Carbon-Supported Cobalt Nanoparticles via Thermal Sugar Decomposition as Efficient Electrocatalysts for the Oxygen Evolution Reaction

The sustainable fabrication of a cobalt (Co) dispersion in carbon (C) via the thermal decomposition of a sugar-based biomass with an abundant Co precursor is successfully synthesized. A foamlike architecture (Co-foam) is first generated from thermally treated sugar in the presence of Co as a catalyst. Co embedded in C (Co/C) is obtained by following a pyrolysis process. The material properties are extensively characterized and indicate a well dispersion of Co species (metallic and nanoparticles) in the C matrix. The developed material is successfully applied as a potential electrocatalyst for the oxygen evolution reaction (OER). The optimized synthesis conditions for the electrocatalyst, Co/C-400, provide the best catalytic OER performance, with the lowest overpotential of 310 mV (10 mA·cm^-2) after normalization using the electrochemically active area and a Tafel slope of 73 mV·dec^-1. The high content of metallic Co nanoparticles as active sites, well-dispersed in a C matrix, efficiently promotes reactivity. Compared with the reference material (IrO₂), this developed material demonstrated a high electrocatalytic performance. It is promising because it exists out of nonprecious and abundant precursors. The facile fabrication method is also environmentally friendly because no additives are applied and no toxic and hazardous formations are generated.