High-Temperature Transformation of Fe-Decorated Single -Wall Carbon Nanohorns to Nanooysters : A Combined Experiment

1. CNMS User Highlight High-Temperature Transformation of Fe-Decorated Single-Wall Carbon Nanohornsto Nanooysters: A Combined Experimental and Theoretical Study Scientific Achievement Elucidated a growth mechanism for new hybrid“nanooysters” – encapsulated metal nanoparticles in hollow carbon shells – that were formed by transforming carbon nanocones with metal nanoparticles at elevated temperatures. Significance This work establishes a “nano-enabled materials design” approach, wherein theory, synthesis, and characterization are used to unravel the atomistic mechanisms driving the formation of new type of carbon-metal system. Nanooysters can be readily produced and show promise for new functional properties as encapsulated metallic quantum dots. • Research Details • CNMS and ShaRE Capabilities: • Density functional theory-based calculations simulated the growth mechanisms of new types of functional carbon materials. • Single-wall carbon nanohorns were synthesized by high power laser vaporization, decorated with metal nanoparticles by e-beam evaporation, and rapidly laser-annealed to 1000°C to form the nanooysters. • AR-Z-STEM, bright-field HRTEM, and EELS characterized the nanohorns and nanooysters. The process by which curved nanocones of carbon (blue) encapsulate Fe nanoparticles (red) to form a new hybrid “nanooyster” material (inset) is shown through snapshots of QM/MD simulations. Background is an aberration-corrected, atomic resolution, Z-STEM image of single wall carbon nanohorns and unconverted graphene flakes which served as the feedstock in the process. K. R. S. Chandrakumar, J. D. Readle, C. Rouleau,A. Puretzky, D. B. Geohegan, K. More, V. Krishnan, M. Tian, G. Duscher, B. G. Sumpter,S. Irle, K. Morokuma,Nanoscale.DOI: 10.1039/c0xx00000x.