Highly Charged Cellulose Nanocrystals via Electrochemical Oxidation

Due to their exceptional properties, cellulose nanocrystals (CNCs) have been proposed for various applications in sustainable materials science. However, state-of-the-art production methods suffer from low yields and rely on hazardous and environmentally harmful chemicals, representing a bottleneck for more widespread utilization of CNCs. In this study, we present a novel two-step approach that combines previously established HCl gas hydrolysis with electrochemical TEMPO oxidation. This unique method allows the collection of easily dispersible CNCs with high carboxylate contents in excellent overall yields of 71%. The electromediated oxidation was conducted in aqueous conditions without the usually required cocatalysts, simplifying the purification of the materials. Moreover, the proposed process is designed for facile recycling of the used reagents in both steps. To evaluate the sustainability and scalability, the environmental impact factor was calculated, and a cost analysis was conducted.