Fabrication of unique hollow silicate nanoparticles with hierarchically micro/mesoporous shell structure by a simple double template approach

An innovative type of hollow silicate nanoparticle with a micro/mesoporous shell wall (NSHPMS) was synthesized at room temperature via an eco-friendly double template approach, followed by simple acid reflux. TEM observations of NSHPMSs showed hollow interior nanoparticles (<100 nm) with a wormhole-like shell structure. The nitrogen gas (N2) adsorption/desorption isotherm exhibited a unique two-step pattern: the first step (0.2 < P/Po < 0.35) signifies the presence of the micro/mesoporous shell wall while the second step (0.85 < P/Po < 0.99) represents the void space in between the NSHPMSs. This resulted to an improved specific surface area up to ∼2055.5 m2 g−1 and a total pore volume as high as ∼6.59 cm3 g−1 which is better compared with the usual reported data for hollow particles with a mesoporous shell wall. The stable wormhole mesoporous shell wall provided sufficient spaces that contribute to high adsorption capacities and faster adsorption rates. One can envision that larger quantities of framework composition can be obtained using our NSHPMSs. (paper)