The comparative study of electrical, optical and catalytic properties of Co_3O_4 thin nanocrystalline films prepared by reactive high-power impulse and radio frequency magnetron sputtering

摘要

This paper deals with the investigation of optical and electrical properties of Co3O4. Their impact on catalytic activity in ethanol dehydrogenation is observed. The change in conductivity is provided by intentionally heating the samples in-situ, variation of oxygen flow rate, introduction of the forming gas (10% H-2 in N-2) and the application of different deposition regimes. Pure Co3O4, as well as deposited catalysts under a forming gas atmosphere are studied. The deposition of the samples on glass and stainless steel substrates is carried out by means of magnetron sputtering. Both radio-frequency and high power impulse magnetron sputtering deposition technologies are applied. By means of these deposition regimes we managed to obtain films with different conductivity and crystalline structure. The morphology of the films is studied by scanning electron microscopy. The crystalline structure and the surface chemical composition of Co3O4 are investigated using X-ray diffraction and X-ray photoelectron spectroscopy. Electrical and optical properties of catalysts are studied by resistance and optical spectroscopy measurements. The catalytic activity of the films is tested on the reaction of ethanol dehydrogenation by means of selected ion flow-drift tube mass spectrometry.