A series of PbO-MgO aerogels differing by their atomic Pb/Mg ratios were tested at 720 degrees C for methane coupling using nitrous oxide to ethane and ethylene. The best catalyst (Pb/Mg = 0.5) gave a C-2+ overall selectivity of 69%, a high activity (at W/F = 0.03 g s cm(-3)) and a good stability with time-on-stream. A kinetic study showed that the reaction is of the Rideal-Eley type with nitrous oxide reacting in the adsorbed phase. Other supports such as Al2O3, ZrO2, TiO2 and SiO2 were used and the activities recorded agreed well with the basicity of the catalyst, PbO-SiO2 being totally inactive : MgO > ZrO2 > Al2O3 > TiO2 > > > SiO2.