HZSM-5 is a widely used catalyst for the conversion of methanol to aromatics (MTA), but its single micropore system often results in severe diffusion limitations, leading to the decrease of reaction rate and the change of selectivity to aromatics, as well as affecting the carbon deposition and catalyst deactivation. Thus, an ingenious protective desiliconization method with a mixed solution of sodium hydroxide and tetrapropylammonium hydroxide as a desiliconization agent was developed to create hierarchical porous systems without destruction of the main structure of the molecular sieve. Such modification leads to the greatly increased mesoporous volume from 0.12 to 0.38 cm³ g⁻¹, and only slightly decreased microporous volume from 0.12 to 0.09 cm³ g⁻¹. However, the desiliconization sharply increases the acidity of the catalyst (from 0.248 to 0.341 mmol g⁻¹ for the strong acid sites), which may significantly affect the distribution of aromatics and accelerate the carbon deposition rate. Thus, the deposition of inert SiO₂ on the catalyst surface is subsequently carried out to passivate the surface acidity and adjust the orifice of the catalyst. Accordingly, a hierarchical porous HZSM-5 molecular sieve catalyst (Si@Z5-Na + TP) with suitable acidity is precisely prepared, which exhibits the high selectivity to benzene, toluene and xylenes (BTX) with the excellent anticoking ability in the MTA reaction. The selectivity to BTX in aromatics (63.32%) and the carbon deposition rate (0.91 mg g_cat⁻¹ h⁻¹) over the Si@Z5-Na + TP catalyst are both much more superior than those over the parent HZSM-5 catalyst (47.5% and 2.23 mg g_cat⁻¹ h⁻¹, respectively).

HZSM-5是广泛用于甲醇转化为芳烃（MTA）的催化剂，但其单一的微孔系统通常会导致严重的扩散限制，从而导致反应速率降低和对芳烃的选择性变化，并影响碳沉积和催化剂失活。因此，开发了一种巧妙的保护性脱硅方法，该方法使用氢氧化钠和氢氧化四丙铵的混合溶液作为脱硅剂，以创建分层的多孔系统，而不会破坏分子筛的主要结构。这种修饰导致介孔体积从0.12 cm ³ g ^-1大大增加，而微孔体积从0.12 cm ³ g稍微减小到0.09 cm ³ g ^-1-1。但是，脱硅作用急剧增加了催化剂的酸度（对于强酸位，从0.248增加到0.341 mmol g ^-1），这可能会显着影响芳烃的分布并加快碳沉积速率。因此，随后进行惰性SiO ₂在催化剂表面上的沉积以钝化表面酸度并调节催化剂的孔口。因此，可以精确地制备出具有适当酸度的分级多孔HZSM-5分子筛催化剂（Si @ Z5-Na + TP），该催化剂对苯，甲苯和二甲苯（BTX）的选择性高，在MTA反应中具有出色的抗结焦能力。 。芳香族化合物对BTX的选择性（63.32％）和碳沉积速率（0.91 mg g _cat ^-1相比Si @ Z5-Na + TP催化剂，h ^-1）都优于母体HZSM-5催化剂（分别为47.5％和2.23 mg g _cat ^-1 h ^-1）。