Direct Conversion of Carbon Dioxide to Light Olefins Over In –Zr– Cr/SAPO -۳۴ Bifunctional Catalyst

The alarming increase in atmospheric CO₂ levels is a key driver of global climate change, emphasizing the urgent need for sustainable carbon recycling technologies. Among them, catalytic hydrogenation of CO₂ into light olefins (C₂ –C₄) using bifunctional oxide–zeolite (OXZEO) catalysts has emerged as a promising approach, especially via a methanol-mediated pathway that offers high olefin selectivity. In this study, ternary metal oxides consisting of indium, zirconium, and chromium were synthesized at molar ratios of ۳:۱:۱, ۳:۱:۲, and ۳:۱:۳ via co-precipitation. Chromium served as a promoter to enhance catalytic efficiency and structural stability. Two incorporation methods—physical mixing and a core–shell strategy—were employed to combine the oxides with SAPO-۳۴ zeolite in a ۱:۱ weight ratio. The CO₂ hydrogenation reaction was conducted under typical conditions (T = ۶۵۳ K, P = ۳ MPa, H₂/CO₂ = ۳:۱), and catalyst characterization was performed using XRD, FTIR, FESEM, and BET analyses. The results showed that the core–shell structure provided better dispersion and stronger metal–zeolite interactions, resulting in higher selectivity to light olefins. The presence of chromium as a promoter notably improved the catalytic performance, making In–Zr–Cr/SAPO-۳۴ a promising catalyst system for CO₂ valorization.

کلیدواژه ها:

Direct hydrogenation of CO₂ ، MTO process ، Light olefins ، metal oxide catalyst