Study of the stability of Pt/SiO2–Al2O3 catalysts in aqueous medium: Application for sorbitol transformation

Sorbitol transformation in aqueous medium can be used to produce alkanes from lignocellulosic sugars over a bifunctional catalyst, usually Pt/SiO2–Al2O3. However, the catalyst is modified by the hydrothermal medium. In this study, the separated effects of water and medium generated during sorbitol transformation reaction on a Pt/SiO2–Al2O3 catalyst have been investigated. Reaction products, in particular acidic ones, also alter catalyst properties. Catalyst pre-treatment by steaming appears to be an interesting way to obtain a catalyst which is less sensitive to liquid water in terms of platinum dispersion and textural properties. Steaming pre-treatment has no impact on selectivity. These investigations provide an incentive for the development of new sorbitol transformation catalysts more suitable under hydrothermal conditions.

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► Platinum sintering is faster in liquid water than in wet air.
► Steaming pre-treatment stabilises the catalyst further put in hydrothermal medium.
► Reaction medium has a stronger impact on catalyst properties than pure water medium.
► Steaming pre-treatment doesn't impact selectivities during sorbitol transformation.