Selective Transformation of CO 2 and H 2 into Lower Olefins over In 2 O 3 ‐ZnZrO x /SAPO‐34 Bifunctional Catalysts

Because lower olefins (C 2 = –C 4 = ) are important bulk petrochemicals, their direct production from CO 2 hydrogenation is highly attractive. However, the selectivity towards C 2 = –C 4 = by the modified Fischer–Tropsch synthesis is restricted to 56.7 % with high undesired methane selectivity. Here, a series of bifunctional catalysts containing In 2 O 3 ‐ZnZrO x oxides and various SAPO‐34 zeolites with different crystal sizes (0.4–1.5 μm) and pore structures was developed for the production of lower olefins by CO 2 hydrogenation. The C 2 = –C 4 = selectivity reached as high as 85 % among all hydrocarbons with very low CH 4 selectivity of only 1 % at a CO 2 conversion of 17 %. This demonstrated that the small crystal size, hierarchical pore structure, and appropriate amount of Brønsted acid sites of SAPO‐34 endowed the bifunctional catalysts with high C 2 = –C 4 = selectivity. This work shows an efficient way for developing bifunctional catalysts for direct CO 2 hydrogenation to lower olefins.