Preparation and characterization of heterogeneous catalysts by metal-organic chemical vapor deposition
by Leung Yuk Lam Frank
M.Phil. Chemical Engineering
xv, 93 leaves : ill. ; 30 cm
A novel Metal-Organic Chemical Vapor Deposition (MOCVD) technique was developed to prepare heterogeneous metallic supported catalyst. Copper (II) acetylacetonate and activated carbon were chosen as the precursor and the porous support. Nitrogen was used as the carrier gas for the deposition process....[ Read more ]
A novel Metal-Organic Chemical Vapor Deposition (MOCVD) technique was developed to prepare heterogeneous metallic supported catalyst. Copper (II) acetylacetonate and activated carbon were chosen as the precursor and the porous support. Nitrogen was used as the carrier gas for the deposition process.
A new system design was built to achieve higher metal loading within shorter preparation time. In the optimization of system parameters, higher metal loading can be achieved by using longer deposition time, optimum carrier gas flow rate, smaller amount and smaller particle size of the support.
Several techniques were carried out to characterize the catalyst such as Physisorption, X-Ray Diffraction, X-ray Photoelectron Spectroscopy, Inductively Coupled Plasma - Optical Emission Spectroscopy and Scanning Electronic Microscopy assisted with the Energy Dispersive X-ray.
It was found that the B.E.T. specific surface area, total pore volume and total adsorption volume were reduced after deposition. This could be due to the formation of the deposited copper onto the porous media. The status of the deposited copper on Cu/AC could be tuned by using different deposition temperature and the post treatment process of reduction. It was found that higher deposition temperature helps to form crystalline elemental copper structure on the catalyst. The morphology of the cylindrical Cu/AC and sized Cu/AC was analyzed by SEM-EDX. The results show that the metal was deposited onto the inner part of the porous support, although some uneven metal distribution was observed.
Preliminary study was carried out to evaluate the catalytic activity of the developed catalyst in the wet air oxidation of phenol solution. It was found that the catalyst prepared by MOCVD can reduce the leaching problem of the active metal on the support and is able to degrade 70 % of phenol at a temperature of 150°C.