Ruthenium/nickel ex-solved perovskite catalyst for renewable hydrogen production by autothermal reforming of ethanol

Abstract

Ruthenium/nickel ex-solved perovskite catalysts have been synthesized by incipient impregnation. As-synthesized and spent catalysts have been characterized by XRD, TPR-H2, SEM-EDX and TEM analyses. Reduced catalysts have been tested in the autothermal reforming of ethanol, in the temperature range of 600–800 °C. All tested catalysts gave the total conversion of ethanol in the range of investigated temperatures, confirming the oxidative ability and oxygen storage capacity of perovskite, that promotes the catalyst activation. The highest hydrogen yield (83%) is obtained by ruthenium/nickel ex-solved perovskite containing the 0.5 wt% of Ru (SFMN/0.5Ru catalyst) at 600 °C. Increasing the amount of Ru in the catalyst an inhibiting effect is observed: high Ru content modifies the metal species and their reducibility. H2 yield strongly decreases (lower than the 50%) for the catalyst containing the 1 wt% of ruthenium (SFMN/1Ru catalyst), at all the reaction temperatures tested. At 600 °C, were the highest H2 yield is registered, the coke deposition increases with this order: SFMN/1Ru< SFMN/0.5Ru< SFMN, confirming the positive role of noble catalyst toward the inhibition of carbon species formation. By comparison of all catalytic aspects (ethanol conversion, hydrogen yield, coke deposition and stability) the catalyst showing the best performance is ruthenium/nickel ex-solved perovskite with 0.5 wt% of Ru content (SFMN/0.5Ru).