Ni and Co-based catalysts supported on ITQ-6 zeolite for hydrogen production by steam reforming of ethanol.

Ni and Co catalysts supported on ITQ-6 zeolite have been synthesized and evaluated in the steam reforming of ethanol (SRE). Catalysts were also characterized by means of N 2 adsorption-desorption, XRD, H 2 -TPR, and H 2 -chemisorption. ITQ-6 containing Co (Co/ITQ-6) presented a higher conversion of ethanol and production of hydrogen than ITQ-6 containing Ni (Ni/ITQ-6). The lower size of the metallic cobalt particles shown in Co/ITQ-6 seems to be the major responsible of its higher catalytic performance. Regarding the reaction by-products (CO, CH 4 , C 2 H 4 O and CO 2), Co/ITQ-6 showed the lowest selectivity at medium and high temperatures (773 and 873 K). At low reaction temperatures (673 K) the dehydrogenation reaction predominates in the Co/ITQ-6, what it is supported by the high concentration of acetaldehyde detected at this temperature. In the case of the Ni/ITQ-6 the main side reaction at 673 K seems to be the methanation reaction since large concentrations of methane are detected. Stability studies were also carried out showing lower deactivation of Co/ITQ-6 at large reaction times (24 h). Characterization of the exhausted catalysts after reaction showed the presence of coke in both catalysts. Nevertheless, Co/ITQ-6 presented the lowest coke deposition. In addition, Co/ITQ-6 exhibited the lowest metal sinterization, what could be also account for the lower deactivation exhibited by this sample. This fact could be related to the higher interaction between the cobalt metallic particles and the ITQ-6 support as the H 2 -TPR studies demonstrate. • Ethanol steam reforming catalysts based on Co or Ni supported on ITQ-6 zeolite is prepared by the first time. • Higher ethanol conversion and hydrogen selectivity is exhibited by the catalyst with Co. • The lower size of the metal Co particles is the major responsible of its higher catalytic activity. • Higher stability is exhibited by the Co catalyst (lower coke deposition and sinterization of the metallic particles). [ABSTRACT FROM AUTHOR]