What are the preferred CeO2 exposed planes for the synthesis of dimethyl carbonate? Answers from theory and experiments

Marciniak, Aryane A.; Henrique, Fábio J.F.S.; Lima, Adriana F.F. de; Alves, Odivaldo C.; Moreira, Carla R.; Appel, Lucia G.; Mota, Cláudio J. A.

doi:10.1016/j.mcat.2020.111053

Cited by 20 publications

(25 citation statements)

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“…In addition, the bands appeared around 1027 and 1592 cm −1 are the characteristic of -(CO 3 ) from bidentate carbonate [36,37,39]. The bands at 1453 and 1598 cm −1 are assigned for stretching frequencies of hydrogen carbonate whereas 1104, 1350 and 1453 cm −1 correspond to -(CO 3 ) group of MMC [38][39][40]. Formation of DMC is the final step by the reaction of activated methanol and methyl carbonate group.…”

Section: Reaction Mechanism Study Using Ftir Methodsmentioning

confidence: 98%

Direct Dimethyl Carbonates Synthesis over CeO2 and Evaluation of Catalyst Morphology Role in Catalytic Performance

et al. 2021

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In recent years, direct synthesis of dimethyl carbonate (DMC) from carbon dioxide (CO2) has received considerable attention due to green and sustainable technology. Here, we report a production of DMC from major greenhouse gases and CO2 using various morphologies of cerium oxide (CeO2). Time-dependent synthesis of CeO2, with controlled morphology having various shapes including sphere, nanorods and spindle shape, along with its formation mechanism is proposed. The experimental results indicate the morphology of CeO2 was mostly dependent on the reaction time where crystal growth occurred through Ostwald ripening. The morphology, size and shape of CeO2 were observed using transmission electron microscopy (TEM) and field emission scanning electron microscopy (FESEM).The crystallographic analysis using X-ray diffraction (XRD) shows cubic fluorite phase of CeO2 with crystallite size ~72.0 nm using the Debye–Scherrer equation. The nitrogen adsorption desorption technique suggested the formation of the highly mesoporous framework of CeO2 and the excellent surface area around 104.5 m2/g obtained for CeO2 spindles by Brunauer–Emmett–Teller (BET) method. The DMC synthesis reactions were studied over CeO2 catalyst with different morphologies. The results of catalytic reactions specify that the morphology of catalyst plays an important role in their catalytic performances, where spindle shape CeO2 was the most active catalyst producing of up to13.04 mmol of DMC. Furthermore, various dehydrating agents were used to improve the DMC production at optimized reaction parameters. The overall results reveal that the higher surface area and spindle shape of CeO2 makes it a useful, reusable catalyst for one-pot DMC synthesis.

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Section: Reaction Mechanism Study Using Ftir Methodsmentioning

confidence: 98%

Direct Dimethyl Carbonates Synthesis over CeO2 and Evaluation of Catalyst Morphology Role in Catalytic Performance

et al. 2021

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“…Urakawa et al reported the continuous DMC synthesis from CO 2 and methanol over CeO 2 + 2-cyanopyridine system, which exhibited outstanding methanol conversion of >95% and >99% selectivity toward dimethyl carbonate with much shorter reaction time in a continuous flow fixed-bed reactor than in batch operation . Later, the continuous synthesis of DMC from CO 2 and methanol with excellent yields in a fixed bed has been widely adopted via optimizing the catalyst composition and morphology, the catalyst amount, CO 2 pressure, reaction temperature, and residence time. ,, Concerning catalyst composition and morphology, it has been reported that the adsorption and activation of CO 2 for the synthesis of DMC is significantly affected by the surface oxygen vacancy sites and acid–base properties of the catalysts. , As a result, several strategies have been adopted to increase the number of surface oxygen vacancy sites and acid–base sites of CeO 2 -based catalysts for the synthesis of DMC via tuning the morphology, structure and composition, such as Ti x Ce 1– x O 2 nanocomposites, , surface modification of CeO 2 by rare earth metal, Zr-doped CeO 2 nanorods, MgO-CeO 2 , CeO 2 nanomaterials with differently exposed planes . For example, Urakawa et al reported that the addition of rare earth metals (La, Gd, and Pr) can effectively enhance the catalyst stability by improving the methoxy species adsorption strength while preventing the adsorption of 2-picolinamide-like species, as shown in Figure c .…”

Section: Organic Synthesis Using Co2 As a Carbon Feedstockmentioning

confidence: 99%

“…308,309 As a result, several strategies have been adopted to increase the number of surface oxygen vacancy sites and acid−base sites of CeO 2 -based catalysts for the synthesis of DMC via tuning the morphology, structure and composition, such as Ti x Ce 1−x O 2 nanocomposites, 306,310 surface modification of CeO 2 by rare earth metal, 307 Zr-doped CeO 2 nanorods, 311 MgO-CeO 2 , 312 CeO 2 nanomaterials with differently exposed planes. 313 For example, Urakawa et al reported that the addition of rare earth metals (La, Gd, and Pr) can effectively enhance the catalyst stability by improving the methoxy species adsorption strength while preventing the adsorption of 2-picolinamide-like species, as shown in Figure 27c. 307 Compared with pure CeO 2 , doping metals such as Zr, Zn, or Ti into CeO 2 enhances the catalytic activity via increasing oxygen vacancy concentration and promoting the surface acid−base sites, 306,311,314 whereas the CeO 2 nanorods doped with NiO, CuO, and CoO or CaO showed a worse catalytic activity than pure CeO 2 nanorods with the (110)dominated surface structures.…”

Section: Organic Synthesis Using Co 2 As a Carbon Feedstockmentioning

confidence: 99%

Ceria-Based Materials for Thermocatalytic and Photocatalytic Organic Synthesis

et al. 2021

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Value-added chemicals, fuels, and pharmaceuticals synthesized by organic transformation from raw materials via catalytic techniques have attracted enormous attention in the past few decades. Heterogeneous catalysts with high stability, long cycling life, good environmental-friendliness, and economic efficiency are greatly desired to accomplish the catalytic organic transformations. With the advantages of reversible Ce3+/Ce4+ redox pairs, tailorable oxygen vacancies, and surface acid–base properties, ceria-based catalysts have been actively investigated in the fields of catalytic organic synthesis. In this Review, we summarize the fundamentals and latest applications of ceria-based heterogeneous catalysts for organic transformations via thermocatalytic and photocatalytic routes. The fabricating approaches of various ceria and ceria-based catalysts and their structure/composition–activity relationship are discussed and prospected. The advanced characterization techniques and theoretical methods for reaction mechanism studies over CeO2-based catalysts are summarized and discussed. This comprehensive Review provides a basic understanding of the structure–performance relationships of ceria-based catalysts for organic synthesis. In addition, it also provides some insights and outlooks in the design and research direction in the ceria-based catalysts with better performance.

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“…Therefore, efficient catalyst synthesis and detailed activity mechanism research are still very important. As a cheap and highly active rare earth metal oxide, CeO 2 has attracted extensive attention in the study of the synthesis of CO 2 and methanol into DMC. − A large number of oxygen vacancies and acid-base sites within CeO 2 promote the adsorption and activation of carbon dioxide, showing good catalytic activity and selectivity . The morphology of CeO 2 will greatly affect the exposed crystal surface and the number of oxygen vacancies on the surface of the catalyst, and these two factors are quite important in determining the performance of the catalyst. − …”

Section: Introductionmentioning

confidence: 99%

Study of Direct Synthesis of DMC from CO₂ and Methanol on CeO₂: Theoretical Calculation and Experiment

Zhu

Liu

Yong

et al. 2022

Ind. Eng. Chem. Res.

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Rare earth metal oxides are known to have good catalytic effectiveness in the direct synthesis of dimethyl carbonate (DMC) from CO2 and methanol. In this work, we screened ceria (CeO2) catalysts by analyzing their capacity for CO2 adsorption. The effects of the crystal surface morphology and oxygen vacancy on the catalytic performance of the ceria catalyst were studied by using density functional theory (DFT). The results show that the (110) surface and higher oxygen vacancy content can better promote the synthesis of DMC and that the rod-shaped CeO2 catalyst has a better catalytic effect. The oxygen vacancy content on the catalyst was improved by freeze-drying and confirmed by thermogravimetric analysis, Raman spectroscopy, and electron paramagnetic resonance. The freeze-dried CeO2 (CeO2-FD) then showed a higher catalytic performance. The conversion rate of methanol and the yield of DMC were 33.95% and 584 mmol g–1cat, respectively, under mild conditions (140 °C and 1 MPa).

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What are the preferred CeO2 exposed planes for the synthesis of dimethyl carbonate? Answers from theory and experiments

Cited by 20 publications

References 47 publications

Direct Dimethyl Carbonates Synthesis over CeO2 and Evaluation of Catalyst Morphology Role in Catalytic Performance

Direct Dimethyl Carbonates Synthesis over CeO2 and Evaluation of Catalyst Morphology Role in Catalytic Performance

Ceria-Based Materials for Thermocatalytic and Photocatalytic Organic Synthesis

Study of Direct Synthesis of DMC from CO₂ and Methanol on CeO₂: Theoretical Calculation and Experiment

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What are the preferred CeO2 exposed planes for the synthesis of dimethyl carbonate? Answers from theory and experiments

Cited by 20 publications

References 47 publications

Direct Dimethyl Carbonates Synthesis over CeO2 and Evaluation of Catalyst Morphology Role in Catalytic Performance

Direct Dimethyl Carbonates Synthesis over CeO2 and Evaluation of Catalyst Morphology Role in Catalytic Performance

Ceria-Based Materials for Thermocatalytic and Photocatalytic Organic Synthesis

Study of Direct Synthesis of DMC from CO2 and Methanol on CeO2: Theoretical Calculation and Experiment

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Study of Direct Synthesis of DMC from CO₂ and Methanol on CeO₂: Theoretical Calculation and Experiment