Methane activation with nitrous oxide over bimetallic oxide Ca-lanthanide nanocatalysts

Bimetallic calcium-lanthanide oxides (Ln = La, Ce, Sm, Gd, Yb) were tested for the first time as catalysts in the oxidative coupling of methane (OCM) using nitrous oxide as oxidant. The reaction main products were C2 hydrocarbons. The best results were those obtained with bimetallic calcium-lanthanum and calcium-samarium oxides that achieve hydrocarbons yields comparable to the best reported in the literature using O2 as oxidant. The catalytic performance is clearly dependent of an interaction between calcium and f block element due to calcium ions incorporation on the lanthanide oxide matrix (except for CeO2) that renders oxygen less labile and increases hydrocarbons production. The other main factor that correlate with the variation of the activity and selectivity along the lanthanide series is the catalysts basic properties that increases hydrocarbon production. The catalysts present also an unusual and long stability in the gaseous stream.