Upgrading of the Old Pt@Al2O3 Using Al(OH)3 as Alumina Precursors with Remarkable Catalytic Hydrogen Combustion Performance at Room Temperature

This article discloses new Pt@Al2O3 catalysts obtained by incipient wetness impregnation of H2PtCl6 solution on aluminum trihydroxide Al(OH)3 (Bayerite and Gibbsite), active in catalytic hydrogen combustion (CHC) at room temperature, in lean hydrogen reactant flow, without the need of a prereduction step of platinum. This represents a gain in terms of catalyst preparation and safety issues for domestic and industrial applications based on hydrogen combustion. Highly dispersed Pt4+ species were observed by X-ray photoelectron spectroscopy (XPS) by contrast to conventional calcined Pt/Al2O3 catalysts obtained by H2PtCl6 impregnation over γ-Al2O3 or Boehmite which are inactive in CHC at room temperature without prereduction step. It is proposed that the channel structures of Al(OH)3 play a role in the stabilization of Pt4+ species: the pool of bridging acid hydroxyl groups, Al–(OH)–Al, located at the channels’ entrance of the aluminum trihydrate structures might strongly anchor the chloroaluminate anions during the impregnation steps and prevent their segregation during the further drying and calcination steps.