Functionalized Nanocellulose/Multiwalled Carbon Nanotube Composites for Electrochemical Applications

Funding Information: This work was a part of the Academy of Finland?s Flagship Programme under projects nos. 318890 and 318891 (Competence Center for Materials Bioeconomy, FinnCERES). The authors acknowledge the provision of facilities by Aalto University Bioeconomy and OtaNano?Nanomicroscopy Center (Aalto-NMC) and RawMatters research infrastructure (RAMI). Publisher Copyright: ©Four different types of crystalline and fibrillar nanocellulosic materials with different functional groups (sulfate, carboxylate, amino-silane) are produced and used to disperse commercial multiwalled carbon nanotubes (MWCNT). Aqueous nanocellulose/MWCNT dispersions are drop-cast on tetrahedral amorphous carbon (ta-C) substrates to obtain highly stable composite electrodes. Their electrochemical properties are studied using cyclic voltammetry (CV) measurements with Ru(NH3)62+/3+, IrCl62-/3- redox probes, in electrolytes of different ionic strengths. All studied nanocellulose/MWCNT composites show excellent stability over a wide potential range (-0.6 to +1 V) in different electrolytes. Highly anionic and more porous fibrillar nanocellulosic composites indicate strong electrostatic and physical enrichment of cationic Ru(NH3)62+/3+ in lower-ionic-strength electrolytes, while lesser anionic and denser crystalline nanocellulosic composites show no such effects. This study provides essential insights into developing tailorable nanocellulose/carbon nanomaterial hybrid platforms for different electrochemical applications, by altering the constituent nanocellulosic material properties.Peer reviewe