Amorphous Fe2O3 improved [O] transfer cycle of Ce4+/Ce3+ in CeO2 for atom economy synthesis of imines at low temperature

Qin, Jiaheng; Long, Yu; Wu, Wei; Zhang, Wei; Gao, Zekun; Ma, Jiantai

doi:10.1016/j.jcat.2019.01.032

Cited by 63 publications

(36 citation statements)

References 63 publications

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“…This indicates that the majority of Fe species are doped into the near surface of CeO 2 . The Ce 3d spectrum of Fe−CeO 2 nanorods can be de‐convoluted into ten peaks related to Ce 3+ and Ce 4+ [14] . The results shows that The Ce cations in all samples are mainly in the Ce 4+ oxidation state and the surface concentration of Ce 3+ increase slightly from 25 % (pure CeO 2 ) to ∼30 % (Fe−CeO 2 ).…”

Section: Resultsmentioning

confidence: 95%

Novel Fe‐modified CeO₂ Nanorod Catalyst for the Dimethyl Carbonate Formation from CO₂ and Methanol

et al. 2022

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A series of Fe-modified CeO 2 catalysts with nanoparticle, nanorod, nanocube and nano-octahedron morphologies were synthesized and applied for direct synthesis of dimethyl carbonate (DMC) from CO 2 and methanol. The Fe-modification shows a remarkably promoting effect on the formation of DMC over Fe-modified CeO 2 nanorod. The DMC yield was improved from 0.202 to 2.568 mmol DMC per g cat by 2 %Fe-modification of CeO 2 nanorod. A synergistic effect among the moderate acidbasic sites, specific surface area and surface composition resulted from Fe-modification was proposed to be crucial to obtaining the high reactivity of DMC formation.

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Section: Resultsmentioning

confidence: 95%

Novel Fe‐modified CeO₂ Nanorod Catalyst for the Dimethyl Carbonate Formation from CO₂ and Methanol

et al. 2022

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“…Typically. this reaction proceeds through these two key steps [ 31 ] : i) the oxidation of benzyl alcohol to form benzaldehyde, ii) benzaldehyde reacts with aniline to produce imines. Notably, the step (ii) can occur even without any catalysts in toluene at 90 °C (Figure S20, Supporting Information).…”

Section: Resultsmentioning

confidence: 99%

Atomically Precise Single Metal Oxide Cluster Catalyst with Oxygen‐Controlled Activity

Guo

Chen

et al. 2022

Adv Funct Materials

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Single cluster catalysts (SCCs) consisting of atomically precise metal nanoclusters dispersed on supports represent a new frontier of heterogeneous catalysis. However, the ability to synthesize SCCs with high loading and to precisely introduce non‐metal atoms to further tune their catalytic activity and reaction scope of SCCs have been longstanding challenges. Here, a new interface confinement strategy is developed for the synthesis of a high density of atomically precise Ru oxide nanoclusters (Ru3O2) on reduced graphene oxide (rGO), attributed to the suppression of diffusion‐induced metal cluster aggregation. Ru3O2/rGO exhibits a significantly enhanced activity for oxidative dehydrogenation of 1,2,3,4‐tetrahydroquinoline (THQ) to quinoline with a high yield (≈86%) and selectivity (≈99%), superior to Ru and RuO2 nanoparticles, and homogeneous single/multiple‐site Ru catalysts. In addition, Ru3O2/rGO is also capable of efficiently catalyzing more complex oxidative reactions involving three reactants. The theoretical calculations reveal that the presence of two oxygen atoms in the Ru3O2 motif not only leads to a weak hydrogen bonding interaction between the THQ reactant and the active site, but also dramatically depletes the density of states near the Fermi level, which is attributed to the increased positive valence state of Ru and the enhanced oxidative activity of the Ru3O2 cluster for hydrogen abstraction.

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“…It has been reported earlier that CeO 2 can be used as an easily separable catalyst for imine synthesis at low temperature (<100°C) ( Zhang et al, 2017 ; Zhang et al, 2018 ; Chen et al, 2020 ; Wu et al, 2021 ) and oxygen vacancies (Ce 3+ defects) played an important role during this reaction. The Ce 3+ vacancies can promote the transition of benzyl alcohol to benzaldehyde, and the latter can easily couple with aniline to form an imine compound ( Tamura and Tomishige, 2015 ; Zhang et al, 2017 ; Qin et al, 2019 ). From the above-mentioned results, it can be seen that CeO 2 -H2 possessed the largest surface area (111.4 m 2 /g) and a relatively high Ce 3+ ratio (28.1%), which contributed to the highest imine reaction rate.…”

Section: Resultsmentioning

confidence: 99%

CeO2 Structure Adjustment by H2O via the Microwave–Ultrasonic Method and Its Application in Imine Catalysis

2022

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CeO2 with fusiform structures were prepared by the combined microwave–ultrasonic method, and their morphologies and surface structure were changed by simply adding different amounts of H2O (1–5 ml) to the precursor system. The addition of H2O changed the PVP micelle structure and the surface state, resulting in CeO2 with a different specific surface area (64–111 m2 g−1) and Ce3+ defects (16.5%–28.1%). The sample with 2 ml H2O exhibited a high surface area (111.3 m2∙g−1) and relatively more surface defects (Ce3+%: 28.1%), resulting in excellent catalytic activity (4.34 mmol g−1 h−1).

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Amorphous Fe2O3 improved [O] transfer cycle of Ce4+/Ce3+ in CeO2 for atom economy synthesis of imines at low temperature

Cited by 63 publications

References 63 publications

Novel Fe‐modified CeO₂ Nanorod Catalyst for the Dimethyl Carbonate Formation from CO₂ and Methanol

Novel Fe‐modified CeO₂ Nanorod Catalyst for the Dimethyl Carbonate Formation from CO₂ and Methanol

Atomically Precise Single Metal Oxide Cluster Catalyst with Oxygen‐Controlled Activity

CeO2 Structure Adjustment by H2O via the Microwave–Ultrasonic Method and Its Application in Imine Catalysis

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Amorphous Fe2O3 improved [O] transfer cycle of Ce4+/Ce3+ in CeO2 for atom economy synthesis of imines at low temperature

Cited by 63 publications

References 63 publications

Novel Fe‐modified CeO2 Nanorod Catalyst for the Dimethyl Carbonate Formation from CO2 and Methanol

Novel Fe‐modified CeO2 Nanorod Catalyst for the Dimethyl Carbonate Formation from CO2 and Methanol

Atomically Precise Single Metal Oxide Cluster Catalyst with Oxygen‐Controlled Activity

CeO2 Structure Adjustment by H2O via the Microwave–Ultrasonic Method and Its Application in Imine Catalysis

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Novel Fe‐modified CeO₂ Nanorod Catalyst for the Dimethyl Carbonate Formation from CO₂ and Methanol

Novel Fe‐modified CeO₂ Nanorod Catalyst for the Dimethyl Carbonate Formation from CO₂ and Methanol