Thermochemical Activation of Wood with NaOH, KOH and H₃PO₄ for the Synthesis of Nitrogen-Doped Nanoporous Carbon for Oxygen Reduction Reaction

Abstract

Carbonization of biomass residues followed by activation has great potential to become a safe process for the production of various carbon materials for various applications. Demand for commercial use of biomass-based carbon materials is growing rapidly in advanced technologies, including in the energy sector, as catalysts, batteries and capacitor electrodes. In this study, carbon materials were synthesized from hardwood using two carbonization methods, followed by activation with H3PO4, KOH and NaOH and doping with nitrogen. Their chemical composition, porous structure, thermal stability and structural order of samples were studied. It was shown that, despite the differences, the synthesized carbon materials are active catalysts for oxygen reduction reactions. Among the investigated carbon materials, NaOH-activated samples exhibited the lowest Tafel slope values, of −90.6 and −88.0 mV dec–1, which are very close to the values of commercial Pt/C at −86.6 mV dec–1.

Keywords

• activated carbons
• pyrolysis
• hydrothermal treatment
• nitrogen doping
• ORR
• fuel cells