Hydrothermal synthesis of nanostructured Ce-SAPO-34: High-performance and long-lifetime catalyst with various ceria contents for methanol to light olefins conversion

Abstract

The nanostructured SAPO-34 molecular sieve was synthesized via hydrothermal method. In order to enhance SAPO-34 catalytic performance, it was modified with various Ce contents by impregnation method and compared to unmodified catalyst. The synthesized catalysts were characterized by various techniques such as XRD, FESEM, TEM, EDX, BET, FTIR and TPD-NH3. The relative crystallinity, surface area and pore volume of the samples were reduced by Ce addition which was more considerable at higher Ce contents. The strength and concentration of weak and strong acid site were reduced by Ce impregnation. The catalytic performance of the fabricated catalysts was investigated in the methanol to olefins process. Ce incorporation had a strong effect on the lifetime and methane formation. The results confirmed that catalytic performance was improved by using 0.5% CeO2, significantly in viewpoint of increasing lifetime. For the modified catalyst by using 0.5% CeO2, the methanol conversion and olefins selectivity maintained above 90% and 85%, respectively for 720 min of time on stream. High Ce content had negative effect on the textural properties and lifetime of modified catalysts.