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

Abstract

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 (IrO 2 ), 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.

Strong Co–O Hybrid Polyporous CoOx with High Intrinsic Activity for Outstanding Alkaline OER Performance

“…Impedance tests were carried out at a voltage of 0.7 V (vs Hg/ HgO). The specific surface area of the electrochemical activity (ECSA) was determined by calculating the double-layer capacitance at various sweep speeds (10,20,30,40, and 50 mV s −1 ). The Tafel slope was obtained by converting and fitting the LSV data acquired before.…”

“…At present, thermal decomposition coating technology is mainly used to prepare electrodes in industry, but this method has rarely been reported in the preparation process of Co-based oxide catalysts. Most methods simply involve the thermal decomposition step and do not go through the entire preparation process. , most of the methods are not integrated design but also need to make the catalyst into an ink coating on the substrate surface. − This will reduce the adhesion of the catalyst to the electrode substrate, which greatly affects the overall conductivity, stability, and service life of the electrode. At the same time, the optimization of precursor solvents, which is critical to thermal decomposition coating technology, is rarely studied.…”

“…Most methods simply involve the thermal decomposition step and do not go through the entire preparation process. 39,40 most of the methods are not integrated design but also need to make the catalyst into an ink coating on the substrate surface. 40−42 This will reduce the adhesion of the catalyst to the electrode substrate, which greatly affects the overall conductivity, stability, and service life of the electrode.…”