Highly Conductive and CO-Resistant Cobalt-Based Monolithic Electrodes for the Catalytic Oxidation of Methanol

To develop active and stable electrocatalysts for the methanol oxidation reaction (MOR), many non-noble metal-based nanomaterials have been explored, which are physically loaded on conductive substrates to form electrodes. During a long-term MOR under high current density, these electrodes usually lose activity due to the aggregation or falling off of active nanomaterials. To overcome these problems, we report a simple strategy to synthesize an active, stable, and carbon monoxide (CO)-resistant monolithic electrode for the MOR: cobalt nanocrystal/nitrogen, oxygen-doped carbon (Co@N,O-C, CP) monolith. CP monolith shows a high electrical conductivity (1.54x10(4) S/cm), which can be directly used as an electrode without any substrate. Co nanocrystals are dispersed uniformly in the N,O-C matrix as the active site for MOR, whereas the N,O-C matrix protects Co nanocrystals and also facilitates the mass and charge transfer between electrolyte and the electrode. The optimized CP-FT-500 electrode presents a high MOR activity of 352 mA/cm(2) at 0.6 V vs SCE (unsaturated calomel electrode) in alkaline electrolyte, which exceeds most previously reported Co-based MOR catalysts. The optimal CP-FT-500 catalyst also presents excellent durability and anti-CO poisoning capability (93.3 % retention of activity), which exceeds that of Pt/C (67.5 % retention). Based on its excellent catalytic activity, stability, and high resistance to CO poisoning, CP-FT-500 catalyst is a promising low-cost catalyst for MOR.

Automated summary

A cobalt nanocrystal/nitrogen, oxygen-doped carbon (Co@N,O-C, CP) monolithic electrode with high electrical conductivity and excellent durability has been developed for the methanol oxidation reaction. This electrode shows superior activity, stability, and resistance to CO poisoning, making it a promising low-cost catalyst for MOR applications.