In conclusion, biogenic porous silica nanoparticles with a
diameter of ca. 25−30 nm were successfully prepared from
HCl-treated RH biomass via controlled pyrolysis. The SAXS
and surface area characterizations further showed that the silica
nanoparticles were composed of smaller primary particles, and
the clustering of the primary particles leads to porous structure.
More importantly, by doping the synthesized silica nanoparticles
with K+ cations and tailoring pyrolysis conditions, the
silica nanoparticles can be further converted to semicrystalline
meso/macroporous frameworks with tunable pore size. Their
high surface area, low cost, and appreciable structure integrity
may lead to many new applications in the near future.