Selective and Stable Non-Noble-Metal Intermetallic Compound Catalyst for the Direct Dehydrogenation of Propane to Propylene

Abstract

A non-noble intermetallic compound catalyst consisting of Ni₃Ga nanoparticles supported on Al₂O₃ that exhibits high selectivity (∼94%), comparable activity (TOF = 4.7 × 10^-2 s^-1), good stability (∼94% to 81% over the 82 h test), and regenerability in the direct dehydrogenation of propane to propylene at 600 °C has been developed. Through synthesis techniques that stabilize the Ni₃Ga phase, the surface composition of the catalytic nanoparticles could be tuned by Ni and Ga loading such that improved selectivity toward propylene may be achieved. Comparisons with well-defined silica-supported Ni₃Ga and NiGa catalysts and Ni₃Ga/Al₂O₃ with a range of Ni:Ga loading suggested that a specific surface composition range was most promising for propylene production. The presence of Ni at the active particle surface was also found to be critical to drive dehydrogenation and enhance conversion, whereas the presence of Ga was necessary to attenuate the reactivity of the surface to improve selectivity and catalyst stability.