Structured Design of Carbon-Coated Monoliths from Oil Palm Waste for Glucose Conversion into 5-Hydroxymethylfurfural

Conventional powdered catalysts for biomass valorization face critical operational limitations regarding recovery and reusability at an industrial scale. To address these challenges, this study developed innovative structured catalysts based on cordierite monoliths coated with carbon derived from oil palm waste, an abundant agricultural byproduct whose improper disposal poses environmental concerns. The carbonaceous layer was functionalized with sulfonic groups and tin (Sn) species to provide synergistic Brønsted and Lewis acid sites. In addition, colloidal silica was incorporated as a binder, significantly improving coating adhesion and homogeneity. Physicochemical characterization confirmed the successful incorporation of sulfonic groups and SnOx species into the carbonaceous material, leading to dual Brønsted/Lewis acidity, with the B/L ratio increasing from 0.05 in AC to 0.07 in AC20p10Sn. Catalytic evaluation showed that the functionalized monoliths exhibited near 100% of glucose conversion with moderate selectivity towards 5-hydroxymethylfurfural (5-HMF). Notably, despite the surface deposition of solid byproducts, the monolithic architecture successfully eliminated complex downstream separation processes. Furthermore, the structured catalyst exhibited excellent stability, maintaining its catalytic performance over five consecutive cycles. This approach provides a sustainable pathway for structured carbon-coated monoliths derived from biomass waste while overcoming the handling bottlenecks of traditional powder systems by improving catalyst recovery, reusability, and scalability.