Acetone–Butanol–Ethanol Catalytic Upgrading into Aromatics over Ga-Modified HZSM-5 Zeolites

The selective conversion of the acetone–butanol–ethanol (ABE) mixture derived from biomass to high-valuable chemicals has attracted intensive attention, while controlling the product selectivity at high ABE conversions is still a challenge. Herein, a bifunctional Ga/HZSM-5 zeolite containing both Brønsted acid sites and Lewis acid sites was designed and utilized as a robust catalyst for the conversion of the ABE mixture to aromatics with a state-of-the-art aromatics yield of 77%. The reaction mechanisms including the aromatics formation and catalyst deactivation were investigated through the catalytic modulation experiments with monocomponents and bicomponents of the ABE mixture and several complementary spectroscopic approaches. A synergistic catalysis between the Lewis acidic Ga species and Brønsted acid sites was proposed, and the structure–activity relationship was established. These results provide some fundamental guidelines to rationally design highly efficient catalysts for the selective catalytic conversion of ABE fermentation.