Catalytic Activity of Gallium Oxide in Propane Dehydrogenation: Effect of Support and Influence of Lanthanum Doping

Abstract

Catalytic nonoxidative propane dehydrogenation (PDH) is the purposeful and most economical route to propylene production. The development of new PDH catalysts that can compete with existing commercial platinum and chromium catalysts is a major challenge for the progress of this technology. In the present study, GaO_x-based catalysts (Ga₂O₃ in bulk form or deposited on oxide supports such as SiO₂, Al₂O₃, TiO₂, and ZrO₂) were prepared and their catalytic performance in the PDH was examined. It was shown that the activity of the catalysts depends on the support selected. The best results have been obtained with gallium oxide supported on alumina. The catalytic properties of this material were further improved by doping with lanthanum. PDH reaction catalyzed by La–Ga/Al₂O₃ at 600°C at a gas hourly space velocity (GHSV) of 7500 mL h⁻¹ \({\text{g}}_{{{\text{cat}}}}^{{ - 1}}\) (propane/N₂ = 1/10) provided ca. 30% propane conversion with 95% propylene selectivity. The effect of the La-doping on the properties of bulk and supported Ga₂O₃ were therefore studied by XRD, Raman and ATR-FTIR spectroscopies, HR-TEM, and low-temperature nitrogen adsorption techniques, which showed that La-doping contributes significantly to dispersion of gallium, diminishes crystallinity of the alumina support and increases the specific surface area of the catalyst.