Selective Oxidation of Chitinous Waste via Catalytic C–C Bond Scission: Unlocking a Green Approach For Biomass Upgrading

Catalytic oxidation of biomass waste is a key environmental engineering route for waste valorization. However, it is typically conducted in alkaline media and is often limited by insufficient catalytic activity. Here, we report an efficient strategy for converting shrimp shell (a chitin-rich waste, denoted SS) through selective C–C bond scission over a stable biochar-supported Ru catalyst featuring synergistic Ru-base catalysis. This system affords an acetic acid (AA) yield of 43.2% and 7.6% of 4-hydroxypyridine directly from demineralized SS without adding alkaline media in the oxidation process. The sustainability metrics of this process is evaluated and yield an Environmental Factor (E-factor) of 2.37, highlighting its green superiority over conventional routes. In situ DRIFTS, density functional theory (DFT) calculations, and ESR characterization further reveal that clustered basic sites facilitate H abstraction at the Cα/Cβ positions of sugar intermediates, while RuOx species promote subsequent oxidative C–C bond scission via a Mars−van Krevelen mechanism. A planar adsorption configuration between the reactant and RuOx is identified, which favors C–C bond rupture and enhances reaction efficiency. Kinetic analysis further supports the mechanistic results and reveals that oxidative Cα–Cβ bond cleavage is the rate-determining step. Overall, this work delivers a high-activity and green platform for the selective oxidation of chitinous waste and provides a clue for upgrading solid waste through cooperative catalysis.