Soot inception: Carbonaceous nanoparticle formation in flames

The route by which gas-phase molecules in hydrocarbon flames form condensed-phase carbonaceous nanoparticles (incipient soot) is reviewed. These products of incomplete combustion are introduced as particulates and materials revealing both their useful applications and unwanted impacts as pollutants. Significant advances in experimental techniques in the last decade have allowed the gas phase precursors and the transformation from molecules to nanoparticles to be directly observed. These measurements combined with computational techniques allow for various mechanisms known to date to be compared and explored. Questions remain surrounding the various mechanisms that lead to nanoparticle formation. Mechanisms combining physical and chemical routes, so-called physically stabilised soot inception, are highlighted as a possible middle way.

Automated summary

This review discusses the formation of carbonaceous nanoparticles from gas-phase molecules in hydrocarbon flames, highlighting both their useful applications and negative impacts as pollutants. Advances in experimental techniques have allowed for the direct observation of gas phase precursors and the transformation into nanoparticles over the past decade. Questions remain regarding the mechanisms leading to nanoparticle formation, with physically stabilised soot inception proposed as a potential middle ground combining physical and chemical routes.