Incorporation of mono and bimetallic MnNi into SAPO‐34 framework used in conversion of methanol to ethylene and propylene: Alteration of acidic properties and catalytic performance

Abstract

Nanostructured Ni, and MnNi) catalysts were synthesized by hydrothermal method using diethylamine (DEA) as template. The influence of Ni, Mn, and MnNi metal ions incorporation into the SAPO-34 framework was investigated on its physicochemical properties and catalytic performance towards methanol to light olefins. The samples were characterized by X-ray diffraction, field emission scanning electron microscopy, particle size distribution, energy dispersive X-ray, Brunner-Emmett-Teller, Fourier transform infrared, UV-vis spectroscopy, and temperature-programmed desorption of ammonia techniques. The results of X-ray diffraction patterns revealed that various metals, based on their unique characteristics, play different roles in the crystallization of SAPO-34 crystalline phase. The energy dispersive X-ray micrographs indicated appropriate distribution of Mn metal ions in comparison with Ni modifier. The catalytic performance of these catalysts showed that the type of metal ions has low effect on methanol conversion, whereas it has considerable effect on stability and products selectivity. The stability of MnAPSO-34 catalyst is much higher than the others. The selectivity of olefins for this sample with a high specific surface area and proper distribution of strong/weak acid sites was about 98% after 10 hr. The main steps of metal ions incorporation into the SAPO-34 framework and a possible reaction mechanism for methanol to light olefins process were discussed in details.

Altering C2H4/C3H6 yield in methanol to light olefins over HZSM-5, SAPO-34 and SAPO-34/HZSM-5 nanostructured catalysts: influence of Si/Al ratio and composite formation

“…[21][22][23] It has been well established that the small pore silicoaluminophosphate, SAPO-34, is an extremely efficient shape selective catalyst for the MTO process, which has high stability and ethylene yield. [24][25][26] However, it is rapidly deactivated by coke formation. [27][28][29][30] On the other hand, HZSM-5 zeolite has high propylene yield and long catalyst lifetime, but the selectivity toward total olens is low.…”

Composite Nanostructure of Manganese Cluster and CHA-Type Silicoaluminaphosphates: Enhanced Catalytic Performance in Dimethylether to Light Olefins Conversion

“…In the previous literatures, the incorporation of heteroatoms into the zeolite’s framework can promote the product distribution in the methanol to hydrocarbon process, which could be attributed to the modifications of the acidic strength, the acid distribution, the pore size, and the channel length of zeolite by the incorporated heteroatoms [ 9 , 10 , 11 , 12 , 13 ]. Liu and Su et al directly incorporated a serial of metal ions into the SAPO-34 molecular sieve using the metal salts, which slightly improved the selectivity for ethylene and propylene [ 9 ].…”