Comparison of effects of La, Mg and Rh addition on the activity and stability of Ni/SiO2 catalysts in dry reforming of methane at low temperature

Abstract

In this work, a commercial silica nanopowder was used to prepare nickel based catalysts; Ni_x/SiO₂ (x: 5, 10 and 15 wt. percent), bimetallic catalysts Ni₁₀La₁₀/SiO₂ and Ni₁₀Mg₁₀/SiO₂ and rhodium promoted catalysts, Ni₁₀Rh_x/SiO₂ (x: 0.1, 0.225 and 0.5 wt. percent). The catalysts were characterized by N₂ sorption, XRD, HRTEM and TPR and tested in dry reforming of methane at low temperature. NiO_x nanoparticles were of similar diameter for mono and bimetallic samples. Upon the addition of rhodium and after the second calcination, the diameter of NiO increases from 20 to 70 nm. The presence of the second metal (La) near Ni leads to an increase in the activity. When NiO diameter increases, the activity decreases (Ni₁₀Rh_0.1/SiO₂). For the Rh_0.5Ni₁₀/SiO₂, the activity was the higher among the other catalysts. In terms of stability, all the catalysts were stable for 12 hours.