Probing the dynamics of nanoparticle growth in a flame using synchrotron radiation.

Top of page Flame synthesis is one of the most versatile and promising technologies for large-scale production of nanoscale materials1, 2, 3. Pyrolysis has recently been shown to be a useful route for the production of single-walled nanotubes4, quantum dots5 and a wide variety of nanostructured ceramic oxides for catalysis6 and electrochemical applications7. An understanding of the mechanisms of nanostructural growth in flames has been hampered by a lack of direct observations of particle growth8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, owing to high temperatures (2,000 K), rapid kinetics (submillisecond scale), dilute growth conditions (10-6 volume fraction) and optical emission of synthetic flames. Here we report the first successful in situ study of nanoparticle growth in a flame using synchrotron X-ray scattering. The results indicate that simple growth models, first derived for colloidal synthesis22, can be used to facilitate our understanding of flame synthesis. Further, the results indicate the feasibility of studies of nanometre-scale aerosols of toxicological23 and environmental24 concern.