In this study, ZSM‐5 zeolite with hierarchical porosity structure was synthesized by hydrothermal method using Al(OH)3, SiO2 extracted from coal fly ash as aluminum source and silicon source. The optimal synthesis parameters of ZSM‐5 zeolite were determined via an orthogonal analysis table. The optimum synthesis conditions were: SiO2/Al2O3/Na2O/hexadecyltrimethylammonium bromide/tetrapropyl ammonium bromide/H2O = 1/0.08/0.25/0.05/0.17/50, and the optimum crystallization temperature and crystallization time were 160 °C and 48 h, respectively. Scanning electron microscopy showed that the synthesized ZSM‐5 zeolite exhibited a spherical shape. Nitrogen adsorption‐desorption and Brunauer‐Emmett‐Teller measurement analysis displayed that the best sample ZSM‐5 molecular sieve showed a typical type IV isotherm, and the micropores and mesopores coexisted in the sample, indicating the successful preparation of ZSM‐5 zeolite with hierarchical porosity structure. The crystal growth of ZSM‐5 under different hydrothermal conditions follows the “S” adjustment.
SiC@SiO nanowires, as a functional nanocomposite, have attracted widespread attention due to their fascinating performance and broad application prospect. However, the low-cost, high yield preparation of large-scale SiC@SiO nanowires is still a bottleneck, which hinders their industrial application. Herein, a carbothermal reduction strategy has been developed to synthesize SiC@SiO nanowires, which breaks through the handicap of the traditional growth pattern that uses the aid of a substrate. Systematic characterization results illustrate that the yield of the as-obtained products greatly depends on the heating rate, and ten-gram scale SiC@SiO nanowires (∼27.2 g) composed of a cubic β-SiC core and homogeneous amorphous SiO coating are achieved under the optimum process parameters. The in situ mechanisms of expansion-insertion-growth and inhibition of expansion-package-obstruction are proposed to rationally interpret the growth process of SiC@SiO nanowires and the effect of various heating rates, respectively. Furthermore, the SiC@SiO nanowires display violet-blue photoluminescence and electromagnetic wave absorption properties. This study not only provides some beneficial suggestions for the commercial production of SiC@SiO nanowires, but also reveals promising applications of SiC@SiO nanowires in the optical and electromagnetic shielding fields. Moreover, the developed novel in situ growth mechanism enriches the growth theory of one-dimension nanomaterials and offers inspiration for their industrial-scale production.
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