Ordered Mesoporous Platinum@Graphitic
Carbon Embedded
Nanophase as a Highly Active, Stable, and Methanol-Tolerant Oxygen
Reduction Electrocatalyst
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Abstract
Highly ordered mesoporous platinum@graphitic carbon (Pt@GC)
composites
with well-graphitized carbon frameworks and uniformly dispersed Pt
nanoparticles embedded within the carbon pore walls have been rationally
designed and synthesized. In this facile method, ordered mesoporous
silica impregnated with a variable amount of Pt precursor is adopted
as the hard template, followed by carbon deposition through a chemical
vapor deposition (CVD) process with methane as a carbon precursor.
During the CVD process, in situ reduction of Pt precursor, deposition
of carbon, and graphitization can be integrated into a single step.
The mesostructure, porosity and Pt content in the final mesoporous
Pt@GC composites can be conveniently adjusted over a wide range by
controlling the initial loading amount of Pt precursor and the CVD
temperature and duration. The integration of high surface area, regular
mesopores, graphitic nature of the carbon walls as well as highly
dispersed and spatially embedded Pt nanoparticles in the mesoporous
Pt@GC composites make them excellent as highly active, extremely stable,
and methanol-tolerant electrocatalysts toward the oxygen reduction
reaction (ORR). A systematic study by comparing the ORR performance
among several carbon supported Pt electrocatalysts suggests the overwhelmingly
better performance of the mesoporous Pt@GC composites. The structural,
textural, and framework properties of the mesoporous Pt@GC composites
are extensively studied and strongly related to their excellent ORR
performance. These materials are highly promising for fuel cell applications
and the synthesis method is quite applicable for constructing mesoporous
graphitized carbon materials with various embedded nanophases