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 μm, 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.
The statues of active sites such as number and dispersion on the surface of support are essential to improve the catalytic activity. In this paper, highly-dispersed and controllable quantities of vanadia species within channel of mesoporous MCM-41 were directly prepared by a direct templating assembly method (S + L -M + I -). This method was based on the self-assembly of cationic surfactants (CTA + , S + ), chelating agents (citrate ions, L -), vanadyl ions (VO 2+ , M + ) and silicates oligomers (I -) by the electrostatic and chelating interaction. First, the citrate ions were absorbed on the CTA + micelles' surface by electrostatic interaction, the vanadyl ions subsequently were anchored on their surface by chelating with citrate ions to form metallomicelles. Finally, the silicates were deposited on the metallomicelles to obtain the targeted product. The structure of samples, especially the oxidation state and surface distribution of vanadium species on the mesoporous silica were efficiently characterized with different techniques including XRD, N 2 adsorption, SEM, TEM, UV-vis, XPS, FT-IR, ICP and H 2 -TPR.Furthermore, the obtained samples, using hydroxylation of benzene as a probe reaction, exhibited superior catalytic activities when compared with post-synthesized sample.
Three‐dimensionally controllable multichannel silica nanotubes (MC‐SNTs) have been constructed. Quaternary ammonium type (CnH2n+1(CH3)3N+) surfactants were used as structure‐directing agents (SDAs) in basic ammonia. A low concentration of block copolymer HO(CH2CH2O)20[CH2CH(CH3)O]70(CH2CH2O)20H (P123) was employed as an additive. The length, diameter, and pore size of MC‐SNTs can be finely controlled in the range of 50 nm to 5 μm, 50 nm to 350 nm, and 2 nm to 3 nm by changing the molar ratio of P123 and SDA, the concentration of ammonia, and the length of carbon chain of SDAs, respectively. Observations based on transmission electron microscopy confirmed the role of P123 and ammonia in the self‐assembly of micelles of SDA. Compared with the one‐pot method reported previously, the aspect ratios (ARs; length/diameter) of obtained MC‐SNTs were tunable in a wide range of approximately 1 to 100. The tunable MC‐SNTs were used as dual drug‐delivery carriers for anticancer drug doxorubicin (Dox) and anti‐inflammatory drug ibuprofen (Ibu). Results of release behavior and toxicity to cancer cells of Dox–Ibu‐loaded MC‐SNTs with different ARs revealed that Dox and Ibu were successfully codelivered and did not interfere with each other. The produced MC‐SNTs with larger AR values of showed advantages in the amount of accumulated dual drugs, the duration time of release, and inhibition of the growth of HeLa cells.
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