Enhanced gas‐phase nucleation of diamond nanoparticles in a microplasma torch

In this work, we present and characterize a microwave plasma microtorch that can support the formation of diamond nanoparticles (DNPs) in the gas phase when using hydrogen‐methane as a precursor gas. We first showed how the nonequilibrium character of the plasma obtained in this microtorch ensures enhanced H‐atom, C 2 ${{\rm{C}}}_{2}$, and CH 3 ${\text{CH}}_{3}$ production at moderate gas temperature levels that provides thermal stability of DNPs. The material characterization by TEM, Raman, and electron energy loss spectroscopy spectra confirm the presence of a substantial amount of diamond phase in the carbon dust particles collected from the plasma phase. Investigation of the effects of injected microwave power on the process characteristics showed a direct correlation between enhanced C 2 ${{\rm{C}}}_{2}$ production and the appearance of the diamond phase, which points out the critical role of C 2 ${{\rm{C}}}_{2}$ as far as gas‐phase nucleation of DNPs is concerned. Production of diamond nanoparticles using a microplasma torch through homogeneous nucleation under enhanced concentrations of H‐atom and primary carbon radicals C 2 ${{\rm{C}}}_{2}$ and CH 3 ${\text{CH}}_{3}$.