Efficient Fe‐Based Catalysts Prepared by Atomic Layer Deposition for CO2 Hydrogenation to Higher Hydrocarbons

In this work, atomic layer deposition (ALD) of Fe is applied for the first time to prepare YZrOx‐supported catalysts for CO2 Fischer–Tropsch synthesis (CO2‐FTS). The ALD catalysts promoted via physical mixing with K2CO3 clearly outperformed a catalyst of the same K‐Fe loading but prepared via incipient wetness impregnation (IWI) by achieving higher CO2 conversion and lower CH4 selectivity. The best K‐promoted ALD catalyst achieved similar C2+‐hydrocarbon and C2‐C4 olefin yield and suppression of CH4 formation as state‐of‐the‐art bulk Fe‐based catalysts, despite its significantly lower Fe content. Spatially resolved characterization of spent catalysts revealed that the superior performance of the K‐promoted ALD catalysts is linked to a higher Fe5C2 content and an improved spatial distribution of Fe5C2 along the catalyst bed. The enhanced formation/stabilization and distribution of Fe5C2 in the ALD catalysts may be related to differences in Fe species morphology, which may interact more significantly with K2CO3. Additionally, operando DRIFTS measurements revealed different intermediates on the surface of IWI and ALD catalysts possibly involved in CH4 and higher hydrocarbon formation. We put forward that ALD is an advantageous method for preparing efficient supported Fe‐based catalysts for CO2‐FTS, which offers a new opportunity to explore for selectivity tuning and activity enhancement.