Multifunctional Pd/CCS-Cu-MOF Microcapsule Catalyst: A Biomimetic Design Inspired by Metalloenzyme Structures for Sustainable Glycerol Valorizing into Glycerol Carbonate

Glycerol, a key byproduct generated during biodiesel production, has accumulated in excess, hindering the industry's development. A novel palladium-loaded chitosan-copper metal-organic framework (Pd/CCS-Cu-MOF) biomimetic catalyst was developed to valorize glycerol efficiently. Mimicking metalloenzyme structures, this catalyst significantly enhances catalytic performance by controlling the chitosan crosslinking sequence and the active sites' electronic environment. The crosslinked chitosan improves copper's electronic control and forms a microcapsule structure that stabilizes active sites and optimizes reactant mass transfer. Pd/CCS-Cu-MOF achieves a yield of approximately 90% and a selectivity of 99% in the oxidative carbonylation of glycerol. ICP analysis reveals that the catalyst maintains high efficiency with a remarkably low palladium loading of only 0.49wt.%, thereby reducing precious metal use and promoting green chemistry principles. Characterization further demonstrates the microcapsule structure's advantages in enhancing thermal stability, mechanical strength, and pore distribution, providing new insights into natural polymer-metal organic framework composite catalysts. In conclusion, this study offers an efficient, green catalyst for glycerol valorization and opens new avenues for sustainable catalytic technology development, laying a foundation for future industrial applications.