Confined platinum nanoparticle in carbon nanotube: structure and oxidation.

A supported nanoparticle is dynamic in reaction conditions, but how this dynamic behavior is influenced by the support remains elusive. Using the stochastic surface walking global optimization method, herein, we report the structure, thermodynamics and catalytic properties of Pt nanoparticles inside and outside a carbon nanotube (CNT). We reveal that confined metal nanoparticles are, surprisingly, structurally more flexible at low temperatures but less likely to melt at high temperatures. By investigating the O2 interaction with a Pt15 cluster inside and outside the CNT, we find that the low temperature structure versatility facilitates the in situ creation of favorable reaction sites, and thus maintains the catalytic activity of O2 dissociation. The decrease of the population for the liquid-like structures (largely disordered) offers the higher stability of the confined nanocatalyst. The theoretical results are consistent with experimental findings for the enhanced antioxidation ability of the confined metal nanoparticles.