Artificial kink defects enable high-efficiency degradation of nanocellulose via mechanochemical activation

Abstract

High-efficiency degradation and conversion of cellulosic biomass into biofuels and bio-based chemicals are critical to human society for sustainable development. Long-term challenges in deciphering how mechanical external force activates nanocellulose hydrolysis at the molecular level have hindered the wider application of mechanochemistry in high-efficiency degradation technologies. Here, combining multiscale modeling and in situ experimental characterization, we revealed the mechanochemistry hidden in the mechanically activated nanocellulose degradation behaviors, that artificial kink defects enable hydrolysis acceleration. The localized plastic deformation and nonlinear molecular geometry at kink defects drive hydrolysis processes toward the lower-barrier reaction pathway and facilitate hydrolysis accessibility. The proposed two-step mechanochemical hydrolysis strategy, introducing more artificial kink defects and preferential reaction sites via mechanical pretreatment, realizes substantial enhancement of hydrolysis efficiency. This study provides a framework for anticipating how mechanical external force, microstructure defects, and molecular geometric mutation contribute to the mechanochemical degradation of cellulosic biomass with more sustainability and bioeconomy.