One-Pot Synthesis of Iron-Containing Nanoreactors with Controllable Catalytic Activity Based on Multichannel Mesoporous Silica

We have constructed Fe-substituted silicate nanotube reactors (Fe-NTRs) through a newly developed one-step solubilization (OSS) method in which cetyltrimethylammonium bromide and P123 are used as structure-directing and shape-controlling agents, respectively, and ferrocene is utilized as iron source by solubilizing inside the hydrophobic inner core of the surfactant micelles. The Fe-NTRs showed regular morphology, highly ordered multichannel mesopores, controllable sizes with lengths changing from 150 nm to 1.2 mm, diameters of approximately 130 nm and pore sizes of approximately 2.7 nm, and iron contents in a range from 0.66 to 1.59 wt%. The OSS strategy is also applicable for other metal-functioned silicate nanoreactors. The catalytic activity of Fe-NTRs in the direct hydroxylation of phenol can be essentially manipulated by the controllable sizes. The release behavior of reactants reveals that the diffusion control derived from the lengths of Fe-NTR should be responsible for the resultant reactivity.