A facile one-pot method without organic templates and seeds is reported for the fabrication of frameworksubstituted heteroatomic zeolites for the first time. Such a breakthrough is achieved by the acidic cohydrolysis of tetraethylorthosilicate (TEOS) with metal salts, followed by basic aging and hydrothermal crystallization. Fe(Mo, Ti, Co, Cr) MFI zeolites can be obtained with high crystallinity, thermal stability and tunable chemical composition, in which Fe 3+ and Al 3+ are proposed to act as co-structure-directing agents, inducing the growth of the zeolite crystal and their special poly-nanocrystalline morphology.Structural characterizations and Knoevenagel condensations were conducted to evidence the incorporation of Fe 3+ into the MFI framework. The catalytic activity on the as-synthesized frameworksubstituted Fe-ZSM-5 is not only tens of times higher than that of Fe 3+ -exchanged or ferric oxide impregnated analogues, but also much higher than that of its as-calcined analogue, suggesting the unique ability of our method to inhibit the transfer of heteroatoms out of the framework. This easy, controllable and green new strategy may be extended to other heteroatomic MFI zeolites, and is potentially important for practical utilization.Scheme 1 Schematic drawing of the procedure for the unseeded all-inorganic hydrothermal synthesis of heteroatomic zeolite Fe-ZSM-5.

Fabricating stable strong basic sites in well-preserved crystallized zeolitic frameworks still remains a difficult issue. Here, we reported a family of MFI-type metallosilicate zeolites, AeS-1 (Ae: alkaline-earth metal ions of Mg, Ca, Sr or Ba; S-1: silicalite-1) through a direct one-pot hydrothermal method involving the acidic co-hydrolysis/condensation of the silica precursor with the Ae salts. Step-by-step full characterizations were designed and conducted for in-depth discussion of the Ae status in AeS-1. Strong basicity (H_≈22.5-26.5) was detected in AeS-1. The basicity was further confirmed by CO2 sorption measurements, (13) C NMR spectra of chloroform-adsorbed samples, and (1) H→(13) C and (1) H→(29) Si cross-polarization magic-angle spinning NMR spectra of ethyl cyanoacetate-adsorbed samples. The results of Knoevenagel condensations demonstrated the excellent solid base catalysis of AeS-1, which showed high activity, reusability, and shape-selectivity, all of which are explained by Ae-derived zeolitic intracrystalline strong basic sites.

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