Herein,
we report a general and straightforward synthesis method
for large-pore highly mesoporous metal oxide nanoparticles via a modified
inverse micelle formation. The role of diols as solvents has been
demonstrated and extended to other metal oxides using ethylene glycol.
After scanning most of the metals from the periodic table, magnesium
and calcium from the s-block; tin from the p-block; vanadium, nickel,
zinc, zirconium, and hafnium from the d-block; and lanthanum and cerium
from the f-block elements, all these have been successfully synthesized
as large-pore-diameter metal oxides. Because of thermodynamic stability
of chelate formation, ethylene glycol, 1,3-propanediol, 1,4-butanediol,
and 1,5-pentanediol give a higher pore diameter, whereas a further
increase in the diol carbon chain (1,6-hexanediol and 1,12-dodecandiol)
leads to pore contraction. By varying the synthesis temperature, the
effect of viscosity on the pore diameter has also been demonstrated.
Potential applications of oxides of magnesium have been tested for
carbon dioxide capture and adsorption of macromolecules such as proteins
and lipids and small molecules such as curcumin, dopamine, and sucrose.
As predicted, larger-pore-diameter and higher-pore-volume mesoporous
magnesium oxide shows higher carbon dioxide capture and adsorption
compared to commercial magnesium oxide. A mechanism for the higher
pore diameters of mesoporous metal oxide nanomaterials has been proposed
based on the results and previous reported literature studies.