The porous and shriveled morphology of silica particles were thinly or abundantly covered by the silica sol and as
a result RB-like morphology was formed on the surface of silica particles. Fig. S2 (see
Supplementary information) shows the different morphologies of silica particles covered with thin
or thick layer of silica sol. Specifically; thinly covered sol on the silica particles shows RB-like
morphology.