(AGENPARL) – LONDON (UNITED KINGDOM), mar 07 luglio 2020
Edge-selectively carboxylated graphene (ECG) is of great importance in potential applications; however, its catalytic activity towards hydrolysis of woody biomasses is not yet emphasized. Herein, we rationally designed two-dimensional ECG nanosheets with tunable COOH content via the direct ball milling of graphite with the assistance of dry ice as active, durable, and cost-effective catalysts for selective hydrolysis of cellulose and lignocellulose. The as-formed ECG is a highly water-dispersible and self-exfoliated two-dimensional crumbed nanosheet with a great surface area of (94.1 m2 g-1) and enriched with an abundant carboxylic group (22.79 %) at the edges. These peculiar structural and compositional merits are endowing the catalytic activity of ECG to hydrolysis cellulose into glucose in a high yield of (87 %) within 20 min at 180 oC in the presence of HCl 120 ppm alongside hydrolysis of eucalyptus lignocellulose to xylose 89 %. Meanwhile, the ECG selectively converted lignocellulose into xylose 98 % in water, owing to layered structure, hydrophilicity, and synergetic effect. The effects of COOH content of ECG catalyst on the adsorption of cellulose and hydrolysis activities towards cellulose and eucalyptus were investigated deeply. The effects of ball-milling pretreatment and sonication on the hydrolysis activity were also benchmarked. The presented study may open new horizons towards the utilization of ECG in the hydrolysis of biomass.
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