Fast oxygen ion migration in Cu–In–oxide bulk and its utilization for effective CO2 conversion at lower temperature

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 Cu–In–structured oxide, even at lower temperatures. Results show that novel Cu–In2O3 structured oxide can show a remarkably higher CO2 splitting rate than ever reported. Various analyses revealed that RWGS‑CL on Cu–In2O3 is derived from redox between Cu–In2O3 and CuxIny alloy. Key factors for high CO2 splitting were fast migration of oxide ions in alloy and the preferential oxidation of the interface of alloy–In2O3 in the bulk of the particles. The findings reported herein can open up new avenues to achieve effective CO2 conversion at lower temperatures.

Download Full-text

Fast Oxygen Ion Migration in Cu–In–oxide Bulk and Its Utilization for Effective CO2 Conversion at Lower Temperature

10.26434/chemrxiv.12973844 ◽

2020 ◽

Author(s):

Takuma Higo ◽

Jun-Ichiro Makiura ◽

Yutaro Kurosawa ◽

Kota Murakami ◽

Shuhei Ogo ◽

...

Keyword(s):

Water Gas Shift ◽

Chemical Looping ◽

Key Factors ◽

Ion Migration ◽

Oxygen Ion ◽

Reverse Water Gas Shift ◽

Oxygen Ion Migration ◽

Lower Temperature ◽

Water Gas ◽

Oxide Ions

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 Cu–In–structured oxide, even at lower temperatures. Results show that novel Cu–In2O3 structured oxide can show a remarkably higher CO2 splitting rate than ever reported. Various analyses revealed that RWGS‑CL on Cu–In2O3 is derived from redox between Cu–In2O3 and CuxIny alloy. Key factors for high CO2 splitting were fast migration of oxide ions in alloy and the preferential oxidation of the interface of alloy–In2O3 in the bulk of the particles. The findings reported herein can open up new avenues to achieve effective CO2 conversion at lower temperatures.

Download Full-text

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

Catalysts ◽

10.3390/catal10091082 ◽

2020 ◽

Vol 10 (9) ◽

pp. 1082 ◽

Cited By ~ 1

Author(s):

Natalie Utsis ◽

Miron V. Landau ◽

Alexander Erenburg ◽

Moti Herskowitz

Keyword(s):

Surface Area ◽

Oxygen Vacancies ◽

Water Gas Shift ◽

Chemical Looping ◽

Direct Connection ◽

Co2 Conversion ◽

Reduction Temperature ◽

Reverse Water Gas Shift ◽

Rwgs Reaction ◽

Water Gas

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.

Download Full-text

Controlled template removal from nanocast La0.8Sr0.2FeO3 for enhanced CO2 conversion by reverse water gas shift chemical looping

Journal of CO2 Utilization ◽

10.1016/j.jcou.2021.101845 ◽

2021 ◽

pp. 101845

Author(s):

Ayeong Jo ◽

Yikyeom Kim ◽

Hyun Suk Lim ◽

Minbeom Lee ◽

Dohyung Kang ◽

...

Keyword(s):

Water Gas Shift ◽

Chemical Looping ◽

Co2 Conversion ◽

Template Removal ◽

Reverse Water Gas Shift ◽

Water Gas

Download Full-text

Combustion synthesis of copper ceria solid solution for CO2 conversion to CO via reverse water gas shift reaction

International Journal of Hydrogen Energy ◽

10.1016/j.ijhydene.2021.12.142 ◽

2022 ◽

Author(s):

Parisa Ebrahimi ◽

Anand Kumar ◽

Majeda Khraisheh

Keyword(s):

Solid Solution ◽

Combustion Synthesis ◽

Water Gas Shift ◽

Co2 Conversion ◽

Water Gas Shift Reaction ◽

Reverse Water Gas Shift ◽

Shift Reaction ◽

Water Gas

Download Full-text

Reverse Water–Gas Shift Chemical Looping Using a Core–Shell Structured Perovskite Oxygen Carrier

Energies ◽

10.3390/en13205324 ◽

2020 ◽

Vol 13 (20) ◽

pp. 5324

Author(s):

Minbeom Lee ◽

Yikyeom Kim ◽

Hyun Suk Lim ◽

Ayeong Jo ◽

Dohyung Kang ◽

...

Keyword(s):

Metal Oxide ◽

Oxygen Carrier ◽

Dark Field ◽

Water Gas Shift ◽

Unit Weight ◽

Core Shell ◽

Chemical Looping ◽

Oxygen Carriers ◽

Reverse Water Gas Shift ◽

Water Gas

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.

Download Full-text