Controlled Fabrication of Pt Nanocauliflowers on PEDOT Support and Their Superior Electrocatalytic Activity of Methanol Oxidation Reaction

Fabrication of nanoparticles catalyst materials is an active area of research for high impact in chemical(electro-) catalytic reactions and sensors. Particular emphasis has recently been located on the development of advanced catalysts and electrode materials for fuel cells.  Fuel cell plays an exact alternative for the current scarcity in the petroleum needs in industrial and other applications. But the main problem is the commercialization of fuel cell catalysts because the usage of precious Pt metal catalyst and very low abundance in the earth crust. The galvanic replacement (GDR) approach in which sacrificial metals are replaced with more noble metals has received important attention. Significantly, it minimizes the amount of precious metal required to create an effective electrocatalysts. Recent research efforts [1-5] have been focused on the preparation of Pt nanoparticles with various metallic or bimetallic core-shell nanostructures on support like carbon, dendrimer, metal oxides etc., by GDR. But no reports on conducting polymer support like poly 3,4-ethylenedioxythiophene, PEDOT.

To reduce the usage of Pt catalyst in (monolayer(s) of Pt catalyst) DMFC or PEMFC, galvanic displacement reaction technique was chosen for the decoration of Pt nanocatalyst in PEDOT (Scheme). Non-precious metal nanoparticles such as Cu and Co were electrochemically deposited on PEDOT and were galvanically replaced by Pt nanoparticles as monolayer coverage.

Formation of Pt nanocauliflowers on nanofibrillar morphology of PEDOT support was found to be an alternative to carbon support.

Various loading (14.91µg/cm², 26.85 µg/cm², 32.51µg/cm², 34.93µg/cm², and 42.10µg/cm²) of Pt monolayer(s) were achieved on PEDOT and tested for electrocatalytic activity of methanol oxidation reaction (MOR) (Fig.1C). MOR was found to be enhanced by six orders of magnitude compared to direct deposition of Pt nanoparticles. SEM results clearly indicate the formation of Pt nanocauliflowers on nanofibrillar morphology of PEDOT (Fig.1B). Other characterizations like FT-IR, XRD and AFM were carried out to confirm the interactions of Pt nanocatalysts with polymer matrices, Pt facets, surface morphology and synergistic effect of catalyst support.  Further, TEM results confirm the size of Pt nanoparticles in the range of 8-30 nm. Fabrication of Pt nanocatalysts on PEDOT by GDR of Cu has superior electrocatalytic performance of MOR. This Pt nanocauliflower-PEDOT catalyst will provide additional option to design and fabrication of catalysts for DMFC/PMFC.

References

 

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