted that WO₃/Pt photocatalyst has the ability for degradation of methylene blue (MB) under sunlight irradion. Significantly, the maximum efficiency of photodegradation was observed at 4% Pt doping amount in the WO₃ sample.

Abstract: Catalyst-referred etching (CARE) is a planarization method based on the chemical etching reaction, which does not need abrasives. In this paper, CARE was applied to the planarization of 6-inch silicon carbide (SiC) wafers, and removal properties were investigated. The etching rate was about 20nm/h, which is almost equal to that of 2-inch SiC wafer (16 nm/h). The rms roughness was reduced along with the removal depth, and step-terrace structure was observed in whole area of the on-axis wafer surface.

Abstract: In our investigation we focused on effects of the degradation of Pt-Rh gauzes from three different industrial catalytic systems. The aim of the study was to compare the degree and the mechanism of degradation under different conditions (pressure, temperature, gas flow direction). The investigation was performed on about 80μm diameter wires after long (6 months) exposition to chemically aggressive environment. Microscope observations and microtomography analysis showed that all wires surfaces were strongly developed by etching and deposition processes occurring under extreme conditions. Each wire differed in rate of degradation and morphology of the characteristic cauliflower-shape growths. Also differences in elements distribution on both, surface and cross sections, were observed. Obtained results can be basis of further investigation on improvement of endurance of PtRh alloys in high temperature chemical application.

Abstract: The presented paper discusses a possibility of developing and modifying surface of nickel substrate by applying of Ni, Pt, Pt/Ni porous metallic layers by zol-gel method using EDTA as a complexing agent. Then gel containing Pt or Ni or Ni/Pt was decomposed during pyrolysis process and then transformed into the porous metal during oxidation/reduction process at 600°C respectively in air or H₂ atmosphere. The thermal decomposition of gels were studied by TG/DTA method. Compositions of oxidized as well as metallic layers were determined by EDX and XRD method. The morphology of Pt, Ni and Pt/Ni layers were studied by SEM method.

Abstract: This paper presents the fabrication and characterization of platinum-based catalytic microcombustor. The platinum catalyst was deposited onto type-304 stainless steel using the wet impregnation method. The stainless steel undergoes controlled conversion coating treatment in sulfuric acid solution to increase the porosity of its surface before the deposition of the platinum catalyst. The scanning electron microscopy result showed that the porosity on the stainless steel surface will depend on the length of treatment time in the sulfuric acid solution. The surface porosity increased as the treatment time increases. The stainless steel surface morphology changed from smooth to ‘cracked-mud’ morphology after treatment in sulfuric acid solution. The treatment time also provide significant effect to the amount of platinum deposited on the stainless steel surface. The energy dispersive x-ray analysis showed that the amount of deposited platinum for 10 seconds of treatment time was 0.68 wt%, whereas those for 20 and 30 seconds were 0.87 wt% and 1.10 wt%, respectively. Liquefied petroleum gas-air combustion result showed that the flame completely submerged inside the microcombustor with a catalyst, whereas portions of flame can be observed at the exhaust for the microcombustor without a catalyst. The minimum air-to-fuel ratios before the combustion blow-out for 10, 20, and 30 seconds of treatment time was 0.5, 0.4, and 0.3 respectively.

Abstract: The wet impregnation method for catalytic microcombustor was characterized by using platinum as a catalyst. The main purpose of this study is to increase the surface porosity of the catalyst support. A high surface porosity indicates that a high amount of catalyst was deposited within the surface areas. The performance of the catalytic microcombustor improves with increasing catalytic surface area. The stainless steel catalyst support was treated with sulfuric acid solution containing polyvinyl (3.89 wt%) and propargyl alcohol (1.48 wt%). Combustion test was performed using LPG-air to test the performance of the catalyst. The surface support treated with polyvinyl (PVA) showed a higher surface porosity and combustion blow-out limit compared with propargyl alcohol. The combustion mode changes from surface to submerged combustion after the catalyst was deposited in the support surface.