MFI zeolite coating with intrazeolitic aluminum (acidic) gradient supported on SiC foams to improve the methanol-to-propylene (MTP) reaction
MFI zeolite coating with intrazeolitic aluminum (acidic) gradient supported on SiC foams to improve the methanol-to-propylene (MTP) reaction
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DOI：
10.1016/j.apcata.2018.04.006
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发表时间：
2018-06
期刊：
影响因子：
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通讯作者：
Yilai Jiao;Yilai Jiao;Yilai Jiao;Shaojun Xu;Chunhai Jiang;Michal Perdjon;Xiaolei Fan;Jinsong Zhang-Jinsong
中科院分区：
文献类型：
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作者：
Yilai Jiao;Yilai Jiao;Yilai Jiao;Shaojun Xu;Chunhai Jiang;Michal Perdjon;Xiaolei Fan;Jinsong Zhang-Jinsong
为了抑制甲醇制丙烯反应的失活，提高丙烯的选择性，提出了在SiC泡沫载体（G-MFI/SiC泡沫）上负载沸石内铝（酸性）梯度的MFI涂层。采用固体多晶硅合成G-MFI/SiC泡沫催化剂，延长了二氧化硅营养物在液相中的释放时间，抑制了沉淀现象。所得MFI涂层沿SiC泡沫表面法向呈现铝梯度，ZSM-5层（约20 μm）靠近SiC表面，其次是硅石-1层（约10 μm）。MFI涂层中的氧化铝（酸性）梯度使其形成一个被动的硅石-1外层，具有相当多的弱酸性和中酸性位点，阻止了焦炭的形成，并促进了MTP反应对丙烯的选择性。与传统的ZSM-5/SiC泡沫催化剂相比，G-MFI/SiC泡沫催化剂在MTP反应中表现出优异的性能，具有良好的催化寿命（8 hvs）。76 h为>95%甲醇转化率)和低焦炭沉积(6.7 × 10−3wt。% h−1 vs.0.26 wt。% h−1)，以及高丙烯选择性（约36%对46%）。
To hinder the deactivation and improve the propylene selectivity in the methanol-to-propylene (MTP) reaction, MFI coating with the intrazeolitic aluminum (acidic) gradient supported on SiC foam support (G-MFI/SiC foam) was proposed. The solid polycrystalline silicon was used in the synthesis of G-MFI/SiC foam catalyst provided a prolonged release of silica nutrient in the liquid phase and suppressed the precipitation phenomena. The resulting MFI coating showed the aluminum gradient along the surface normal direction of SiC foams with ZSM-5 layer (about 20 μm) near the SiC surface followed by the silicalite-1 layer (about 10 μm). The alumina (acidic) gradient in the MFI coating renders a passive outer layer of silicalite-1 with fairly large amount of weak and medium acid sites prevented the coke formation as well as promoted the selectivity to propylene in the MTP reaction. Compared to the conventional ZSM-5/SiC foam catalyst, the G-MFI/SiC foam catalyst showed excellent performance in the MTP reaction with good catalytic longevity (8 hvs.76 h for >95% methanol conversion) and low coke deposition (6.7 × 10−3wt.% h−1vs.0.26 wt.% h−1), as well as high propylene selectivity (ca.36%vs.46%).