Pt catalyst is preferable for production of hydrogen from methane, methanol oxidation reaction (MOR) and so on, but the high cost is a critical problem. Efforts have focused on the development of novel synthesis methods to produce small-sized and highly dispersed Pt particles with large surface arearecently, while limited works are available on further study.

Researchers with Institute of Process Engineering (IPE) reported an uniform deposition of clump-like Pt nanocrystal aggregations and high electrocatalytic activities in solution with shape-control agent poly(vinyl pyrrolidone) (PVP-60000) on a carbon electrode by pulse electrodeposition.

The results showed that PVP-60000 played a critical role in controlling the morphology and microstructure of Pt nanocatalysts. For Pt nanocatalysts deposited by introducing PVP-60000, their electrocatalytic activities towards methanol oxidation and oxygen reduction are remarkably improved due to the increased active surface area. The morphology of Pt nanocatalysts evolved from spherical clusters to clump-like crystal aggregations with increased active surface area and thus enhanced electrocatalytic activities using PVP-60000 as a shape-control agent.

For understanding the formation mechanism of Pt nanocatalysts, the nucleation and growth process of Pt nanocatalysts has been preliminarily studied by quantitative analysis of current versus time transient response. The nucleation and growth of clump-like Pt crystal aggregations with PVP-60000 followed the three-dimensional nucleation and diffusion-controlled hemispherical growth for a progressive model, which is helpful for forming small-sized nanocrystal aggregations with higher active surface area.

This study promotes the synthesis and the applications of other materials with high active surface area in the electrocatalytic field. The paper was published in Electrochimica Acta.