Papers by Keyword: Palladium Catalyst

Abstract: Supported 3wt%Pd/α-Al₂O₃ catalyst was tested in selective oxidation of 1,2-propanediol by molecular oxygen. It was found that the catalyst is active in an alkaline water solution. Lactic acid was obtained as the main product of the reaction. Influence of different reaction conditions on 1,2-PDO conversion and oxidation process selectivity was studied. Partial kinetic orders of the reaction with respect to 1,2-propanediol, c₀(NaOH), p(O₂), n(1,2-PDO)/n(Pd)) were determined and an experimental kinetic model of the catalytic oxidation reaction was obtained. Activation energy of the process was calculated and was found to be about 53 ± 5 kJ/mol.

Abstract: We reported that titania ceramic coating loaded with palladium catalyst worked as an optical hydrogen gas sensor at room temperature. The palladium metal of this sensor worked as a catalyst not only for room-temperature operation but also for high selectivity to hydrogen gas. Precise control of metal/ceramic interface between the titania and the palladium was very important in order to improve the sensor performance such as sensitivity, response time, recovery time. Influence of a difference in palladium-catalyst loading method (photodeposition and sputtering) on the optical hydrogen gas sensing properties for the titania-based sensor was investigated. It was found that the catalytic loading process significantly affected the optical hydrogen characteristics of the titania-based coating.

Abstract: Transparent titania coating was formed onto a flexible polycarbonate plastic substrate by low-temperature fabrication process below 100 °C consisting of a sol-gel technique and a hot water treatment method. The titania coating with high transparency showed a good photocatalytic activity under ultraviolet (UV) light irradiation. Palladium metal acts as a catalyst for dissociative adsorption of hydrogen gas at room temperature under an atmospheric pressure. The palladium catalyst was deposited on the photocatalytic titania coating by a photodeposition process at room temperature under UV-light irradiation. The flexible polycarbonate plastic sheet with semitransparent palladium-deposited titania coating works as an optically readable hydrogen gas sensor which can operate at room temperature.

Abstract: Photocatalytic titania coatings loaded with palladium catalyst were prepared onto soda-lime glass substrates by using a low temperature synthesis for application of optical hydrogen gas sensor. Titania coatings were formed on the glass substrate by a sol-gel spin-coating process followed by a hot water treatment at 55°C. Metallic palladium nanoparticles were deposited onto the titania coatings, which obtained with addition of poly(ethylene glycol) (PEG) and without PEG after the hot water treatment, by means of a photodeposition technique at room temperature using UV-light irradiation. The whole fabrication process was carried out under atmospheric pressure. The Pd-photodeposited titania coating obtained with addition of PEG after hot water treatment showed higher hydrogen sensing properties than that obtained without PEG.

Abstract: This study was aimed at the development of a new heterogeneous Pd catalyst based on biologically mineralised palladium (Bio-Pd). Desulfovibrio desulfuricans was used to reduce Pd(II) to nanocrystalline Pd embedded in the bacterial surface. In this way the biomass provides support and prevents coalescence of the palladium nanoparticles. Palladised biomass exhibits catalytic activity, which was demonstrated in a range of applications including reduction, oxidation and hydrogenation reactions. Preparation of Bio-Pd under various conditions leads to the formation of a supported palladium catalyst with potentially different catalytic properties according to the preparation method.

Abstract: Nano-scale palladium was bio-manufactured via enzymatically-mediated deposition of Pd(II) from solution. The bio-accumulated metal palladium crystals were processed and applied onto carbon paper and tested as anodes in a proton exchange membrane (PEM) fuel cell for power production. Up to 85% and 31% of the maximum power generation was achieved by Bio-Pd catalysts made using two strains of bacteria, compared to commercial fuel cell grade Pt catalyst. Therefore, it is feasible to use bio-synthesized catalysts in fuel cells for electricity production.