Mesoporous Beta Zeolite-Supported Ruthenium Nanoparticles for Selective Conversion of Synthesis Gas to C5-C11 Isoparaffins
Mesoporous Beta Zeolite-Supported Ruthenium Nanoparticles for Selective Conversion of Synthesis Gas to C5-C11 Isoparaffins
复制标题
介孔β沸石负载钌纳米颗粒用于合成气选择性转化为C5-C11异构烷烃
DOI：
10.1021/cs200670j
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发表时间：
2012-03-01
期刊：
影响因子：
12.9
通讯作者：
Wang, Ye
中科院分区：
文献类型：
--
作者：
Cheng, Kang;Kang, Jincan;Wang, Ye
用NaOH水溶液对H-β进行后处理，制备了介孔β分子筛，并将其作为Ru催化剂的载体，用于F-T合成。随着NaOH浓度的增加，介孔的大小和体积增大。Bronsted酸度下降的原因是后处理过程中Na+离子被交换成Meso-β，再与NH4+进行离子交换，然后焙烧形成H-Meso-Beta，可以恢复Bronsted酸度。用H-Meso-beta或Meso-beta代替H-beta或Na-beta作为FT合成的载体，降低了对CH4和重烃(C-12(+))的选择性，而提高了对C-5-C-11烃的选择性。C-5-C-11的选择性取决于用于制备Meso-β的NaOH的浓度。在最佳NaOH浓度下，当异构烷烃与正构烷烃之比为2.7时，C-5-C-11的选择性为77%，明显高于Anderson-Schulz-Flory分布的最大值(接近45%)。介孔和独特的酸性可能有助于在Ru纳米颗粒上形成的初级重烃选择性加氢裂解成汽油范围的液体燃料。
Mesoporous beta (meso-beta) zeolites prepared by post-treatment of H-beta with NaOH aqueous solution were studied as supports of Ru catalysts for Fischer-Tropsch (FT) synthesis. The size and volume of the mesopores increased with the concentration of NaOH. The Bronsted acidity declined because Na+ ions were exchanged into the meso-beta during the post-treatment, and a further ion exchange of the meso-beta with NH4+ followed by calcination, forming H-meso-beta, could recover the Bronsted acidity. The use of H-meso-beta or meso-beta instead of H-beta or Na-beta as the support for FT synthesis decreased the selectivities to CH4 and heavier hydrocarbons (C-12(+)) and increased that to C-5-C-11 hydrocarbons. The C-5-C-11, selectivity depended on the concentration of NaOH used for meso-beta preparation. Under an optimum NaOH concentration, a C-5-C-11 selectivity of 77%, significantly higher than the maximum expected from Anderson-Schulz-Flory distribution (similar to 45%), was attained with a ratio of isoparaffins to n-paraffins being 2.7. The mesoporosity and the unique acidity of the meso-beta probably contribute to the selective hydrocracking of the primary heavier hydrocarbons formed on Ru nanopartides into gasoline-range liquid fuels.