Study on the promotion of FeOx species on water-gas shift reaction in methanol aqueous phase reforming over PtFe/Al2O3 catalyst

Hydrogen production by catalytic aqueous phase reforming (APR) of biomass-derived oxygenates is a promising route to produce hydrogen in a renewable way. As the typical APR catalyst, Pt/Al 2 O 3 is confronted with high methanation activity that consumes H 2 and produces undesired CH 4 during the treatment of methanol solution. In contrast, WGS reaction is the main pathway to boost H 2 generation during APR process. In this work, a series of PtFe/Al 2 O 3 catalyst with different Fe contents were prepared, characterized and tested for the methanol APR reaction. XRD , TEM, XPS and H 2 -TPR technologies were applied to study the change of physicochemical properties with the addition of iron. The restriction on methanation and promotion on WGS reaction were proved as well. With the increase of Fe content, the interaction between Pt and FeO x species have both positive and negative effects on APR reactivity while the CH 4 selectivity descending continuously from 9.25% to as low as 0.60%. Besides, the effects of reduction temperatures (250–350 °C) of Pt0.5Fe/Al 2 O 3 catalyst on APR performances were also investigated. An “Oxygen dynamic transfer cycle” between H 2 O/CO∗ and FeO x species with oxygen vacancies is proposed and verified. This indirect WGS reaction through lattice oxygen on FeO x species that boosting WGS reactivity helps improving H 2 selectivity in the gas products of methanol APR.