Cellulose-based carbon nanotubes array with lawn-like 3D architecture for oxygen reduction reaction

The conversion of biomass into high-performance carbon-based materials provides an opportunity to valorize biomass for advanced applications. Achieving this necessitates requires dedicated efforts and innovations in biocarbon synthesis, design, and applications. This study proposes the controllable conversion of biomass-derived cellulose into well-distributed carbon nanotubes (CNTs) by tuning the precipitation of cellulose pyrolysis generated vapors with in-situ formed ferric metal nanoparticles. The obtained CNTs exhibited lawn-like 3D architecture with similar length, uniform alignment, and dense distribution. The combined use of ferric chloride and dicyandiamide as the reagents with a mass ration of 0.162:1.05, demonstrated optimal performance in controlling the morphology of CNTs, enhancing the graphitization, and increasing the content of graphitic-N and pyridine-N. This multi-dimensional modification enhanced the electrocatalytic performance of the obtained CNTs, achieving an onset potential of 0.875 V vs. relative hydrogen electrode (RHE), a half-wave potential of 0.703 V vs. RHE, and a current density of -4.95 mA cm^-2 during the oxygen reduction reaction. Following microbial fuel cells (MFCs) tests achieved an output voltage of 0.537 V and an output power density of 412.85 mW m^-2, comparable to MFC with Pt/C as the cathode catalyst. This biomass-derived catalyst is recommended as a high-quality, non-noble metal alternative to traditional noble-metal catalysts.