Composite Si-O-metal network catalysts with uneven electron distribution: Enhanced activity and electron transfer for catalytic ozonation of carbamazepine

Li, Shangyi; Wang, Jing; Ye, Yiyun; Li, Xukai; Gu, Fang; Li, Laisheng

doi:10.1016/j.apcatb.2019.118311

Cited by 45 publications

(27 citation statements)

References 51 publications

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“…The movement of Si–O–Si bonds indicates that Co enters the SiO 2 lattice and that Si–O–Co bonds exist in the materials, which destroys the symmetry of SiO 2 and causes the move of peak position. A similar phenomenon has been reported in other literature [ 44 , 45 ]. In addition, when n Co = 0.5, an additional peak is found located at 960 cm −1 and corresponding to the Si–O–Co vibration, suggesting that cobalt enters into the silica framework and forms the Si–O–Co bonds.…”

Section: Resultssupporting

confidence: 91%

“…It can be observed that, with the increases of n Co , the mean pore size increases, and the micropore volume decreases; the total pore volume and BET surface area increase until n Co = 0.08, after which they begin to decrease. This is because the added cobalt atoms exist in the form of Si–O–Co bonds in the SiO 2 skeleton, and the atomic radius of the cobalt atoms is larger than that of the silicon atoms, which plays a role in expanding the pores [ 45 ]. So, with the increase of n Co , the particle size, mean pore size, total pore volume, and surface area, the distribution of pore size becomes wider and shifts gradually to the direction of the mesopores.…”

Section: Resultsmentioning

confidence: 99%

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Sol-Gel Processed Cobalt-Doped Methylated Silica Membranes Calcined under N2 Atmosphere: Microstructure and Hydrogen Perm-Selectivity

Wang

Yang

et al. 2021

Materials

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Methyl-modified, cobalt-doped silica (Co/MSiO2) materials were synthesized by sol-gel technique calcined in N2 atmospheres, and membranes were made thereof by coating method. The effects of Co/Si molar ratio (nCo) on the physical-chemical constructions of Co/MSiO2 materials and microstructures of Co/MSiO2 membranes were systematically investigated. The gas permeance performance and hydrothermal stability of Co/MSiO2 membranes were also tested. The results show that the cobalt element in Co/MSiO2 material calcined at 400 °C exists not only as Si–O–Co bond but also as Co3O4 and CoO crystals. The introduction of metallic cobalt and methyl can enlarge the total pore volume and average pore size of the SiO2 membrane. The activation energy (Ea) values of H2, CO2, and N2 for Co/MSiO2 membranes are less than those for MSiO2 membranes. When operating at a pressure difference of 0.2 MPa and 200 °C compared with MSiO2 membrane, the permeances of H2, CO2, and N2 for Co/MSiO2 membrane with nCo = 0.08 increased by 1.17, 0.70, and 0.83 times, respectively, and the perm-selectivities of H2/CO2 and H2/N2 increased by 27.66% and 18.53%, respectively. After being steamed and thermally regenerated, the change of H2 permeance and H2 perm-selectivities for Co/MSiO2 membrane is much smaller than those for MSiO2 membrane.

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Section: Resultssupporting

confidence: 91%

Section: Resultsmentioning

confidence: 99%

Sol-Gel Processed Cobalt-Doped Methylated Silica Membranes Calcined under N2 Atmosphere: Microstructure and Hydrogen Perm-Selectivity

Wang

Yang

et al. 2021

Materials

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“…The bands around 292 and 479 cm −1 are attributed to the twisting vibrations and stretching vibrations of CoO bonds in amorphous CoO clusters. Notably, the unique band sited around 825 cm −1 is only observed for Co‐edta@S‐1 catalyst, which is related to the CoOSi bond vibrations 22 . In contrast, these CoO or CoOSi bands are not observed in Co/S‐1 catalyst.…”

Section: Resultsmentioning

confidence: 87%

In situ encapsulated subnanometric CoO clusters within silicalite‐1 zeolite for efficient propane dehydrogenation

Song

et al. 2021

AIChE Journal

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Cobalt‐based catalysts are promising alternatives to replace Pt‐ and Cr‐based catalysts for propane dehydrogenation (PDH). However, the sintering and reduction of unstable Co sites cause fast deactivation. Herein, the ultrasmall cobalt oxide clusters encapsulated within silicalite‐1 zeolites (CoO@S‐1) has been obtained via a ligand assistance in situ crystallization method. This CoO@S‐1 catalyst exhibits an attractive propylene formation rate of 13.66 mmolC3H6·gcat−1·h−1 with selectivity of >92% and is durable during 120‐h PDH reaction with five successive regeneration cycles. The high PDH activity of CoO@S‐1 is assigned to the encapsulated CoO clusters are favorable for propane adsorption and can better stabilize the detached H* species from propane, leading to the lower dehydrogenation barriers than framework Co2+ cations and Co3O4 nanoparticles. Additionally, the π‐binding propylene on CoO clusters can prevent the over‐dehydrogenation reaction compared with the di‐σ binding propylene on metallic Co, leading to the superior propylene selectivity and catalytic stability.

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“…Ce is less electronegative than Si and O, which invokes an electron‐rich center located around the SiO bond. [ 24 ] Electrostatic potential mapping by Li et al. [ 24 ] indicated that adding Ce to a SiOSi network can enhance electrons trapped on the oxygen vacancies, electron transfer and augment catalytic ozonation performance.…”

Section: Resultsmentioning

confidence: 99%

“…Ce is less electronegative than Si and O, which invokes an electron-rich center located around the SiO bond. [24] Electrostatic potential mapping by Li et al [24] indicated that adding Ce to a SiOSi network can enhance electrons trapped on the oxygen vacancies, electron transfer and augment catalytic ozonation performance. As a consequence of the defects in the CeOSi framework, a large amount of unpaired electrons gather around the metal atoms and free electron regions occur, particularly in the oxygen vacancy spaces.…”

Section: First Principles Calculationsmentioning

confidence: 99%

Engineering Multidefects on Ce_xSi₁₋_xO₂₋_δ Nanocomposites for the Catalytic Ozonation Reaction

Esmailpour

Horlyck

Kumar

et al. 2021

Small

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Herein, it is shown that by engineering defects on CexSi1−xO2−δ nanocomposites synthesized via flame spray pyrolysis, oxygen vacancies can be created with an increased density of trapped electrons, enhancing the formation of reactive oxygen species (ROSs) and hydroxyl radicals in an ozone‐filled environment. Spectroscopic analysis and density functional theory calculations indicate that two‐electron oxygen vacancies (OV0) or peroxide species, and their degree of clustering, play a critical role in forming reactive radicals. It is also found that a higher Si content in the binary oxide imposes a high OV0 ratio and, consequently, higher catalytic activity. Si inclusion in the nanocomposite appears to stabilize the surface oxygen vacancies as well as increase the reactive electron density at these sites. A mechanistic study on effective ROSs generated during catalytic ozonation reveals that the hydroxyl radical is the most effective ROS for organic degradation and is formed primarily through H2O2 generation in the presence of the OV0. Examining the binary oxides offers insights on the contribution of oxygen vacancies and their state of charge to catalytic reactions, in this instance for the catalytic ozonation of organic compounds.

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Composite Si-O-metal network catalysts with uneven electron distribution: Enhanced activity and electron transfer for catalytic ozonation of carbamazepine

Cited by 45 publications

References 51 publications

Sol-Gel Processed Cobalt-Doped Methylated Silica Membranes Calcined under N2 Atmosphere: Microstructure and Hydrogen Perm-Selectivity

Sol-Gel Processed Cobalt-Doped Methylated Silica Membranes Calcined under N2 Atmosphere: Microstructure and Hydrogen Perm-Selectivity

In situ encapsulated subnanometric CoO clusters within silicalite‐1 zeolite for efficient propane dehydrogenation

Engineering Multidefects on Ce_xSi₁₋_xO₂₋_δ Nanocomposites for the Catalytic Ozonation Reaction

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Composite Si-O-metal network catalysts with uneven electron distribution: Enhanced activity and electron transfer for catalytic ozonation of carbamazepine

Cited by 45 publications

References 51 publications

Sol-Gel Processed Cobalt-Doped Methylated Silica Membranes Calcined under N2 Atmosphere: Microstructure and Hydrogen Perm-Selectivity

Sol-Gel Processed Cobalt-Doped Methylated Silica Membranes Calcined under N2 Atmosphere: Microstructure and Hydrogen Perm-Selectivity

In situ encapsulated subnanometric CoO clusters within silicalite‐1 zeolite for efficient propane dehydrogenation

Engineering Multidefects on CexSi1−xO2−δ Nanocomposites for the Catalytic Ozonation Reaction

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Product

Resources

About

Engineering Multidefects on Ce_xSi₁₋_xO₂₋_δ Nanocomposites for the Catalytic Ozonation Reaction