Steam reforming and oxidative steam reforming for hydrogen production from bioethanol over Mg_2AlNi_xH_zO_Y nano-oxyhydride catalysts

摘要

Mg(2)AlNi(X)H(Z)O(Y )nano-oxyhydrides formation is evidenced during pre-treatment in H-2 at 450 degrees C of Mg2AlNiXOY nano-compounds leading to highly performant catalysts in ethanol conversion and H-2 formation, particularly at low temperature, through catalytic steam reforming (SRE) and oxidative steam reforming (OSRE). Total conversion of ethanol is obtained in SRE and OSRE with high stability. A higher production of H-2 (60 L h(-1) g(cat)(-1)) can be achieved at a reaction temperature of 300 degrees C in OSRE conditions compared to SRE (10 L h(-1) g(cat)(-1) ) mainly because of a beneficial use of a high concentration of ethanol (14 mol %) in presence of O-2 . Moreover, carbon formation is decreased and a much lower input of energy of 50 degrees C is used to get a temperature of 300 degrees C when O-2 is added. Different physico-chemical characterizations and in particular in H-2 (TPR, H-2-XRD, INS) and after tests allow to conclude that the presence of Ni2+ cations in strong interaction with other cations, anionic vacancies and hydride species on and inside the solid play an important role in the catalytic performance (conversion and selectivity) and stability. (C)2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.