Selective conversion of CO2 to isobutane-enriched C4 alkanes over InZrOx-Beta composite catalyst
Han Wang, Sheng Fan, Shujia Guo, Sen Wang, Zhangfeng Qin, Mei Dong, Huaqing Zhu, Weibin Fan, Jianguo Wang
Abstract
Abstract Direct conversion of CO 2 to a single specific hydrocarbon with high selectivity is extremely attractive but very challenging. Herein, by employing an InZrO x -Beta composite catalyst in the CO 2 hydrogenation, a high selectivity of 53.4% to butane is achieved in hydrocarbons (CO free) under 315 °C and 3.0 MPa, at a CO 2 conversion of 20.4%. Various characterizations and DFT calculation reveal that the generation of methanol-related intermediates by CO 2 hydrogenation is closely related to the surface oxygen vacancies of InZrO x , which can be tuned through modulating the preparation methods. In contrast, the three-dimensional 12-ring channels of H-Beta conduces to forming higher methylbenzenes and methylnaphthalenes containing isopropyl side-chain, which favors the transformation of methanol-related intermediates to butane through alkyl side-chain elimination and subsequent methylation and hydrogenation. Moreover, the catalytic stability of InZrO x -Beta in the CO 2 hydrogenation is considerably improved by a surface silica protection strategy which can effectively inhibit the indium migration.