Breaking the activity-selectivity trade-off of CO hydrogenation to light olefins.

Catalytic hydrogenation of CO to value-added fuels and chemicals is of great importance to carbon neutrality but suffers from an activity-selectivity trade-off, leading to limited catalytic performance. Herein, the ZnFeAlO + SAPO-34 composite catalyst was designed, which can simultaneously achieve a CO conversion of 42%, a CO selectivity of 50%, and a C-C selectivity of 83%, resulting in a C-C yield of almost 18%. This superior catalytic performance was found to be from the presence of unconventional electron-deficient tetrahedral Fe sites and electron-enriched octahedral Zn sites in the ZnFeAlO spinel, which were active for the CO deoxygenation to CO via the reverse water gas shift reaction, and CO hydrogenation to CHOH, respectively, leading to a route for CO hydrogenation to C-C, where the kinetics of CO activation can be improved, the mass transfer of CO hydrogenation can be minimized, and the C-C selectivity can be enhanced via modifying the acid density of SAPO-34. Moreover, the spinel structure of ZnFeAlO possessed a strong ability to stabilize the active Fe and Zn sites even at elevated temperatures, resulting in long-term stability of over 450 h for this process, exhibiting great potential for large-scale applications.