Encapsulated Ni Nanoparticles within Silicalite-1 Crystals for Upgrading Phenolic Compounds to Arenes
Encapsulated Ni Nanoparticles within Silicalite-1 Crystals for Upgrading Phenolic Compounds to Arenes
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DOI：
10.1021/acs.iecr.1c01856
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发表时间：
2021-09
影响因子：
4.2
通讯作者：
Jimei Zhang;Feng Duan;Yongbing Xie;Pengge Ning;He Zhao;Yanchun Shi
中科院分区：
文献类型：
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作者：
Jimei Zhang;Feng Duan;Yongbing Xie;Pengge Ning;He Zhao;Yanchun Shi
通过调整水热合成条件和原料配比，在不同晶粒度的Silicalite-1基质中成功包覆了约3-5 nm的Ni纳米粒子，并将其应用于酚类化合物氢解为芳烃的反应中。Ni含量和纳米颗粒相近的Ni@Silicalite-1晶体尺寸越小，表征的活性中心越明显。随着Ni@Silicalite-1晶粒度的减小，苯酚/间甲酚的转化率和苯/甲苯的选择性都得到了提高，这主要是由于羟基的选择性消除、芳烃的进一步加氢受阻和甲烷的生成。此外，首次报道了Ni@Silicalite-1分子筛在间甲酚转化过程中的高稳定性，其转化率从8h的78.4%提高到334h的76.2%，芳烃产率从8h的73.1%提高到334h的72.6%，从而提供了一种终端优先的方法，通过热力学有利的平坦模式实现不同于苯环加氢反应的选择性控制。负载于沸石中的镍纳米粒子提供了一种新的方法来调节反应物的吸附方式，以修饰由于Silicalite-1基质的形状选择性而产生的芳香族选择性空间效应，这也有助于提高镍纳米粒子的稳定性。
About 3–5 nm Ni nanoparticles were significantly encapsulated within different crystal sizes of a silicalite-1 matrix through tailoring the hydrothermal synthesis conditions and ratios of feeding materials, which were applied in the upgrading of phenolic compounds to arenes via the hydrogenolysis route. The smaller the sizes of Ni@silicalite-1 crystals with similar Ni contents and nanoparticles, the more obvious the active centers could be characterized. The enhancement in both phenol/m-cresol conversion and benzene/toluene selectivity was obtained with the decrease in crystal sizes of Ni@silicalite-1, which originated from the selective elimination of the hydroxyl group, hindrance of further hydrogenation of aromatics, and the formation of methane. Furthermore, Ni@silicalite-1 was first reported for its superior stability for more than 300 h duringm-cresol conversion, which maintained a high conversion from 78.4% at 8 h to 76.2% at 334 h and aromatics yield from 73.1% at 8 h to 72.6% at 334 h. Therefore, Ni@silicalite-1 provided an alternative methodology for terminal priority to achieve selectivity control different from hydrogenation on phenyl rings via a thermodynamically favorable flat mode. Ni nanoparticles encapsulated within zeolites provided a new method to regulate the adsorption mode of reactants to modify aromatic selectivity steric effects originating from shape selectivity of the silicalite-1 matrix, which also contributed to much better stability of Ni nanoparticles.