Ni-γ-AL2O3 catalysts for obtaining nanocarbon by decomposition of natural gas

Abstract

γ-Al₂O₃ was synthesized by the Sol–gel method, Ni (NO₃)₂ was placed in the pores by the impregnation method, and Ni-γ-Al₂O₃ was obtained by pyrolysis in a hydrogen stream in a CVD device. By the method of chemical vapors phase deposition (CVD) on Ni-Al₂O₃ catalytic converter with decomposition of methane in the natural gas produced carbon nanotubes (CNT) (Chunduri et al. in Mater Express 4(3):235–241, 2014; Zhou et al. in Appl Catal B 208:44–59, 2017). The catalytic activity of the catalysts in methane decomposition was examined from 650?°C to 900?°C by the method of chemical vapors phase deposition (CVD), the yield of CNTs tends to increase with the growth at the ratio of natural gas supply to hydrogen. The specific surface increases with an increase of nickel content and can reach 265.5 m²/g for a sample of 2% Ni-A1₂O₃ at 850?°C. Growth at the temperature of methane decomposition leads to reduction in its specific surface. It has been established that the use of the Ni-Cu/γ-Al₂O₃ catalytic system, in which copper acts as a stabilizing additive, makes it possible to double the maximum yield of the carbon product during the decomposition of natural gas.