Unravelling the active sites and structure-activity relationship on Cu–ZnO–Al2O3 based catalysts for water-gas shift reaction

Ahn, Soonho; Kim, Kyoung-Jin; Kim, Beom-Jun; Shim, Jae-Oh; Jang, Won-Jun; Roh, Hyun-Seog

doi:10.1016/j.apcatb.2022.122320

Cited by 25 publications

(9 citation statements)

References 39 publications

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“…Cu/ZnO/Al 2 O 3 is an industrial catalyst employed in the WGS reaction, which achieved a ∼42% CO conversion at 300 °C with a high Cu loading. A comparison between the reaction rate-per-unit mass Cu reveals that CuZnAl-10 is ∼5 times higher than Cu/ZnO/Al 2 O 3 (Figure ), and the superior WGS performance compared to reported Cu-based catalysts. ,,,,,,,– In addition, once CuZnAl-10 was evaluated at a low space velocity of 18,000 mL·g cat –1 ·h –1 , a good catalytic activity with a CO conversion of ∼90% was obtained at low temperature (200 °C) (Figure S2), which indicates its potential applications for the low-temperature WGS reaction.…”

Section: Resultsmentioning

confidence: 95%

“…For the WGS reaction, Cu 0 and Cu + species are recognized as the active sites for Cu-based catalysts. ,– Currently, the synergetic effect between Cu 0 and Cu + species has been reported, wherein Cu + species are responsible for the adsorption of CO, and Cu 0 nanoparticles act as active sites for the dissociation of water. , Nonetheless, the regulation of Cu + and Cu 0 is commonly reliant on the Cu content or pretreatment parameters. ,,,, To further enhance the catalytic activity under optimal conditions, the introduction of promoters, such as Zn species, , is imperative. The function of ZnO in the Cu–Zn–Al catalysts is currently subject to varying perspectives.…”

Section: Introductionmentioning

confidence: 99%

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Facile Synthesis of Efficient and Robust Cu–Zn–Al Catalysts by the Sol–Gel Method for the Water–Gas Shift Reaction

Ye,

Song,

Cui

et al. 2023

Ind. Eng. Chem. Res.

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The water–gas shift reaction is widely employed in hydrogen production. Herein, we report a facile sol–gel method for preparing Cu–Zn–Al catalysts with significantly suppressed Cu and Zn contents compared with commercial Cu/ZnO/Al2O3. We discover that Zn species are not only to augment the proportion of Cu+ species to increase the concentration of adsorbed CO on catalysts, thereby promoting the formation of intermediate species; but also to decrease the size of Cu0 nanoparticles, which accelerates the decomposition of reaction intermediates and the desorption of products. Both advantages significantly improve the performance and stability of the catalysts, especially for CuZnAl-10. It contains 12 wt % Cu and 1.2 wt % Zn with the optimal Cu+/Cu0 ratio of 1.2 and exhibits ∼5 times higher reaction rate compared to Cu/ZnO/Al2O3 at 200 °C. In situ characterization results further demonstrate that the as-prepared Cu–Zn–Al catalysts follow an association mechanism.

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Section: Resultsmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

Facile Synthesis of Efficient and Robust Cu–Zn–Al Catalysts by the Sol–Gel Method for the Water–Gas Shift Reaction

Ye,

Song,

Cui

et al. 2023

Ind. Eng. Chem. Res.

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“…In fact, due to the strong interaction with the metal and oxides, it was difficult for the metal to exist in a fully metallic state on the catalytic interface. Therefore, there might be rich Cu + sites at the catalyst surface which could facilitate the adsorption and activation of CO [35–37] . In order to detect the surface states of Cu species in the reaction process, the quasi in situ XPS measurement was measured.…”

Section: Resultsmentioning

confidence: 99%

“…[34] In fact, due to the strong interaction with the metal and oxides, it was difficult for the metal to exist in a fully metallic state on the catalytic interface. Therefore, there might be rich Cu + sites at the catalyst surface which could facilitate the adsorption and activation of CO. [35][36][37] In order to detect the surface states of Cu species in the reaction process, the quasi in situ XPS measurement was measured. After the H 2 pretreatment, the reaction gas flow was injected into the sample room for 1 hour at 300 °C, and then the experiment was conducted by directly vacuuming at 300 °C from the sample preparation chamber.…”

Section: Formation Of the Inverse Active Interfacementioning

confidence: 99%

Dynamic Structural Evolution of CeO₂ in CuO−CeO₂ Catalyst Revealed by In Situ Spectroscopy

Wu,

Wang,

Wang

et al. 2023

ChemCatChem

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The oxides and active metals at the interface synergistically activate reactants and thus promote the reaction, but the interface structure often changes dynamically during the reaction. In the conventional supported catalysts, the metals at the interface have been extensively studied, while the structural evolution of oxides is often overlooked. In this work, we design the CeO2‐CuO inverse catalysts to reveal the dynamic structure evolution of CeO2 in the CeO2‐CuO system during the water gas shift (WGS) reaction by in situ Raman, in situ XRD, quasi in situ XPS, and near ambient pressure XPS (NAP‐XPS). We find that CeO2 is partially concealed in the CuO phase in the un‐pretreated catalyst and gradually exposed to the surface, forming an inverse CeOx/Cu structure during the reducing process. This structure exhibits a high catalytic activity in the WGS reaction and remains durable under the reductive conditions. When the inverse CeOx/Cu structure is exposed to the non‐redox conditions, the reconfiguration of the reduced oxide is observed which is caused by the oxygen migration of CeO2. This work explores the structure evolution of CeO2 in CeO2‐CuO inverse catalyst under different conditions and provides a reference for monitoring the dynamic changes of oxide structure.

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“…Hydrogen can be produced from various sources, such as natural gas, coal, waste, and water. , Recently, hydrogen production from waste has emerged as a research focus area. The water gas shift (WGS; CO + H 2 O → H 2 + CO 2 ) reaction of synthesis gas derived from waste gasification is essential for hydrogen production …”

Section: Introductionmentioning

confidence: 99%

Improving the Performance of a Co-CeO₂ Catalyst for Hydrogen Production via Water Gas Shift Reaction by Addition of Transition Metal Oxides

Kim,

Jeong,

Cheon

et al. 2024

Energy Fuels

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The hydrogen production from combustible waste is attracting attention because of the increasing interest in clean and renewable hydrogen production. To produce hydrogen from combustible waste, gasification and water gas shift reaction processes are required. Syngas, which mainly consists of hydrogen and carbon monoxide, is generated by gasification of combustible waste. The water gas shift reaction is applied to produce additional hydrogen from carbon monoxide in waste-derived syngas. The performance of catalysts is important to achieve reasonable process efficiency. Co-based catalysts were applied to the water gas shift reaction because Co has significant capability for CO oxidation and high reaction rates when it is used as an active metal. However, it was necessary to enhance the stability of Cobased catalysts. Here, different transition metal oxides (TiO 2 , ZrO 2 , V 2 O 5 , and Nb 2 O 5 ) are used as promoters to enhance the Co-CeO 2 catalyst performance. To investigate the effects of promoters on the catalytic performance, various properties are characterized. According to the analysis results, the physicochemical properties, which determine the catalytic performance, were influenced by the addition of transition metal oxides. Among the synthesized catalysts, the Nb 2 O 5 -promoted Co-CeO 2 catalyst exhibited the best catalytic performance. As a result, the Nb 2 O 5 promoter is the most effective to improve the catalytic activity and stability of the Co-CeO 2 catalyst for high-temperature water gas shift reaction to produce hydrogen from waste-derived syngas. The higher CO conversion is related to the numerous oxygen vacancies and high Co dispersion, while stability is related to strong interactions between Co and the support. These findings are expected to aid the development of catalysts by confirming physicochemical properties relating with catalytic performance.

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Unravelling the active sites and structure-activity relationship on Cu–ZnO–Al2O3 based catalysts for water-gas shift reaction

Cited by 25 publications

References 39 publications

Facile Synthesis of Efficient and Robust Cu–Zn–Al Catalysts by the Sol–Gel Method for the Water–Gas Shift Reaction

Facile Synthesis of Efficient and Robust Cu–Zn–Al Catalysts by the Sol–Gel Method for the Water–Gas Shift Reaction

Dynamic Structural Evolution of CeO₂ in CuO−CeO₂ Catalyst Revealed by In Situ Spectroscopy

Improving the Performance of a Co-CeO₂ Catalyst for Hydrogen Production via Water Gas Shift Reaction by Addition of Transition Metal Oxides

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Unravelling the active sites and structure-activity relationship on Cu–ZnO–Al2O3 based catalysts for water-gas shift reaction

Cited by 25 publications

References 39 publications

Facile Synthesis of Efficient and Robust Cu–Zn–Al Catalysts by the Sol–Gel Method for the Water–Gas Shift Reaction

Facile Synthesis of Efficient and Robust Cu–Zn–Al Catalysts by the Sol–Gel Method for the Water–Gas Shift Reaction

Dynamic Structural Evolution of CeO2 in CuO−CeO2 Catalyst Revealed by In Situ Spectroscopy

Improving the Performance of a Co-CeO2 Catalyst for Hydrogen Production via Water Gas Shift Reaction by Addition of Transition Metal Oxides

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Product

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Dynamic Structural Evolution of CeO₂ in CuO−CeO₂ Catalyst Revealed by In Situ Spectroscopy

Improving the Performance of a Co-CeO₂ Catalyst for Hydrogen Production via Water Gas Shift Reaction by Addition of Transition Metal Oxides