A nickel-magnesia solid solution Ni-Mg-O was examined as a catalyst for solar CO2 reforming of methane. The activity was tested in a laboratory-scale transparent (quartz) reactor under direct irradiation of the catalyst by high-flux visible light from a sun-simulator. The 8-11 wt % Ni-Mg-O catalyst gave the high reforming activity or about 100% of chemical conversion, with little coking, under a high-flux irradiation of 890 kW m(-2) and at a short residence time of about 0.15 s while passing a 1:1 CH4-CO2 gas mixture at 1 atm. The comparison of the activity data with those obtained in a light-irradiated, nontransparent (steel) reactor showed that the intensification of heat supply by the direct light irradiation of the Ni-Mg-O catalyst leads to considerable reaction rate enhancement. Applying this Ni-Mg-O catalyst, a new type of "catalytically activated" ceramic (alumina) foam absorber was prepared and tested on activity in a laboratory-scale volumetric receiver-reactor using the sun-simulator. This new absorber may be applied in solar receiver-reactor systems for converting concentrated solar high fluxes to chemical fuels via endothermic natural-gas reforming.