Acta Phys. -Chim. Sin. ›› 2015, Vol. 31 ›› Issue (11): 2139-2150.doi: 10.3866/PKU.WHXB201509281

• CATALYSIS AND SURFACE SCIENCE • Previous Articles     Next Articles

ZSM-5 Zeolite with Micro-Mesoporous Structures Synthesized Using Different Templates for Methanol to Propylene Reaction

Lan-Lan. ZHANG,Yu. SONG,Guo-Dong. LI,Shao-Long. ZHANG,Yun-Shan. SHANG,Yan-Jun. GONG*()   

  • Received:2015-07-06 Published:2015-11-13
  • Contact: Yan-Jun. GONG E-mail:gongyj@cup.edu.cn
  • Supported by:
    the National Key Basic Research Program of China (973)(2012CB215003);National Natural Science Foundationof China(21176255, 21276278)

Abstract:

ZSM-5 zeolites with different pore structures were synthesized using different templates (tetrapropyl ammonium hydroxide (TPAOH), cetyltrimethylammonium bromide (CTAB) and C18-6-6Br2). The obtained nanosized (NZ), mesoporous (MZ), and nanosheets (NSZ) ZSM-5 samples were compared with conventional microporous ZSM-5 zeolite (CZ). The physicochemical properties of these samples were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), N2 adsorption-desorption, and temperature-programmed desorption of ammonia (NH3-TPD). The results showed that the mesopore volumes and surface areas of the four samples increased in the order NSZ > MZ > NZ > CZ, and the ratio of strong/weak acidity increased in the order CZ > MZ > NZ > NSZ. In the methanol to propylene (MTP) reaction, the catalyst porosity played an important role on the product selectivity and catalytic stability. The selectivities for propylene and total olefins improved with increasing mesoporosity; NSZ, with the largest mesopore volume, gave the highest propylene selectivity, i.e., 47.5%, and 78.4% total olefins. Meanwhile, the introduction of mesopores into the ZSM-5 zeolite extended the catalytic lifetime. The NZ sample displayed reliable MTP catalytic activity for 200 h, which was predominately attributed to its optimal combination of acidity and porosity.

Key words: ZSM-5 zeolite, Nanometer, Nanosheet, Mesopore, Methanol to propylene

MSC2000: 

  • O643