Flame Synthesis of Nanoparticles

Abstract

An overview of recent advances in the synthesis of nanoparticles by flame aerosol processes is given. In flame processes with gaseous precursors emphasis is placed on reactant mixing and composition, additives, and external electric fields for control of product characteristics. Thermophoretic sampling can monitor the formation and growth of nanoparticles, while the corresponding temperature history can be obtained by non-intrusive Fourier transform infrared spectroscopy. Furthermore, synthesis of composite nanoparticles for various applications is addressed such as in reinforcement or catalysis as well as for scale-up from 1 to 700 g/h of silica-carbon nanostructured particles. In flame processes with liquid precursors using the so-called flame spray pyrolysis (FSP), emphasis is placed on reactant and fuel composition. The FSP processes are quite attractive as they can employ a wide array of precursors, so a broad spectrum of new nanosized powders can be synthesized. Computational fluid dynamics (CFD) in combination with gas-phase particle formation models offer unique possibilities for improvement and possible new designs for flame reactors.

Unconventional ratiometric-enhanced optical sensing of oxygen by mixed-phase TiO2

“…synthesis routes, such as flame processes 31 or sol-gel synthesis 32 . Secondly, we point out that employing a dual-luminescent probe obtained through mixing two polymorph of a same material allows exploiting the ratiometric approach plus the responsivity enhancement without having to tackle possible issues (e.g.…”

Distinguishing between aggregates and agglomerates of flame-made TiO2 by high-pressure dispersion

“…Non-agglomerated TiO 2 particles are desired for pigments or composites [1] while agglomerated ones are desired when making catalyst pellets to facilitate reactant/product flow [2]. The interparticle bond energies can range from weak van der Waals forces (soft agglomerates or just agglomerates) to stronger solidstate necks (hard agglomerates or aggregates) [3].…”

Simultaneous deposition of Au nanoparticles during flame synthesis of TiO2 and SiO2

“…9 Besides the possibility of generating the metal and the ceramic support at the same time, flame technology, and especially the spray flame processes, can provide virtually all kinds of support materials: metal oxides (e.g., alumina, silica, and titania, 5,10 without deposition of metals), mixed metal oxides (e.g., spinel, mullite, and strontium aluminosilicate 11 ) or metal oxide composites (e.g., silica/titania 12 ). For this paper, one-step synthesis of Au/TiO 2 or Au/SiO 2 particles by flame spray pyrolysis was investigated.…”