Hollow zeolites have been considered as promising materials due to their unique porosity. Although some progress has been made in the synthesis of hollow zeolites, there are still few reports on the one-step synthesis of high-quality hollow ZSM-5 zeolites. In this work, we used a simple one-step strategy to synthesize high-quality bowl-like hollow ZSM-5 zeolites without additional templates. The strategy involves two key factors including the hydrolysis temperature of TEOS (tetraethoxysilane) and the amount of NaOH. During the preparation of the synthesis gel, the hydrolysis temperature of TEOS was carefully controlled to tune the spatial distribution of Al and Si throughout the micelle/nucleus, creating Al-zoning and a Si-rich core for the formation of intracrystalline macropores. The amount of Na⁺ was adjusted to change the competitive electrostatic interactions with TPA⁺ for negatively charged groups on the surface of crystals, producing bowl-like macropores on the shell of crystals. Various characterizations were made and the formation mechanism of bowl-like hollow ZSM-5 zeolites was proposed.

中文翻译：

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碗状中空 ZSM-5 沸石的一步合成简单易行

空心沸石因其独特的孔隙率而被认为是有前途的材料。尽管在空心沸石的合成方面取得了一些进展，但关于一步合成高质量空心ZSM-5沸石的报道还很少。在这项工作中，我们使用了一种简单的一步策略来合成高质量的碗状空心 ZSM-5 沸石，而无需额外的模板。该策略涉及两个关键因素，包括 TEOS（四乙氧基硅烷）的水解温度和 NaOH 的量。在合成凝胶的制备过程中，仔细控制 TEOS 的水解温度，以调整整个胶束/核中铝和硅的空间分布，从而形成铝区和富硅核，用于形成晶内大孔。Na ⁺的量调整以改变晶体表面带负电荷基团与 TPA ⁺的竞争性静电相互作用，在晶体壳上产生碗状大孔。进行了各种表征，并提出了碗状中空 ZSM-5 沸石的形成机制。