Home – Home – Jornals – Chemistry for Sustainable Development 2020 number 4

Nickel catalysts supported on modified alumina were synthesized, their physicochemical properties and activity in the reaction of autothermal reforming of methane (ATR CH₄) were studied. Regulation of physicochemical and, consequently, functional properties of the samples was performed by the modification of (γ+δ)-Al₂O₃ support with the additives of different composition Ce_1-xM_xO_y (M = Gd, La, Mg; x = 0, 0.2, 0.5, 0.8 and 1; 1 ≤ y ≤ 2) in the amount of 10 mass %. It is shown that Ni/Ce_1-xM_xO_y/Al₂O₃ are mesoporous materials with specific surface area 80 ± 5 m²/g, slightly changing with the variations of the composition of modifying additive. The phases of alumina (γ+δ)-Al₂O₃, fluorite-like solid solution based on СеО₂ with an average crystallite size 9.0 ± 1.5 nm and nickel oxide NiO are present in the catalysts. The average size of NiO particles is varied in the range from 6.0 to 13.5 nm and is determined by the composition of modifying additive, decreasing with an increase of x, and in the following sequence of oxide additives: CeO₂ > MgО > Gd₂О₃ > La₂O₃. The catalysts are capable of self-activation under the ATR CH₄ reaction conditions, and this effect is enhanced in the following row of M: Mg < Gd < La, which is in good correlation with the reducibility of samples. The optimal catalyst Ni/Се_0.5La_0.5O_1.75/Al₂O₃ is revealed, providing the hydrogen yield of 80 % upon 100 % methane conversion at 850 ^oС. The use of the developed catalysts for the energy-effective conversion of natural and associated petroleum gases into the hydrogen-containing gas is promising.