Catalytic steam reforming of methane under conditions of applicability with Pd membranes over supported Ru catalysts

Three Ru catalysts supported on SiO2, ZrO2–SiO2 and ZrO2–La2O3 have been prepared, characterized and tested in the methane steam reforming (SR) reaction, and for comparative purposes a Ni/SiO2 catalyst has also been studied. Conditions of catalytic studies have been selected for the subsequent application in a hydrogen extraction Pd membrane reactor. That is, reaction temperatures in the range of 400–550 °C and with different amounts of catalyst in order to work under and/or close to the equilibrium conversion conditions. All the supported Ru samples exhibit high catalytic activity and similar CO and H2 yields. Finally these catalysts are fully stable under reaction conditions at 550 °C for 15 h, while the Ni/SiO2 sample suffers a significant deactivation. The main deactivation process affecting this latter catalyst is the carbon deposition of partially dehydrogenated intermediates as detected by Raman spectroscopy. Hence, these Ru catalysts appear to be suitable for application combined with metallic (Pd) membrane.