1 research outputs found
Influence of sp<sup>3</sup>–sp<sup>2</sup> Carbon Nanodomains on Metal/Support Interaction, Catalyst Durability, and Catalytic Activity for the Oxygen Reduction Reaction
In
this work, platinum nanoparticles were impregnated by two different
techniques, namely the carbonyl chemical route and photodeposition,
onto systematically surface-modified multiwalled carbon nanotubes.
The different interactions between platinum nanoparticles with sp<sup>2</sup>–sp<sup>3</sup> carbon nanodomains were investigated.
The oxidation of an adsorbed monolayer of carbon monoxide, used to
probe electronic catalytic modification, suggests a selective nucleation
of platinum nanoparticles onto sp<sup>2</sup> carbon nanodomains when
photodeposition synthesis is carried out. XPS attests the catalytic
center electronic modification obtained by photodeposition. DFT calculations
were used to determine the interaction energy of a Pt cluster with
sp<sup>2</sup> and sp<sup>3</sup> carbon surfaces as well as with
oxidized ones. The interaction energy and electronic structure of
the platinum cluster presents dramatic changes as a function of the
support surface chemistry, which also modifies its catalytic properties
evaluated by the interaction with CO. The interaction energy was calculated
to be 8-fold higher on sp<sup>3</sup> and oxidized surfaces in comparison
to sp<sup>2</sup> domains. Accelerated Stability Test (AST) was applied
only on the electronic-modified materials to evaluate the active phase
degradation and their activity toward oxygen reduction reaction (ORR).
The stability of photodeposited materials is correlated with the surface
chemical nature of supports indicating that platinum nanoparticles
supported onto multiwalled carbon nanotubes with the highest sp<sup>2</sup> character show the higher stability and activity toward ORR