The important research topic is the deposition of Co3O4 thin-film catalysts and their characterization. We have focused on the following tasks for these materials. The first task was to improve the properties of chemically prepared catalysts. The second task was to find out and describe the differences between catalysts prepared by high-power impulse magnetron sputtering (HiPIMS) and radio-frequency (RF) magnetron sputtering. The achieved essential research results are summarized below.
The supported catalysts with Co3O4 coatings on stainless steel wire meshes were prepared by the combination of reactive magnetron sputtering and electrochemical deposition (ED). The cathodic reduction of cobalt nitrate in aqueous solution followed by heating of the deposited product resulted in obtaining the Co3O4 catalyst with high activity in the ethanol total oxidation. The coating of stainless steel meshes with Co3O4 thin films by the RF magnetron sputtering or HiPIMS procedures led to increasing of adhesion of Co3O4 added subsequently by the electrochemical deposition but the adhesion of deposited cobalt oxide was further improved significantly when the obtained catalysts were coated with additional Co3O4 thin film by the magnetron sputtering. The RF-ED-RF catalyst prepared by such a way showed the highest specific activity in the ethanol total oxidation and the best Co3O4 adhesion to the support. It was found that catalytic activity of the catalysts prepared by the RF magnetron sputtering is higher than that of the catalysts prepared using the HiPIMS process. The activity of the supported catalysts was strongly affected by the presence of very porous cobalt oxide layer well accessible to the reactants, which was obtained after electrochemical deposition and subsequent heating. The ED catalyst with the highest Co3O4 loading showed the highest efficiency in the total ethanol oxidation. The magnetron sputtering provided relatively compact Co3O4 coatings with lower catalytic activity but these coatings were very important in order to obtain the catalysts with good adhesion to the support. All supported catalysts with Co3O4 coatings on stainless steel meshes were more active in the total oxidation of ethanol to CO2 than the pelletized commercial Co3O4, though the cobalt oxide content in the bed of supported catalysts was nearly 50 times lower. [1], [2].
References:
[1] M. Dvořáková, R. Perekrestov, P. Kšírová, J. Balabánová, K. Jirátová, J. Maixner, P. Topka, J. Rathouský, M. Koštejn, M. Čada, Z. Hubička, F. Kovanda: Preparation of cobalt oxide catalysts on stainless steel wire mesh by a combination of magnetron sputtering and electrochemical deposition, Catalysis Today 334 (2019) 13–23
[2] R. Perekrestov, A. Spesyvyi, J. Maixner, K. Mašek, O. Leiko, I. Khalakhan, J. Maňák, P. Kšírová, Z. Hubička, M. Čada: The comparative study of electrical, optical and catalytic properties of Co3O4 thin nanocrystalline films prepared by reactive high-power impulse and radio frequency magnetron sputtering, Thin Solid Films 686 (2019) 137427.
The plasmatic deposition system of catalytic oxide thin films.
