Selective CO₂ Hydrogenation to Hydrocarbons on Cu-Promoted Fe-Based Catalysts: Dependence on Cu–Fe Interaction

Abstract

Conversion of CO2 to sustainable chemical feedstocks and fuels by reacting with renewable hydrogen is considered to be a promising direction in energy research. The selectivity of desired products, such as C2–C4 = and C5+, is low over unpromoted iron-based catalysts for CO2 hydrogenation. Therefore, promoters are often used to tailor and optimize the product distribution. In this work, the effect of doping Cu into Fe-based supported catalysts on the catalytic performance for CO2 hydrogenation to hydrocarbons was studied with a particularly focus on the interaction between Fe and Cu. For this purpose, catalysts with different Fe and Cu distribution were prepared by various impregnation methods. It was found that the selectivity of C2–C4 = over Cu-promoted catalysts decreased, but a significant improvement was obtained for C5+. This promoting behavior is different from that of other promoters (e.g., K, Mn, Zn, etc.). The secondary conversion of produced olefins on Cu-promoted catalysts, which results from the improvement of olefins adsorption, on Cu-promoted catalysts leads to the decrease of C2–C4 = (hydrogenation) but the increase of C5+ (oligomerization). Characterization results demonstrate that the catalytic performance is evidently associated with the strength of the interaction between Fe and Cu in the supported catalysts.

CO2 valorisation via reverse water-gas shift reaction using promoted Fe/CeO2-Al2O3 catalysts: Showcasing the potential of advanced catalysts to explore new processes design

“…The addition of Mo shifts the reduction peaks of FeO x to higher temperature, which is consistent with results shown by Liu et al [49], revealing hindered overall reducibility.…”

Novel Heterogeneous Catalysts for CO2 Hydrogenation to Liquid Fuels

“… 96 The introduction of Cu as a promoter facilitates the reduction of ferric oxide and enhances CO 2 adsorption, which can increase conversion and C 5+ selectivity as well as decrease CH 4 selectivity. 97 Delafossite (CuFeO 2 ) derived Fe–Cu catalysts give C 5+ hydrocarbon selectivity as high as 66.3% among all hydrocarbons with 31% of C 2–4 (o/p = 7.3) and only 2.7% of methane under 300 °C, 1.0 MPa, 1800 mL g –1 h –1 , and H 2 /CO 2 = 3. 98 The presence of Cu + species in CuFeO 2 promotes the reduction of the Fe catalyst and thus promotes the formation of the FTS active phase (χ-Fe 5 C 2 ).…”

Synergistic Effect of Alkali Na and K Promoter on Fe-Co-Cu-Al Catalysts for CO2 Hydrogenation to Light Hydrocarbons

“…Additionally, these two peaks become for FCCA-N simultaneously modified by Na and K as promoters. In any c and H2-TPR results have proved that Na and/or K modification leads to the e of metallic Fe@Cu or Fe-Co@Cu alloy in FeCoCuAl catalysts, because alk ions can provide an electron-rich environment [35]. Therefore, the obvious adsorption peak bands in a temperature range of 200-420 °C are attributed tion of active H formed by dissociative adsorption on metallic Fe@Cu or F species.…”