Single-stage water gas shift reaction over structural modified Cu–Ce catalysts at medium temperatures: Synthesis and catalyst performance

Roshan, Ali Cheshmeh; Irankhah, Abdullah; Mahmoudizadeh, Masoud; Arandiyan, Hamidreza

doi:10.1016/j.cherd.2018.02.038

Cited by 13 publications

(3 citation statements)

References 34 publications

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“…Reduction properties of the three Cu 2 O samples were determined by H 2 -TPR, and the results are shown in Figure 7. Since there were no other reducible metal oxide components in the three Cu 2 O samples, the hydrogen consumption peaks of each sample corresponded to the reduction of Cu + or a small amount of Cu 2+ to metallic Cu [51][52][53] a N, coordination number; R, the distance between the absorber and backscattered atoms; Δσ 2 , Debye-Waller factor. Error bounds (accuracies) characterizing the structural parameters obtained by EXAFS spectroscopy are estimated to be as follows: N, ~20%; R, ~0.02; Δσ 2 , ~20%.…”

Section: The Reducibility Of Cu 2 O Catalystsmentioning

confidence: 99%

“…Reduction properties of the three Cu2O samples were determined by H2-TPR, and the results are shown in Figure 7. Since there were no other reducible metal oxide components in the three Cu2O samples, the hydrogen consumption peaks of each sample corresponded to the reduction of Cu + or a small amount of Cu 2+ to metallic Cu [51][52][53]. The reduction peaks reached the maximum H2 consumption at 190 °C for Cu2O-NO3, 275 °C for Cu2O-Cl(1) and 340 °C for Cu2O-Cl(2).…”

Section: The Reducibility Of Cu2o Catalystsmentioning

confidence: 99%

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High-Performance Chlorine-Doped Cu2O Catalysts for the Ethynylation of Formaldehyde

Gao

Yang

et al. 2019

Processes

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The in situ formed Cu+ species serve as active sites in the ethynylation of formaldehyde. The key problem that needs to be solved in this process is how to avoid excessive reduction of Cu2+ to inactive metallic Cu, which tends to decrease the catalytic activity. In this work, Cl−-modified Cu2O catalysts with different Cl content were prepared by co-precipitation. The characterization results demonstrated that Cl− remained in the lattice structure of Cu2O, inducing the expansion of the Cu2O lattice and the enhancement of the Cu–O bond strength. Consequently, the reduction of Cu+ to Cu0 was effectively prevented in reductive media. Moreover, the activity and stability of Cu2O were significantly improved. The Cl− modification increased the yield of 1,4-butynediol (BD) from 73% to 94% at a reaction temperature of 90 °C. More importantly, the BD yield of Cl− modified Cu2O was still as high as 86% during the ten-cycle experiment, whereas the BD yield of Cu2O in the absence of Cl− decreased sharply to 17% at the same reaction conditions. This work provides a simple strategy to stabilize Cu+ in reductive media.

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Section: The Reducibility Of Cu 2 O Catalystsmentioning

confidence: 99%

“…Reduction properties of the three Cu2O samples were determined by H2-TPR, and the results are shown in Figure 7. Since there were no other reducible metal oxide components in the three Cu2O samples, the hydrogen consumption peaks of each sample corresponded to the reduction of Cu + or a small amount of Cu 2+ to metallic Cu [51][52][53]. The reduction peaks reached the maximum H2 consumption at 190 °C for Cu2O-NO3, 275 °C for Cu2O-Cl(1) and 340 °C for Cu2O-Cl(2).…”

Section: The Reducibility Of Cu2o Catalystsmentioning

confidence: 99%

High-Performance Chlorine-Doped Cu2O Catalysts for the Ethynylation of Formaldehyde

Gao

Yang

et al. 2019

Processes

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“…It was assumed that small copper clusters are the active sites for the low-temperature WGS reaction over copper-based catalysts [2]. The presence of very small copper particles contributed to the highest CO conversion, while their sintering into larger agglomerates negatively affected the catalyst behavior [25]. The same statement is valid for the gold-based catalysts.…”

Section: Catalytic Activity Measurementsmentioning

confidence: 99%

Promotional Effect of Gold on the WGS Activity of Alumina-Supported Copper-Manganese Mixed Oxides

et al. 2018

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The water-gas shift (WGS) reaction is a well-known industrial process used for the production of hydrogen. During the last few decades, it has attracted renewed attention due to the need for high-purity hydrogen for fuel-cell processing systems. The aim of the present study was to develop a cost-effective and catalytically efficient formulation that combined the advantageous properties of transition metal oxides and gold nanoparticles. Alumina-supported copper- manganese mixed oxides were prepared by wet impregnation. The deposition-precipitation method was used for the synthesis of gold catalysts. The effect of the Cu:Mn molar ratio and the role of Au addition on the WGS reaction’s performance was evaluated. Considerable emphasis was put on the characterization of the as-prepared and WGS-tested samples by means of a number of physicochemical methods (X-ray powder diffraction, high-resolution transmission electron microscopy, electron paramagnetic resonance, X-ray photoelectron spectroscopy, and temperature-programmed reduction) in order to explain the relationship between the structure and the reductive and WGS behavior. Catalytic tests revealed the promotional effect of gold addition. The best performance of the gold-promoted sample with a higher Cu content, i.e., a Cu:Mn molar ratio of 2:1 might be related to the beneficial role of Au on the spinel decomposition and the highly dispersed copper particle formation during the reaction, thus, ensuring the presence of two highly dispersed active metallic phases. High-surface-area alumina that was modified with a surface fraction of Cu–Mn mixed oxides favored the stabilization of finely dispersed gold particles. These new catalytic systems are very promising for practical applications due to their economic viability because the composition mainly includes alumina (80%).

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Preferential CO Oxidation on a Highly Active Cu Single Atom Catalyst Supported by Ce−TiO_x

et al. 2022

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A heterogeneous single-atom catalyst (SAC) based on a tiny Cu loading (0.05 wt.%) supported on CeO 2 À TiO 2 (Ce/Ti = 0.18) shows very high Cu mass-normalized CO oxidation activity, 100 % selectivity for CO 2 between 60 and 100 °C and essentially no deactivation during 17 h on stream in the preferential oxidation of CO (PROX) at 120 °C. Based on state of the art, this catalyst is among the most active and PROX-selective catalysts. Employing a combination of ex-situ and operando methods, we infer that the isolated Cu single sites are incorporated with redox-active Cu 2 + À OÀ Ce 4 + .Cu + À &À Ce 3 + moieties connected by labile oxygen and are exposed on the surface of highly dispersed ceria. This high dispersion is promoted by TiO 2 which itself does not participate in redox steps during PROX, as Ti ions remain essentially tetravalent while Cu and Ce undergo reversible redox shuttles.

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Single-stage water gas shift reaction over structural modified Cu–Ce catalysts at medium temperatures: Synthesis and catalyst performance

Cited by 13 publications

References 34 publications

High-Performance Chlorine-Doped Cu2O Catalysts for the Ethynylation of Formaldehyde

High-Performance Chlorine-Doped Cu2O Catalysts for the Ethynylation of Formaldehyde

Promotional Effect of Gold on the WGS Activity of Alumina-Supported Copper-Manganese Mixed Oxides

Preferential CO Oxidation on a Highly Active Cu Single Atom Catalyst Supported by Ce−TiO_x

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Single-stage water gas shift reaction over structural modified Cu–Ce catalysts at medium temperatures: Synthesis and catalyst performance

Cited by 13 publications

References 34 publications

High-Performance Chlorine-Doped Cu2O Catalysts for the Ethynylation of Formaldehyde

High-Performance Chlorine-Doped Cu2O Catalysts for the Ethynylation of Formaldehyde

Promotional Effect of Gold on the WGS Activity of Alumina-Supported Copper-Manganese Mixed Oxides

Preferential CO Oxidation on a Highly Active Cu Single Atom Catalyst Supported by Ce−TiOx

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Preferential CO Oxidation on a Highly Active Cu Single Atom Catalyst Supported by Ce−TiO_x