A novel strategy for synthesizing Fe, N, and S tridoped graphene-supported Pt nanodendrites toward highly efficient methanol oxidation

Abstract

Multiatom-doped carbon nanomaterials have emerged as very promising electrocatalysts for fuel cell applications because of the synergistic electron effect that occurs between the hetero-dopants. However, their electrochemical properties strongly depend on the structural design of the doped heteroatoms, and a fundamental understanding of their electrocatalytic mechanism is still a challenge. Herein, a novel and effective sulfonated iron phthalocyanine pyrolysis strategy to synthesize Fe, N, and S tri-doped graphene nanohybrids is reported, and this hybrid is utilized as the catalyst support for highly efficient Pt nanodendrites. In this strategy, the incorporation of S atoms is rationally engineered by the sulfonate groups in the phthalocyanine molecules, and it leads to the uniform distribution of an active FeNx-S2 configuration in the graphene structure, along with the Fe and N atoms. The Pt nanodendrites assembled on Fe, N, and S tri-doped graphene exhibit a much higher electrocatalytic activity and long-term electrochemical durability for methanol oxidation. Both controlled experiments and density functional theory calculations reveal that the co-doping of Fe, N, and S atoms is beneficial for the formation of dendritic Pt nanoparticles and the electrochemical performance enhancement of Pt nanodendrites. The density functional theory calculations indicate that the co-doping of Fe, N, and S atoms not only increases the ability to adsorb Pt and the catalyst durability, but also enhances the CO tolerance ability and prevents the poisoning effect during methanol oxidation. This study demonstrates a new method for the controllable synthesis of multi-doped graphene-based electrocatalysts with optimized surface structures and electrochemical performances.