Chromite–Zeolite Catalysts for Syngas Conversion to Hydrocarbons: Insights into Oxide–Zeolite Interactions

Abstract

A key challenge in modern society is developing the sustainable processes for producing vital chemicals, such as hydrocarbons, from renewable raw materials. The OX-ZEO process, which uses bifunctional catalysts to convert syngas into hydrocarbons, offers a potential alternative to the nonsustainable cracking process. Combining oxide materials with zeolites enables the direct synthesis of various hydrocarbon products with high selectivity. However, challenges remain, particularly regarding carbon monoxide (CO) conversion and unwanted carbon dioxide (CO₂) generation. This study explores the impact of bimetallic chromites combined with H-MOR zeolite on the reaction outcome. Comparative experiments using only the oxide versus the bifunctional catalyst revealed a clear link between the methanol synthesis activity of the oxide and the overall activity in the OX-ZEO process. Furthermore, catalytic tests with monometallic oxides paired with H-MOR highlighted the role of the oxide's crystal structure in syngas conversion. These findings offer insights into the oxide–zeolite interactions, enabling the development of improved catalyst combinations that enhance the CO conversion, reduce CO₂ formation, and maintain high product selectivity.