High efficient electrocatalytic performance of nitrogen-doped carbon nanosphere-loaded platinum composite in DMFCs

Carbon materials, characterized by their high conductivity, large specific surface area, and stable chemical properties, have been employed as anode catalysts in direct methanol fuel cells (DMFC). However, during the electrocatalysis process, intermediate species like CO may adsorb onto the surface of the carbon support, thereby diminishing the catalyst’s activity. In this study, nitrogen doping technology was leveraged to alter the growth mechanism of carbon spheres, achieving an average particle size of approximately 1 [Formula: see text]m with uniform shape and good dispersion. Nitrogen doping facilitates the homogeneous nucleation of carbon pellets and influences the polymerization and carbonization of carbon precursors, effectively controlling the growth rate and size of the carbon pellets. The resultant nitrogen-doped carbon ball supported platinum (NCB@Pt) composite demonstrated markedly enhanced electrocatalytic performance and stability in the methanol oxidation reaction. For instance, NCB@Pt exhibited a current density of 120 mA ⋅ cm[Formula: see text], a notable increase from the 8.5 mA ⋅ cm[Formula: see text] shown by the undoped carbon nanospheres supported metal-platinum composite (CB@Pt). Furthermore, NCB@Pt displayed an initial potential of −0.7 V, which is superior to CB@Pt’s −0.57 V. Potentiostatic electrochemical testing revealed that NCB@Pt maintains excellent stability during methanol oxidation at room temperature, with a current density reduction of merely 6% after a 3 h reaction. In contrast, CB@Pt experienced a current density decrease of about 53% under similar conditions. These advancements can be ascribed to the fact that nitrogen doping not only boosts the conductivity of the carbon carrier, facilitating charge transport, but also strengthens the interaction between the carbon carrier and platinum, minimizing the aggregation of platinum nanoparticles, exposing more active sites, and curtailing the degradation of catalyst performance. Such findings underscore that refining the carbon support through nitrogen doping constitutes an effective approach to significantly improve the efficacy of DMFC anode catalysts.