Construction of a stable biochar-supported amorphous aluminum solid acid catalyst with Brønsted-Lewis dual acid sites...

The development of sustainable catalysts for the efficient conversion of biomass to desirable chemicals is significant and challenging. Herein, a stable biochar (BC)-supported amorphous aluminum solid acid catalyst with Brønsted-Lewis dual acid sites was constructed through one-step calcination of a mechanical activation (MA)-treated precursor (starch, urea, and Al(NO₃)₃). The as-prepared N-doped BC (N-BC)-supported Al composite (MA-Al/N-BC) was used for the selective catalytic conversion of cellulose to produce levulinic acid (LA). MA treatment promoted uniform dispersion and stable embedding of Al-based components in the N-BC support with nitrogen- and oxygen-containing functional groups. This process provided the MA-Al/N-BC catalyst with Brønsted-Lewis dual acid sites and improved its stability and recoverability. When the MA-Al/N-BC catalyst was used under optimal reaction conditions (180 °C, 4 h), it achieved a cellulose conversion rate of 93.1% and a LA yield of 70.1%. Additionally, it also showed high activity for catalytic conversion of other carbohydrates. The results of this study offer a promising solution for the production of sustainable biomass-derived chemicals through the use of stable and eco-friendly catalysts.