Effect of zeolite topology on the hydrocarbon distribution over bifunctional ZnAlO/SAPO catalysts in syngas conversion

Abstract

Recent studies demonstrate that bifunctional catalysts composed of metal oxide and zeolite can effectively control the hydrocarbon distribution in syngas conversion. In this effort, a set of eight silicoaluminophosphate (SAPO) zeolites with different topology structures are synthesized and integrated with a binary ZnAlO oxide for syngas conversion. The effects of micropore window size and cage size of SAPO zeolites, and reaction conditions on the hydrocarbon distribution are preliminarily investigated. It was found that the hydrocarbon distribution is primarily determined by the window size of SAPO zeolites, and a volcano trend was observed between the chain length of hydrocarbon products and the window sizes. The cage size of zeolites and reaction conditions only modifies the hydrocarbon distribution in a narrow range of chain length. The effect of zeolite topology on the hydrocarbon distribution in syngas conversion is overall in line with that in methanol conversion. These findings provide an efficient strategy to increase the selectivity of an individual hydrocarbon product in syngas conversion, such as ethylene, propylene, butenes, iso-butane and C5–C11iso-paraffins.