The N2 adsorption–desorption isotherm of RH-silica is
shown in Fig. 4. The sample exhibits a type IV isotherm
and H1 hysteresis loop according to IUPAC classification
[19]. H1 hysteresis loop is a characteristic of mesoporous
material consisting of agglomerates or spherical particles
having a fairly uniform pore size [20]. This is in accordance
with TEM results (evidenced later). The specific
surface area of the sample was found to be 245 m2g -1 and
the pore volume was 0.78 cc g -1. The mesoporous silica