Photocatalysis by zeolites deposited hydrothermally on metal substrates

Date of Completion

January 1991


Engineering, Materials Science




Zeolite coatings have been grown on metal substrates using several different hydrothermal methods. The use of an isolated mother liquor obtained by separating the sol from a Na-Y aged sol-gel partially crystallized at 96$\sp\circ$C for 6 hours was determined to produce Na-Y coatings which adhered well to the metal substrates. A Na-Y coating was synthesized by crystallizing the isolated mother at 96$\sp\circ$C for 12 hours in the presence of a metal substrate. The thickness of these zeolite coatings could be varied between 1$\mu$m to 0.25 mm depending on the amount of isolated mother liquor used in the reaction. During crystallization, zeolite coatings were observed to grow on one side of the substrate due to gravitational effects. Both Na-Y and Na-A coatings can be synthesized. Substrates used were copper, tin, iron, nickel, and platinum, lead, and molybdenum.^ Zeolite coatings and metal substrates were characterized by X-ray powder diffraction, scanning electron microscopy, luminescence spectroscopy, pore size distribution and surface area techniques, and X-ray photoelectron spectroscopy. These spectroscopic techniques were conducted to determine the zeolite phase present and continuity of coating. Zeolite crystals were determined to be intimate contact with the metal substrate.^ The gas phase photocatalytic conversion of isopropyl alcohol to acetone over uranyl exchanged zeolite coatings was found to be dependent on flow rate, lamp power, reaction temperature, and carrier gas. Highest conversion obtained was between 2-3% using oxygen as a carrier gas and conditions of 920 watts and 0.25 ml/sec over a dehydrated Na-Y thick coating on Cu.^ New zeolite coatings were synthesized to develop advanced materials for use in electrochemistry, catalysis, adsorption, optics, sensor applications, semiconducting circuitry, and photocatalysis. ^