RESUMEN
Herein we present the first example of a glycol-coordinated ε-Keggin Al13 chloride (gl-ε-Al13), which is the first chelated version since discovery of Al13 in 1960. The molecular structure consists of [AlO4Al12(OH)12(OC2H4OH)12]Cl7·H2O units with chelating mono-anionic ethylene glycol units replacing one bridging and one terminal oxygen site.
RESUMEN
Aqueous-phase reforming of ethylene glycol over alumina-supported Pt-based catalysts is reported. Performance of the catalysts is investigated by conducting kinetics and in situ attenuated total reflectance (ATR)-IR spectroscopic analysis. Pt/γ-Al2 O3 is unstable under APR conditions (270 °C, 90 bar) and undergoes phase transformation to boehmite [AlO(OH)]. This conversion of alumina is studied in situ by using ATR-IR spectroscopy; transition into boehmite proceeds even at milder conditions (210 °C, 40â bar). Pt/γ-Al2 O3 deactivates irreversibly because the Pt surface area decreases owing to an increasing metal particle size and coverage with boehmite. However, Pt supported on boehmite itself shows stable activity. Surprisingly, the rate of formation of hydrogen per Pt surface atom is significantly higher on boehmite compared to an alumina-supported catalyst. This observation seems correlated to both increased concentration of surface OH groups as well as to enhanced oxidation of Pt when comparing Pt/γ-Al2 O3 with Pt/AlO(OH).