Carbon‐Based Electron Buffer Layer on ZnOx−Fe5C2−Fe3O4 Boosts Ethanol Synthesis from CO2 Hydrogenation

The conversion of CO2 into ethanol with renewable H2 has attracted tremendous attention due to its integrated functions of carbon elimination and chemical synthesis, but remains challenging. The electronic properties of a catalyst are essential to determine the adsorption strength and configuration of the key intermediates, therefore altering the reaction network for targeted synthesis. Herein, we describe a catalytic system in which a carbon buffer layer is employed to tailor the electronic properties of the ternary ZnOx−Fe5C2−Fe3O4, in which the electron‐transfer pathway (ZnOx→Fe species or carbon layer) ensures the appropriate adsorption strength of −CO* on the catalytic interface, facilitating C−C coupling between −CHx* and −CO* for ethanol synthesis. Benefiting from this unique electron‐transfer buffering effect, an extremely high ethanol yield of 366.6 gEtOH kgcat−1 h−1 (with CO of 10 vol % co‐feeding) is achieved from CO2 hydrogenation. This work provides a powerful electronic modulation strategy for catalyst design in terms of highly oriented synthesis. A carbon‐based electron buffer layer was employed to neutralize the excessive electrons transferred from ZnOx to Fe species. A suitable CO adsorption strength and C−C coupling barrier was achieved as a consequence of the Fe‐based active sites, yielding a high ethanol yield of 366.6 gEtOH kgcat−1 h−1 from CO2+H2. The result differs from the common ZnFe bimetallic catalyst for which hydrocarbons dominate.