pore size did not change much compared to the 0.20 M KNO3 treated sample, it led to the formation of much thicker wall
(Figure 4D). These results confirm the above hypothesis that
one may tailor the pretreatment and pyrolysis condition to
synthesize meso/macroporous silica from RHs with tunable
structures. It should be noted that such secondary porous silica
is semicrystalline