Ni–Fe, Co–Fe, and Co–Ni nanocomposites based on carbon nanotubes in the reaction of CO2 methanation

Abstract

For effective carbon dioxide (CO2) methanation, bimetallic Co80Ni20/CNTs, Ni80Fe20/CNTs, and Co93Fe07/CNTs nanocomposite catalysts, where subscript numbers indicate the metal content (wt.%), have been prepared with wet impregnation method, further thermal decomposition, and chemical reduction stages using carbon nanotubes (CNTs) as a carrier. The catalysts were characterized using TG, SEM-EDX, argon physisorption, and X-ray powder diffraction methods. The pristine nanotubes demonstrated a slight activity in CO2 conversion due to the presence of small quantity of Ni. Among the tested nanocomposites the bimetallic Ni80Fe20/CNTs catalyst showed improved catalytic activity compared to Co80Ni20/CNTs and Co93Fe07/CNTs. The SEM-EDX analysis showed not uniform distribution of bimetallic aggregates on carbon nanotubes matrix for Ni80Fe20/CNTs and Co93Fe07/CNTs. However, this fact did not affect to catalytic properties of mentioned nanocomposites. Ni80Fe20/CNTs exhibited high activity in the CO2 methanation with 88% of CH4 yield at 350 °С unlike Co93Fe07/CNTs with 64% of CH4 yield.