Hydrogenation of CO ₂ to Propylene and Butene Over ZnZrO _x /SAPO‐18

Abstract

Abstract Recycling CO 2 to light olefins (C 2 ‐ C 4 ) is a promising strategy for long‐term carbon storage. However, selective hydrogenation to light olefins while suppressing alkane formation remains a challenge. This work presents an optimized ZnZrO x /SAPO‐18 tandem catalyst, which achieves 88.7% light olefins selectivity at 9.5% CO 2 conversion with C 3 +C 4 dominating 68.4% of the hydrocarbons. The catalyst exhibits resistance to over hydrogenation, yielding the (C 2 −C 4 )/(C 2 0 −C 4 0 ) (O/P) ratio of 17.7 and only  1.4% CH 4 selectivity. Furthermore, the catalyst shows good stability over 100 h on stream without obvious deactivation, owing to the synergistic effect between ZnZrO x and the reaction conditions, which facilitates the elimination of coke deposition. Hydrothermal treatment brings more Zn─O─Zr active sites and oxygen vacancies (O v ) on ZnZrO x , as well as the modulated Brønsted acid sites (BAS) in SAPO‐18 suppresses the over‐hydrogenation of olefins, and the AEI‐type cage can contain expanded hydrocarbon pool (HCP) intermediates for enhanced C 3 +C 4 formation. This study advances the development of selective CO 2 ‐to‐olefin conversion technologies.