2.1. Spray-liquid preparation
We added a typical poly(styrene-co-NIPAAm)/Pd catalyst solution
into ethanol and sonicated the mixture for 10 min to disperse
the Pd catalysts homogeneously. The Pd nanoparticles then
exhibited satisfactory dispersion in the ethanol without any
surfactant.
2.2. Synthesis of carbonaceous samples by using spray pyrolysis
chemical vapor deposition
Fig. 1 shows the schematic of our SPCVD reactor, which comprises
a spray nozzle, a vertical heating furnace, a quartz tube, and a
powder collector. The Pd/C2H5OH-mixed liquid was pumped into
the vertical CVD chamber with compressed argon gas, hydrogen,
and acetylene, to grow carbonaceous products at a temperature of
600e800 C. The synthesis period was 1 h. The synthesized
nanocarbonaceous products on the Pd catalysts were then
observed using scanning electron microscopy (SEM) and transmission
electron microscopy (TEM). Their graphite crystallinitywas
analyzed using Raman spectroscopy.