Enhanced Stability of Immobilized Platinum Nanoparticles through Nitrogen Heteroatoms on Doped Carbon Supports

Catalysts in the form of dispersed platinum nanoparticles (Pt NPs) immobilized on carbon usually suffer from deactivation through sintering under reaction conditions. In this contribution, we report the enhanced stability of highly dispersed Pt NPs on surface-modified carbon nanotubes (CNTs) against thermal and electrochemical sintering by N heteroatoms in the N-doped carbon support. The improved antisintering property of Pt NPs under thermal condition is characterized by in situ transmission electron microscopy (TEM), while the stability in electrochemical methanol oxidation reaction (MOR) is further examined at identical location (IL) using an advanced IL-TEM technique. A correlation of the Pt NP growth with the electrochemical surface area (ECSA) and the mass activity in MOR has been inferred. Our results indicate that both the surface oxygen groups and nitrogen-doped species are responsible for the fine dispersion of Pt NPs on the surface-modified CNTs, while the Pt NPs can be effectively stabilized under thermal and electrochemical conditions through the strong metal–support interaction via N heteroatoms. We further reveal that the mass activity of Pt NP is closely associated with the ECSA rather than directly affected by N-doping to CNTs.