Study of the catalytic activity of calcined Ni/Mg/Al (Mn) hydrotalcites for N2O decomposition

Abstract

Mixed oxide-based catalysts prepared by thermal decomposition of Ni-(Mg)-M(III) hydrotalcite-like compounds (M(III) = Al, Mn) were used in catalytic decomposition of nitrous oxide in order to describe the catalytic activity of multicomponent catalysts and to study the effect of Mg2+ presence in the catalysts structure. Although the catalytic activity of prepared Ni-Al and Mg-Mn calcined hydrotalcites was high, the simultaneous presence of both transition metal cations Ni2+ and Mn3+ in the catalyst structure caused a decrease of N2O conversion and specific surface area. The N2O conversions decrease with increasing content of Mg in the Ni-Al system and increase in the Ni-Mn system. The rise of Mg content in the catalysts resulted in larger surface area and higher thermal stability of both Ni-(Mg)-Al and Ni-(Mg)-Mn samples. The prepared hydrotalcites as well as calcined products were characterized by the thermal analysis (TG/DTA), powder X-ray diffraction (XRD), and BET surface area measurements.