scholarly journals Reverse Water Gas Shift by Chemical Looping with Iron-Substituted Hexaaluminate Catalysts

Catalysts ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1082 ◽  
Author(s):  
Natalie Utsis ◽  
Miron V. Landau ◽  
Alexander Erenburg ◽  
Moti Herskowitz

The Fe-substituted Ba-hexaaluminates (BaFeHAl) are active catalysts for reverse water-gas shift (RWGS) reaction conducted in chemical looping mode. Increasing of the degree of substitution of Al3+ for Fe3+ ions in co-precipitated BaHAl from 60% (BaFeHAl) to 100% (BaFe-hexaferrite, BaFeHF), growing its surface area from 5 to 30 m2/g, and promotion with potassium increased the CO capacity in isothermal RWGS-CL runs at 350–450 °C, where the hexaaluminate/hexaferrite structure is stable. Increasing H2-reduction temperature converts BaFeHAl to a thermally stable BaFeHF modification that contains additional Ba-O-Fe bridges in its structure, reinforcing the connection between alternatively stacked spinel blocks. This material displayed the highest CO capacity of 400 µmol/g at isothermal RWGS-CL run conducted at 550 °C due to increased concentration of oxygen vacancies reflected by greater surface Fe2+/Fe3+ ratio detected by XPS. The results demonstrate direct connection between CO capacity measured in RWGS-CL experiments and calculated CO2 conversion.

2021 ◽  
Author(s):  
Jun-Ichiro Makiura ◽  
Takuma Higo ◽  
Yutaro Kurosawa ◽  
Kota Murakami ◽  
Shuhei Ogo ◽  
...  

Efficient activation of CO2 at low temperature was achieved by reverse water–gas shift via chemical looping (RWGS-CL) by virtue of fast oxygen ion migration in a Cu–In structured oxide, even at lower temperatures.


Catalysts ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1076
Author(s):  
Lucy Idowu Ajakaiye Jensen ◽  
Sara Blomberg ◽  
Christian Hulteberg

Catalytic conversion of CO2 to CO using reverse water gas shift (RWGS) reaction is a key intermediate step for many CO2 utilization processes. RWGS followed by well-known synthesis gas conversion may emerge as a potential approach to convert CO2 to valuable chemicals and fuels. Nickel (Ni) based catalysts with ceria-zirconia (Ce-Zr) support can be used to tune the metal-support interactions, resulting in a potentially enhanced CO2 hydrogenation rate and elongation of the catalyst lifespan. The thermodynamics of RWGS reaction is favored at high temperature for CO2 conversion. In this paper the effect of Palladium (Pd) and Iridium (Ir) as promoters in the activity of 10 wt%Ni 2 wt%Pd 0.1wt%Ir/CeZrO2 catalyst for the reverse water gas shift reaction was investigated. RWGS was studied for different feed (CO2:H2) ratios. The new active interface between Ni, Pd and Ir particles is proposed to be an important factor in enhancing catalytic activity. 10 wt%Ni 2 wt%Pd 0.1 wt%Ir/CeZrO2 catalyst showed a better activity with CO2 conversion of 52.4% and a CO selectivity of 98% for H2:CO2 (1:1) compared to the activity of 10%Ni/CeZrO2 with CO2 conversion of 49.9% and a CO selectivity of 93%. The catalytic activity for different feed ratios using 10 wt%Ni 2 wt%Pd 0.1 wt%Ir/CeZrO2 were also studied. The use of palladium and iridium boosts the stability and life span of the Ni-based catalysts. This indicates that the catalyst could be used potentially to design RWGS reactors for CO2 utilization units.


Author(s):  
Daiya Kobayashi ◽  
Hirokazu Kobayashi ◽  
Kohei Kusada ◽  
Tomokazu Yamamoto ◽  
Takaaki Toriyama ◽  
...  

We report PtW solid-solution alloy nanoparticles (NPs) as a reverse water-gas shift (RWGS) reaction catalyst for the first time. Atomic-level alloying of Pt and W significantly enhanced the RWGS reaction activity of Pt NPs.


2004 ◽  
Vol 226 (2) ◽  
pp. 382-392 ◽  
Author(s):  
A GOGUET ◽  
F MEUNIER ◽  
J BREEN ◽  
R BURCH ◽  
M PETCH ◽  
...  

Energies ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 5324
Author(s):  
Minbeom Lee ◽  
Yikyeom Kim ◽  
Hyun Suk Lim ◽  
Ayeong Jo ◽  
Dohyung Kang ◽  
...  

Reverse water–gas shift chemical looping (RWGS-CL) offers a promising means of converting the greenhouse gas of CO2 to CO because of its relatively low operating temperatures and high CO selectivity without any side product. This paper introduces a core–shell structured oxygen carrier for RWGS-CL. The prepared oxygen carrier consists of a metal oxide core and perovskite shell, which was confirmed by inductively coupled plasma mass spectroscopy (ICP-MS), XPS, and high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) measurements. The perovskite-structured shell of the prepared oxygen carrier facilitates the formation and consumption of oxygen defects in the metal oxide core during H2-CO2 redox looping cycles. As a result, amounts of CO produced per unit weight of the core–shell structured oxygen carriers were higher than that of a simple perovskite oxygen carrier. Of the metal oxide cores tested, CeO2, NiO, Co3O4, and Co3O4-NiO, La0.75Sr0.25FeO3-encapsulated Co3O4-NiO was found to be the most promising oxygen carrier for RWGS-CL, because it was most productive in terms of CO production and exhibited long-term stability.


Author(s):  
Bin Shao ◽  
Guihua Hu ◽  
Khalil A.M. Alkebsi ◽  
Guanghua Ye ◽  
Xiaoqing Lin ◽  
...  

The integration of carbon capture and CO2 utilization could be a promising solution to the crisis of global warming. By integrating the calcium-looping (CaL) and the reverse-water-gas-shift (RWGS) reaction, a...


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