Friday, December 13, 2019

Economical fuel cell catalyst from thin graphene based platinum films

Fuel cell catalyst
Researchers at the Georgia Institute of Technology, Atlanta, are using ultrathin, graphene supported platinum films to enable fuel cell catalyst with unprecedented catalytic activity and longevity.

Why platinum films used as fuel cell catalyst?

Platinum is one of the most commonly used catalysts for fuel cells because of how effectively it enables the oxidation reduction reaction at the center of the technology. But its high cost has motivated research efforts to find ways to use smaller amounts of it while maintaining the same catalytic activity.

Most platinum-based catalytic systems use the metal’s nanoparticles chemically bonded to a support surface, where surface atoms of the particles do most of the catalytic work, and the catalytic potential of the atoms beneath the surface is never utilized as fully as the surface atoms—if at all.

To prepare their atomically thin films, the Georgia Tech researchers used a process called electrochemical atomic layer deposition to grow platinum monolayers on a layer of graphene, creating samples that had one, two, or three atomic layers. They found that the bond between neighboring platinum atoms in the film essentially combines forces with the bond between the film and the graphene layer to provide reinforcement across the system. That was especially true in the platinum films that were two atoms thick.

New platinum films are potentially long-lasting

Additionally, the new platinum films at that minimum thickness outperformed nanoparticle platinum in the dissociation energy, which is a measure of the energy cost of dislodging a surface platinum atom. The measurement suggests such films could make potentially longer-lasting catalytic
Reference :
Advanced material processing November 2019 Edition
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