Nickel-catalyzed methanation reactions studied with an in situ magnetic induction method: Experiments and modeling

Jiang

et al. 2018

Ind. Eng. Chem. Res.

104

This paper reports on Fe–Cu bimetallic catalysts supported on γ-alumina for selective CO2 hydrogenation to olefin-rich C2 + hydrocarbons. A strong synergetic promoting effect on C2 + hydrocarbon synthesis was observed over Fe–Cu bimetallic catalysts when the Cu/(Cu + Fe) atomic ratio was 0.17. Compared to monometallic Fe catalyst, the Fe–Cu bimetallic catalyst significantly enhances C2–C7 hydrocarbon formation and suppresses the formation of undesired CH4. The addition of K into Fe–Cu bimetallic catalysts inhibits the methanation and further enhances the formation of C2 + hydrocarbons in the meantime. The synthesis of olefin-rich C2–C4 hydrocarbons from CO2/H2 was achieved by using K-promoted Fe–Cu/Al2O3 catalysts with higher K/Fe atomic ratios (e.g., K/Fe ≥ 0.5), where the selectivity of C2–C4 olefin contents was even higher than K-promoted Fe–Co catalysts under the same reaction conditions.

Section: Introductionmentioning

confidence: 99%

Fe–Cu Bimetallic Catalysts for Selective CO₂ Hydrogenation to Olefin-Rich C₂⁺ Hydrocarbons

Jiang

et al. 2018

Ind. Eng. Chem. Res.

104

“…CO 2 hydrogenation provides an alternative path to hydrocarbon products currently produced from petroleum, as it utilizes abundant CO 2 as a chemical feedstock and hydrogen as the coreactant. − Fe-based catalysts have shown good performance for CO 2 hydrogenation processes including reverse water–gas shift (RWGS) followed by Fischer–Tropsch (F-T) synthesis. − However, Fe catalysts show low selectivity to industrially important light olefins and higher hydrocarbons, which represents a general limitation in F-T synthesis . Many of the catalysts which are useful in F-T synthesis are also capable of catalyzing the hydrogenation of CO 2 to hydrocarbons, such as Co-, Ni-, and Fe-based catalysts. − Co catalysts are widely used in F-T synthesis due to high performance-cost evaluation. However, upon switching the feed from syngas to a CO 2 and H 2 mixture, Co performs as a methanation catalyst rather than as an F-T catalyst .…”

Section: Introductionmentioning

confidence: 99%

Mechanistic Insight into C–C Coupling over Fe–Cu Bimetallic Catalysts in CO₂ Hydrogenation

et al. 2017

Density functional theory (DFT) calculations were carried out to investigate the mechanism of CO2 hydrogenation in production of C1 and C2 hydrocarbons over Cu–Fe bimetallic catalyst. CH* is found to be the most favorable monomeric species for production of CH4 and C2H4 via C–C coupling of two CH* species and subsequent hydrogenation. On the bimetallic Cu–Fe(100) surface at 4/9 ML Cu coverage, the energetically preferred path for CH* formation goes through CO2* → HCOO* → HCOOH* → HCO* → HCOH* → CH*, in which both the HCOO* → HCOOH* and HCO* → HCOH* steps have substantial barriers. The bimetallic surface suppresses CH4 formation and is more selective to C2H4 due to the higher hydrogenation barrier of CH2* species relative to those for C–C coupling and CH–CH* conversion to C2H4. On monometallic Fe(100) surface, CH* formation goes through a path of CO2* → CO* → HCO* → HCOH* → CH*, different from that identified on Cu–Fe(100). The hydrogenation of HCO* to HCOH* is the rate-limiting step that controls CO2 conversion to CH4 and C2H4. CH4 formation is kinetically more favored, with a 0.3 eV lower energy barrier, than C2H4 formation. The bimetallic combination of Cu and Fe enhances CO2 conversion by reducing the kinetic barriers, and alters the selectivity preference to more valuable C2H4 from CH4 on monometallic Fe surface. C2H6 can be produced from further hydrogenation of C2H4 with moderate barriers.

Catalysis Communications

“…The catalytic systems containing Ni, Ru and Rh were the most effective [3][4][5][6]. Though much cheaper than Ru and Rh, Ni-based catalysts suffer from deactivation at low temperatures due to the strong interaction of Ni with CO and the formation of mobile carbonyls, which leads to the sintering of the active phase [7,8]. The choice of the support is furthermore important since it may determine the adsorptive properties of the catalytic system and the interaction support-active phase [2].…”

Section: Introductionmentioning

confidence: 99%

Novel Ni-La-hydrotalcite derived catalysts for CO2 methanation

Wierzbicki

Dębek

Motak

et al. 2016

153

A series of hydrotalcite-derived mixed oxides containing Ni/Mg/La/Al obtained by thermal decomposition were characterized by XRD, CO 2-TPD and H 2-TPR. The results confirm the formation of periclase-like materials, and the addition of lanthanum resulted in the formation of a separate phase. The incorporation of 2 wt.% of lanthanum leads to an increase of the catalytic performance at temperatures from 250 to 300°C with CO 2 conversion of 46.5-75% and CH 4 selectivity of 99-98%. The activity is directly connected with basicity that increases with the incorporation of La into the HT-derived catalysts.