Hydrogenation of CO2 to light olefins on ZZ/MnSAPO-34@Si-2: Effect of silicalite-2 seeds on the acidity and catalytic activity

• CZZ, ZZ and MnSAPO-34 were coating with Silicalite-2 seed via hydrothermal method. • ZZ/MnSAPO34@Si-2 catalyst exhibited optimal selectivity to light olefins of 70.0%. • CZZ/MnSAPO-34@Si-2 catalyst showed selectivity of 82.1% to light alkane. • The acidity and hydrogenation ability could regulate the product distribution. Light olefin is a primary building block for synthesizing various chemical intermediates and products. CZZ@MnSAPO-34 and ZZ@MnSAPO-34 core–shell catalysts were prepared for hydrogenation of CO 2 via Silicalite-2 seed-assisted in-situ hydrothermal synthesis method. The evaluation results showed that CZZ@MnSAPO-34 favors the generation of light alkanes, while ZZ@MnSAPO-34 benefits the production of light olefins. Further, the core–shell catalysts coating with Silicalite-2 shell denoted as ZZ@Si-2, CZZ@Si-2, and MnSAPO-34@Si-2 were synthesized by the in-situ hydrothermal synthesis technique. The microstructure, acidity, and element distribution of the above core–shell catalysts were investigated by XRD, NH 3 -TPD, and SEM-EDS analysis. The physically mixed ZZ/MnSAPO34@Si-2 exhibited the highest CO-free selectivity for light olefins up to 70.0%, with CO 2 conversion of 17.3% at 380 °C, 2.0 MPa, GHSV = 4800 h −1 . The effective synergistic interactions and weak acidity of the MnSAPO34@Si-2 zeolite favored the formation of light olefins via promoting C C coupling of methanol intermediates and inhibited the secondary hydrogenation. Meanwhile, the strong hydrogenation capacity of the CZZ elevated the selectivity to C 2 0 -C 4 0 (82.1%) on CZZ/MnSAPO-34@Si-2 catalyst. It is found that the modulation of active metal components and inter-component synergy contributes to the regulation of product distribution.