Ga CrO /H-SAPO-34(F), a highly efficient bifunctional catalyst for the direct conversion of CO2 into ethene and propene

Adding Ga in Ga m CrO x can regulate the adsorption and activation of CO 2 and H 2 , whereas adding HF during synthesis can modulate the acidity of H-SAPO-34 ( n F). The Ga 0.15 CrO x /H-SAPO-34(0.5/1.0 F) composite exhibits excellent performance in the direct hydrogenation of CO 2 to light olefins. • Ga m CrO x /H-SAPO-34(F) shows excellent catalytic performance in CO 2 to light olefins. • Ga 0.15 CrO x has pertinent oxygen vacancies and moderate CO 2 and H 2 adsorption strength. • Adding HF during synthesis can modulate the acid quantity and strength of H-SAPO-34. • Product spectrum of CO 2 hydrogenation can be regulated over Ga m CrO x /H-SAPO-34(F). • Olefins product is concentrated in ethene and in particular propene (C 2 = –C 3 = > 94 %). The conversion of CO 2 into light olefins is considered as an effective route for the sustainable production of valuable chemicals as well as the remission of global warning induced by excessive CO 2 emission; however, it is still rather challenging to get a catalyst with satisfactorily high yield for the target products. Herein, we designed a new bifunctional Ga m CrO x /H-SAPO-34( n F) catalyst, which exhibits excellent performance in the direct hydrogenation of CO 2 to light olefins; the selectivity to ethene, propene and butenes (C 2 = –C 4 = ) reaches 87.3 % (excluding CO) at a CO 2 conversion of 11.9 % and selectivity of 34.5 % to CO, at 350 °C and 3.0 MPa. Various characterization results indicate that the structure and performance of Ga m CrO x oxide moiety is related to the Ga/Cr molar ratio ( m ); Ga 0.15 CrO x is provided with abundant oxygen vacancies and moderate CO 2 and H 2 adsorption strength and can effectively catalyze the hydrogenation of CO 2 to methanol and related intermediates. In addition, adding proper amount of HF during the synthesis of H-SAPO-34( n F) zeotype moiety can modulate the quantity and strength of Brønsted acid sites and then meliorate the C C bond coupling and cracking reactions. As a result, for the CO 2 hydrogenation over the Ga 0.15 CrO x /H-SAPO-34(F) composite catalyst, ethene and propene predominate the light olefins product (accounting for above 94 %), whereas higher olefins are greatly suppressed. Current work supplies a practical measure or helpful hint for the design of efficient catalysts in the selective conversion of CO 2 to target olefins.