Coke formation is a major reason in deactivation of acidic zeolite catalysts in industrial processes such as methanol to hydrocarbons conversion. Protecting the surface of acidic zeolite with an inert porous shell can greatly hinder the coke formation on the surface, and hence boost the lifetime of the catalyst. In this work, a solid-state steam-assisted method for synthesis of such optimized protective shell (silicate-1, ~15 nm thickness) is designed. This general and simple protocol can be applied to acidic zeolite catalysts to improve their catalytic lifetime. The silicalite-1 shell is synthesized on mesoporous ZSM-5 zeolite to explore its catalytic activity in methanol to hydrocarbons conversion. XPS and TEM analysis confirm the coverage of mesoporous zeolite crystals by non-acidic shell. In addition, nitrogen physisorption shows the accessibility of mesoporous ZSM-5 via microporous silicalite-1 network. Applying this protective shell increases the lifetime of the catalyst by 100% and its conversion capacity by 130%, in comparison to mesoporous ZSM-5 without the shell. The controlled formation of thin layer of microporous silicalite-1 around mesoporous ZSM-5 crystals (without growth of individual silicalite-1) accounts for enhanced catalytic improvement.

焦炭的形成是在工业过程中使酸性沸石催化剂失活的主要原因，例如甲醇到碳氢化合物的转化。用惰性多孔壳保护酸性沸石的表面可以极大地阻碍表面上焦炭的形成，从而延长催化剂的寿命。在这项工作中，设计了一种固态蒸汽辅助方法来合成这种优化的保护壳（硅酸盐-1，厚度约为15 nm）。该通用且简单的方案可以应用于酸性沸石催化剂以提高其催化寿命。在介孔ZSM-5沸石上合成了silicalite-1壳，以探索其在甲醇转化为烃类中的催化活性。XPS和TEM分析证实了非酸性壳层对中孔沸石晶体的覆盖。此外，氮的物理吸附表明，介孔ZSM-5通过微孔silicalite-1网络可及。与没有外壳的中孔ZSM-5相比，采用这种保护性外壳可将催化剂的寿命延长100％，并将其转化能力提高130％。在中孔ZSM-5晶体周围（没有单独的silicalite-1的生长）周围微孔silicalite-1薄层的受控形成说明了催化性能的提高。