Ni/MgO–Al2O3 and Ni–Mg–O catalyzed SiC foam absorbers for high temperature solar reforming of methane

Ni catalyst supported on MgO–Al₂O₃ (Ni/MgO–Al₂O₃) prepared from hydrotalcite, and Ni–Mg–O catalyst are studied in regard to their activity in the CO₂ reforming of methane at high temperatures in order to develop a catalytically activated foam receiver–absorber for use in solar reforming. First, the activity of their powder catalysts is examined. Ni/MgO–Al₂O₃ powder catalyst exhibits a remarkable degree of high activity and thermal stability as compared with Ni–Mg–O powder catalyst. Secondly, a new type of catalytically activated ceramic foam absorber – Ni/MgO–Al₂O₃/SiC – and Ni–Mg–O catalyzed SiC foam absorber are prepared and their activity is evaluated using a laboratory-scale receiver–reactor with a transparent quartz window and a sun-simulator. The present Ni-based catalytic absorbers are more cost effective than conventional Rh/γ-Al₂O₃ catalyzed alumina and SiC foam absorbers and the alternative Ru/γ-Al₂O₃ catalyzed SiC foam absorbers. Ni/MgO–Al₂O₃ catalyzed SiC foam absorber, in particular, exhibits superior reforming performance that provides results comparable to that of Rh/γ-Al₂O₃ catalyzed alumina foam absorber under a high flux condition or at high temperatures above 1000 °C. Ni/MgO–Al₂O₃ catalyzed SiC foam absorber will be desirable for use in solar receiver–reactor systems to convert concentrated high solar fluxes to chemical fuels via endothermic natural-gas reforming at high temperatures.