CO ₂ Hydrogenation Over K‐Promoted Fe‐Catalysts Derived from Mg–Al–Fe Quintinite‐Like Layered Double Hydroxide Precursor

Abstract This work investigates the performance of iron‐based catalysts for CO 2 hydrogenation, whereby the iron‐carbide active phase is derived from a high surface area Mg–Al–Fe quintinite‐like layered double hydroxides precursor. CO 2 temperature‐programmed desorption experiments on calcined and carburized materials demonstrate that K addition increases surface basicity, promoting CO 2 adsorption. CO temperature‐programmed reduction and HR‐TEM/EDS experiments reveal that adding K facilitates CO dissociation, altering the surface carbon/hydrogen pool. Both H 2 ‐TPR and reverse water–gas shift tests at 1 atm show that K addition suppresses H‐transfer. The highest yield of CO and the lowest yield of CH 4 from RWGS occur for the carburized catalyst having a K‐promoter. Adding K improves the product distribution for both Fischer–Tropsch synthesis and CO 2 hydrogenation. For FTS, adding K decreases methane selectivity (from 14% to 4.4%) and increases C 5 + selectivity (from 38% to 51.1%). For CO 2 hydrogenation, adding K decreases CH 4 selectivity from 40%–50% to 19.0% and increases C 5 + selectivity from 0–8% to 37.9%, and the catalyst performs significantly better than a typical precipitated Fe FTS catalyst. At a conversion two times higher than a related CuFe 8 ‐LDO catalyst reported recently, the C 5 + selectivity was ∼4 times higher. The C 5 + selectivity results are also comparable to a recently reported ZnAlFe‐LDH catalyst.