Characterization of oxide-supported Cu by infrared measurements on adsorbed CO

Nielsen, Niels D.; Smitshuysen, Thomas E. L.; Damsgaard, Christian Danvad; Jensen, Anker Degn; Christensen, Jakob Munkholt

doi:10.1016/j.susc.2020.121725

Cited by 33 publications

(28 citation statements)

References 96 publications

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“…A similar effect was also observed by comparing the spectra recorded at 250 °C where formate is the electro-withdrawing adsorbate. 70 − 72 It was found that the intensity of the HCOO-Cu band on Cu(5)/CeO 2 and Cu(5)/ZnO–CeO 2 (0.05) were much higher than on Cu(5)/ZnO, indicating a higher formate coverage on the Ce-containing catalysts.…”

Section: Resultsmentioning

confidence: 99%

Flame Synthesis of Cu/ZnO–CeO₂ Catalysts: Synergistic Metal–Support Interactions Promote CH₃OH Selectivity in CO₂ Hydrogenation

et al. 2021

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The hydrogenation of CO 2 to CH 3 OH is an important reaction for future renewable energy scenarios. Herein, we compare Cu/ZnO, Cu/CeO 2 , and Cu/ZnO–CeO 2 catalysts prepared by flame spray pyrolysis. The Cu loading and support composition were varied to understand the role of Cu–ZnO and Cu–CeO 2 interactions. CeO 2 addition improves Cu dispersion with respect to ZnO, owing to stronger Cu–CeO 2 interactions. The ternary Cu/ZnO–CeO 2 catalysts displayed a substantially higher CH 3 OH selectivity than binary Cu/CeO 2 and Cu/ZnO catalysts. The high CH 3 OH selectivity in comparison with a commercial Cu–ZnO catalyst is also confirmed for Cu/ZnO–CeO 2 catalyst prepared with high Cu loading (∼40 wt %). In situ IR spectroscopy was used to probe metal–support interactions in the reduced catalysts and to gain insight into CO 2 hydrogenation over the Cu–Zn–Ce oxide catalysts. The higher CH 3 OH selectivity can be explained by synergistic Cu–CeO 2 and Cu–ZnO interactions. Cu–ZnO interactions promote CO 2 hydrogenation to CH 3 OH by Zn-decorated Cu active sites. Cu–CeO 2 interactions inhibit the reverse water–gas shift reaction due to a high formate coverage of Cu and a high rate of hydrogenation of the CO intermediate to CH 3 OH. These insights emphasize the potential of fine-tuning metal–support interactions to develop improved Cu-based catalysts for CO 2 hydrogenation to CH 3 OH.

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Section: Resultsmentioning

confidence: 99%

Flame Synthesis of Cu/ZnO–CeO₂ Catalysts: Synergistic Metal–Support Interactions Promote CH₃OH Selectivity in CO₂ Hydrogenation

et al. 2021

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“…ZnO as support uniquely influences by shifting the adsorption to lower frequencies, attributed to some sort of interaction with Cu. Moreover, such bands are less intense in comparison with those without the presence of ZnO [175]. The presence of subsurface oxygen was found to modify the electronic structure of Cu and enhance the adsorption of CO, resulting in the existence of Cu in the zero oxidation state according to an investigation using in situ ambient pressure XPS [137].…”

Section: Functions Of Various Cu Species At Different Oxidation States (I) Metallic Cumentioning

confidence: 96%

“…c. The dissociative adsorption of H 2 and reaction with intermediate to form methoxy species on the Cu surface. The CO bond frequency is highly sensitive to the charge on the adsorption site of Cu catalysts [175,206]. Adsorption of CO was observed on reduced Cu/ZnO/SiO 2 and Cu/SiO 2 catalysts [206].…”

Section: (Iii) Cu 2 O (Cu + )mentioning

confidence: 99%

“…A high CO adsorption was recorded on Cu + sites while the adsorption on Cu 0 sites was moderate. The Cu/ZnO/Al 2 O 3 catalyst showed CO adsorption band at frequencies (2065-2094 cm −1 ) [38,175,207,208]. Upon surface coverage with adsorbate such as formed formate during CO 2 reduction to methanol, electron transfer (withdrawing effect of formate) takes effect, leading to an upward shift in the CO stretching frequency.…”

Section: (Iii) Cu 2 O (Cu + )mentioning

confidence: 99%

“…Measured VC-O associated with metallic Cu on reduced Cu-based catalysts during CO-adsorption at 276 K[175].…”

mentioning

confidence: 99%

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CO<sub>2</sub> Valorization Reactions over Cu-Based Catalysts: Characterization and the Nature of Active Sites

Etim¹,

Semiat²,

Zhong³

2021

AJCHE

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Active sites are the individual reactors at the molecular scale distributed on the heterogeneous catalyst surface. To a large extent, they determine the catalytic performances and the reaction pathway of a reaction. Therefore, understanding the nature and structure of the actives sites is crucial to improve and develop novel, robust and practical catalysts. The wide application of state-of-the-art characterization techniques these years makes it possible to obtain crucial information about the active sites for some catalysts. The Cu-based catalysts are widely used for water gas shift (WGS) and methanol synthesis from syngas (CO + H 2 ). Although having some technical issues in the direct conversion of CO 2 into value-added products, they are still promising for this reaction to mitigate CO 2 concentration in the atmosphere. In the last several years, intensive efforts have been made to study Cu-based catalysts, and substantial progress has been achieved in understanding their active sites and the reaction mechanism. This review discusses the structure and nature of active sites of Cu-based catalysts for CO 2 valorization in thermo-, photo-, and electro-catalysis. We present the characterization results of different types of Cu-based catalysts applied in these processes, unravel their active sites and structures, and figure out the most important and critical factors that drive the reactions on the sites. The principle and applications of various characterization techniques are also briefly analyzed and compared. It is expected to provide fundamental insights and perspectives for designing highly active and efficient catalysts for CO 2 conversion.

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Photo‐thermal Cooperative Carbonylation of Ethanol with CO₂ on Cu₂O‐SrTiCuO_3‐x

Zhang,

Shang,

et al. 2023

Angewandte Chemie

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Carbonylation of ethanol with CO2 as carbonyl source into value‐added esters is of considerable significance and interest, while remains of great challenge due to the harsh conditions for activation of inert CO2 in that the harsh conditions result in undesired activation of α‐C‐H and even cleavage of C‐C bond in ethanol to deteriorate the specific activation of O‐H bond. Herein, we propose a photo‐thermal cooperative strategy for carbonylation of ethanol with CO2, in which CO2 is activated to reactive CO via photo‐catalysis with the assistance of *H from thermally‐catalyzed dissociation of alcoholic O‐H bond. To achieve this proposal, an interfacial site and oxygen vacancy both abundant SrTiCuO3‐x supported Cu2O (Cu2O‐SrTiCuO3‐x) has been designed. A production of up to 320 μmol g‐1 h‐1 for ethyl formate with a selectivity of 85.6% to targeted alcoholic O‐H activation has been afforded in photo‐thermal assisted gas‐solid process under 3.29 W cm‐1 of UV‐Vis light irradiation (144 oC) and 0.2 MPa CO2. In the photo‐driven activation of CO2 and following carbonylation, CO2 activation energy decreases to 12.6 kJ mol‐1, and the cleavage of alcoholic α‐C‐H bond has been suppressed.

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Characterization of oxide-supported Cu by infrared measurements on adsorbed CO

Cited by 33 publications

References 96 publications

Flame Synthesis of Cu/ZnO–CeO₂ Catalysts: Synergistic Metal–Support Interactions Promote CH₃OH Selectivity in CO₂ Hydrogenation

Flame Synthesis of Cu/ZnO–CeO₂ Catalysts: Synergistic Metal–Support Interactions Promote CH₃OH Selectivity in CO₂ Hydrogenation

CO<sub>2</sub> Valorization Reactions over Cu-Based Catalysts: Characterization and the Nature of Active Sites

Photo‐thermal Cooperative Carbonylation of Ethanol with CO₂ on Cu₂O‐SrTiCuO_3‐x

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Characterization of oxide-supported Cu by infrared measurements on adsorbed CO

Cited by 33 publications

References 96 publications

Flame Synthesis of Cu/ZnO–CeO2 Catalysts: Synergistic Metal–Support Interactions Promote CH3OH Selectivity in CO2 Hydrogenation

Flame Synthesis of Cu/ZnO–CeO2 Catalysts: Synergistic Metal–Support Interactions Promote CH3OH Selectivity in CO2 Hydrogenation

CO&lt;sub&gt;2&lt;/sub&gt; Valorization Reactions over Cu-Based Catalysts: Characterization and the Nature of Active Sites

Photo‐thermal Cooperative Carbonylation of Ethanol with CO2 on Cu2O‐SrTiCuO3‐x

Contact Info

Product

Resources

About

Flame Synthesis of Cu/ZnO–CeO₂ Catalysts: Synergistic Metal–Support Interactions Promote CH₃OH Selectivity in CO₂ Hydrogenation

Flame Synthesis of Cu/ZnO–CeO₂ Catalysts: Synergistic Metal–Support Interactions Promote CH₃OH Selectivity in CO₂ Hydrogenation

CO<sub>2</sub> Valorization Reactions over Cu-Based Catalysts: Characterization and the Nature of Active Sites

Photo‐thermal Cooperative Carbonylation of Ethanol with CO₂ on Cu₂O‐SrTiCuO_3‐x