Synergy effects between β and γ phases of bismuth molybdates in the selective catalytic oxidation of 1-butene

Abstract β+γ mixed Bi–Mo–O phases with a large range of composition were prepared by coprecipitation for investigating the existence of synergetic effects between β and γ phases for the oxidative dehydrogenation of 1-butene. Results from surface characterization show that the surface of the catalysts always has a composition similar to the β phase but the γ phase grows around β phase. Mixed phases present higher activity and less CO 2 selectivity than pure β and γ phases. This result leads to propose that the whole catalyst (bulk and surface) participates in the catalytic process. The synergetic effect between these two phases can be ascribed to the high oxygen mobility in the lattice of the γ phase that allow the migration of oxygen species from the γ to the β phase.