High-Performance Fenton-like Catalysis through Metal-Organic Framework-Derived Nanoporous Carbons for Continuous Cleavage of Polysaccharides.

Abstract

Polysaccharides, one of the most abundant biomolecules in nature, exhibit structural complexity owing to variations in molecular weight, branching, and methyl-esterification, posing challenges for understanding their structure-activity relationships and direct application. Degradation of polysaccharides into oligosaccharides is of magnitude significance for both top-down preparation of functional oligosaccharides for easier utilization and subsequent polysaccharide sequencing to understand their biological activity basis. Due to its mildness and universality, the Fenton reaction facilitates the preparation of oligosaccharides, yet the low utilization efficiency of hydrogen peroxide leading to low activity has been a persistent constraint. Here, we report a metal-loaded nanoporous carbon heterogeneous catalyst derived from metal-organic frameworks that can efficiently convert hydrogen peroxide into hydroxyl radicals while maintaining low metal leaching (<0.05 μg/mL). The catalyst features stable transition metal oxide active centers, along with defects, vacancies, and functional modifications, significantly enhancing the degradation rate from 8.49% to 94.11%, enabling over 50 cycles of catalytic degradation. This catalyst facilitates a cascade of Haber-Weiss reactions and Cu-mediated Fenton reactions, realizing sustained degradation at room temperature. Furthermore, a Fenton reactor with this catalyst was constructed to achieve continuous production of oligosaccharides, and it was connected in series with liquid chromatography-mass spectrometry (LC-MS/MS) to achieve rapid sequencing of oligosaccharides, offering high sensitivity, resolution, and throughput of oligosaccharide structure compared to the homogeneous Fenton degradation system. This work has developed a universal method for polysaccharide degradation, providing a powerful platform for the preparation of high-activity intermediate oligosaccharides.