科研之友
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摘要
A novel route for the incorporation of zinc oxide (ZnO) into both the pore channels and surface of the HZSM-5 supports with high homogeneity via atomic layer deposition (ALD) technology is presented. The structural characteristics and methanol-to-aromatics (MTA) performances of synthesized material [ZnO/HZSM-5 (ALD)] were examined against the ZnO/HZSM-5 catalyst prepared by conventional incipient wetness impregnation (IWI) method. After the introduction of ZnO to parent HZSM-5 by IWI, the total BTX aromatics selectivity increased from 29.8 to 34.1 %, whereas the catalyst prepared by ALD with the same loading of Zn species gave a BTX selectivity of 40.1 %. The better BTX activity and selectivity in MTA for ZnO/HZSM-5 (ALD) catalyst could be attributed to the fact that ALD is more favorable for the entrance of Zn species into zeolite crystals. Therefore the synergy effect between the new generated Zn-Lewis sites and Bronsted acid sites inside the zeolite crystals can be effectively enhanced. The deposited ZnO by atomic layer deposition (ALD) was presented in layer-like form, whereas ZnO loaded by incipient wetness impregnation existed as particle morphology. The combined results of N-2 adsorption-desorption, ICP-AES and XPS indicated that ALD was more favorable for the entrance of Zn species into zeolite crystals. As a consequence, the synergy effect between the new generated Zn-Lewis sites and Bronsted acid sites inside the zeolite crystals can be effectively enhanced.
- 出版日期2015-3
- 单位东南大学
