Catalytic methane decomposition can become a green process for hydrogen production. In the present study, yttria doped nickel based catalysts were investigated for catalytic thermal decomposition of methane. All catalysts were prepared by sol-gel citrate method and structurally characterized with X-ray powder diffraction (XRD), scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) and Brunauer, Emmet and Teller (BET) surface analysis techniques. Activity tests of synthesized catalysts were performed in a tubular reactor at 500 ml/min total flow rate and in a temperature range between 390 degrees C and 845 degrees C. In the non-catalytic reaction, decomposition of methane did not start until 880 degrees C was reached. In the presence of the catalyst with higher nickel content, methane conversion of 14% was achieved at the temperature of 500 degrees C. Increasing the reaction temperature led to higher coke formation. Lower nickel content in the catalyst reduced the carbon formation. Consequently, with this type of catalyst methane conversion of 50% has been realized at the temperature of 800 degrees C. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.