Triple-junction interfacial engineering Pt–CeO₂/three-dimensional nitrogen-doped carbon frameworks electrocatalysts for methanol oxidation reaction

Efficient Pt-based catalysts towards anodic methanol oxidation reaction (MOR) is crucial to direct methanol fuel cells (DMFCs). Pt-based catalysts with triple-junction interfaces of Pt, metal oxidizes (MO_x) and carbon materials have broad engineering prospect due to the synergistic effect among different composites. However, in Pt-MO_x/carbon material catalysts reported previously, Pt and MO_x nanoparticles (NPs) are too large and the triple-junction interfaces are insufficient. Herein, we innovatively introduce oxidized carbon nanotubes (OCNTs) into nitrogen-doped reduced graphene oxide (NrGO) sheets and propose a cost-efficient self-assembly process for the construction of three-dimensional nitrogen-doped carbon frameworks (NrGO-OCNTs). Furthermore, a modified solvothermal method is developed to uniformly deposit ultrafine Pt and CeO₂ NPs onto NrGO-OCNTs so that sufficient Pt–CeO₂–C triple-junction interfaces can be introduced. The obtained Pt–CeO₂/NrGO7-OCNTs3 catalyst with the NrGO/OCNTs ratio of 7:3 shows the optimum electrochemical surface area and mass activity of 154.9 m²·g_Pt⁻¹ and 845 A·g_Pt⁻¹, respectively, which are 2.3 and 3.2 times higher than those of a commercial Pt/C catalyst. It also possesses excellent stability and anti-CO poisoning performance. These improvements may be attributed to the unique architecture of the support and enhanced synergistic effect among Pt, CeO₂ and NrGO7-OCNTs3. This approach is simpler and more efficient than other methods reported previously and suitable for engineering of efficient Pt-based catalysts.