MnO–Co@Pt nanowires encapsulated in N-doped porous carbon derived from MOFs for efficient electrocatalytic methanol oxidation reaction

Abstract

Pt-based catalysts play a significant role in the advancement of direct methanol fuel cells (DMFCs). However, their inefficient reaction kinetics, low resistance to CO poisoning, and unstable performance hinder the commercialization of DMFCs. To address these issues and enhance both the catalytic efficiency and stability of Pt-based catalysts for the methanol oxidation reaction (MOR), in this work MnO–Co@Pt nanocomposites were prepared by encapsulating them into N-doped porous carbon (NPC), which was confirmed through physicochemical characterizations, such as HR-TEM, XRD, and XPS. The catalyst structures were controllably synthesized by adjusting the calcination temperature and reaction time of galvanic replacement. MnO–Co@Pt NPCs demonstrated significantly improved performance compared to Pt/C catalysts for the MOR. The mass activity of 925.72 mA mg_Pt⁻¹ and current density after a 3600 s I–t test of MnO–Co@Pt NPC 800 15 min 15% were 3.3 times and 3.8 times higher than those of the Pt/C catalyst, respectively. The peak potential of CO electrooxidation exhibited a negative shift of 73 mV when compared with the Pt/C catalyst. The exceptional MOR performance of MnO–Co@Pt NPCs can be attributed to the binding and encapsulation effects of the NPCs, which facilitate the isolation, preventing the sintering and expansion of MnO–Co@Pt nanoparticles. This study not only presents a simple method for developing low Pt nanostructures but also offers possibilities for designing nanocomposites with carbon protection layers and coated catalysts incorporating different transition metals. These advancements significantly improve the performance of Pt-based electrocatalysts for the MOR process.