It is conventionally assumed that the growth of monodisperse colloidal nanocrystals requires a temporally discrete nucleation followed by monomer attachment onto the existing nuclei. However, recent studies have reported violations of this classical growth model, and have suggested that inter-particle interactions are also involved during the growth. Mechanisms of nanocrystal growth still remain controversial. Using in situ transmission electron microscopy, we show that platinum nanocrystals can grow either by monomer attachment from solution onto the existing particles or by coalescence between the particles. Surprisingly, an initially broad size distribution of the nanocrystals can spontaneously narrow. We suggest that nanocrystals take different pathways of growth based on their size- and morphology-dependent internal energies. These observations are expected to be highly relevant for other nanocrystal systems.

Observation of Single Colloidal Platinum Nanocrystal Growth Trajectories

We determined the size-dependent specific and mass activities of the oxygen reduction in HClO(4) solutions on the Pt particles in the range of 1-5 nm. The maximal mass activity at 2.2 nm is well explained based on density functional theory calculations performed on fully relaxed nanoparticles. The presence of the edge sites is the main reason for the low specific activity in nanoparticles due to very strong oxygen binding energies at these sites. Our results clearly demonstrate that the catalytic activity highly depends on the shape and size of the nanoparticles.

http://ma.ecsdl.org/content/MA2011-01/42/1931.full.pdf

Electrocatalysis on Platinum Nanoparticles: Particle Size Effect on Oxygen Reduction Reaction Activity

1,2,3-Triazole-containing hybrids as leads in medicinal chemistry: A recent overview

Triazole derivatives and their anti-tubercular activity

Pharmaceutical and medicinal significance of sulfur (SVI)-Containing motifs for drug discovery: A critical review.

Quinoline hybrids and their antiplasmodial and antimalarial activities.

Isatin hybrids and their anti-tuberculosis activity

Recent developments of coumarin-containing derivatives and their anti-tubercular activity

Recent advances of tetrazole derivatives as potential anti-tubercular and anti-malarial agents.

Azide-alkyne cycloaddition towards 1H-1,2,3-triazole-tethered gatifloxacin and isatin conjugates: Design, synthesis and in vitro anti-mycobacterial evaluation.

Zhi Xu

Papers

Quinoline hybrids and their antiplasmodial and antimalarial activities.

Isatin hybrids and their anti-tuberculosis activity

Recent developments of coumarin-containing derivatives and their anti-tubercular activity

Recent advances of tetrazole derivatives as potential anti-tubercular and anti-malarial agents.

Azide-alkyne cycloaddition towards 1H-1,2,3-triazole-tethered gatifloxacin and isatin conjugates: Design, synthesis and in vitro anti-mycobacterial evaluation.