Oxygen-vacancy generation in MgFe2O4 by high temperature calcination and its improved photocatalytic activity for CO2 reduction

Fu, Liming; Chen, Haowen; Wang, Kang; Wang, Xitao

doi:10.1016/j.jallcom.2021.161925

Cited by 48 publications

(30 citation statements)

References 47 publications

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“…It is noteworthy that the light absorption increased with the decrease in the stoichiometric ratio of La. It is known from the literature that enhanced light absorption is due to the presence of higher oxygen vacancies and defective lattice structure [54–56]. In this regard, it can be concluded that La 0.5 Fe 1.5 O 3 and Fe 3 O 4 NPs have the most oxygen vacancies and structural defects.…”

Section: Resultsmentioning

confidence: 82%

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Combustion and secondary atomization behavior of nanofuel droplets laden with hematite, magnetite and lanthanum orthoferrites nanoparticles**

Küçükosman,

Alper Yontar,

Gökhan Ünlü

et al. 2023

Propellants Explo Pyrotec

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Current research concerns the droplet combustion behavior of gasoline‐based nanofuel droplets containing hematite (Fe2O3), magnetite (Fe3O4) and lanthanum orthoferrites (LaFeO3, La0.5Fe1.5O3 and La0.75Fe1.25O3) perovskite type nanoparticles (NPs) at 2.5 % wt. particle loadings. The results showed that the size distribution of hematite and magnetite NPs is on the 90–100 nm scale, while the lanthanum orthoferrites NPs have a particle size distribution of 25–40 nm. The particles with the largest surface area (78,5098 m2/g) and enhanced oxygen adsorbing ability were La0.5Fe1.5O3 NPs. Droplet combustion experiments were recorded with a high speed camera and a 7.5–14 μm spectral area thermal camera. Fe3O4 and LaFeO3 NPs high agglomerate tendency allowed only a single microexplosion event in nanofuel droplets towards the end of the experiment. Only the G/La0.5Fe1.5O3 fuel droplets trended to obey the D2‐law. Nanofuel droplets containing La0.5Fe1.5O3 NPs exhibited the highest maximum flame temperature of 264 °C. The catalytic activity of lanthanum orthoferrite perovskite‐type NPs during combustion was improved due to the decrease in the La ratio in the A‐site and the increase in the Fe ratio in the B‐site.

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Section: Resultsmentioning

confidence: 82%

“…In this regard, it can be concluded that La 0.5 Fe 1.5 O 3 and Fe 3 O 4 NPs have the most oxygen vacancies and structural defects. This can be attributed to the calcination process carried out at a high temperature of 600 °C in the last step of the production stage [54,55,57].…”

Section: Characterization Of Hematite Magnetite and Lanthanum Orthofe...mentioning

confidence: 99%

Combustion and secondary atomization behavior of nanofuel droplets laden with hematite, magnetite and lanthanum orthoferrites nanoparticles**

Küçükosman,

Alper Yontar,

Gökhan Ünlü

et al. 2023

Propellants Explo Pyrotec

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“…Furthermore, the surface valence state for the as-calcined, reduced, and regenerated samples is detected by XPS (Figure ). For all the as-synthesized materials, the characteristic peaks of Fe 2p 3/2 and Fe 2p 1/2 are observed at around 712 and 726 eV, respectively, which are larger than those of pure iron oxide . This difference is likely the electronic interaction between iron and other metals (Mg and Al).…”

Section: Resultsmentioning

confidence: 90%

Crystallite Phase Effect on the Redox Reactivity of Layered Double Hydroxide-Derived Iron-Based Oxygen Carriers for Chemical Looping CO₂ Reduction

Yihan

Jin

Guo

et al. 2023

ACS Sustainable Chem. Eng.

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Layered double hydroxide (LDH) is an effective self-template to develop efficient iron-based oxygen carriers for chemical looping CO 2 reduction. However, how the synthesis condition and metal ratio affect crystallite phase formation and redox reactivity is still unclear. In this work, a series of iron-based oxygen carriers are synthesized from thermal transformation of LDHs with varying metal ratios and calcination temperatures to reveal the crystallite phase formation mechanism and interpret the phase−activity relationship. Spinel MgAl δ Fe 2−δ O 4 is formed below 800 °C, while MgFe δ Al 2−δ O 4 is transformed into MgAl δ Fe 2−δ O 4 with increasing iron content at 800 °C. During H 2 −CO 2 redox cycles, Fe 3+ /Fe 2+ transition and iron segregation are observed for MgAl δ Fe 2−δ O 4 , but only the former occurs for MgFe δ Al 2−δ O 4 . For a phase mixture, with a low MgAl δ Fe 2−δ O 4 amount, Al migrates and substitutes Fe with the reincorporation of segregated iron to generate MgFe δ Al 2−δ O 4 . MgAl δ Fe 2−δ O 4 achieves higher oxygen storage capacity and weaker stability than MgFe δ Al 2−δ O 4 because the former favors the creation of more oxygen vacancies and induce a larger crystallite size. Due to the crystallite phase effect, Fe 0.5 Mg 2 Al 0.5 exhibits highest redox rates (6 mol [O] •kg Fe −1 •min −1 and 10 mol [O] •kg Fe −1•min −1 for the release and uptake of oxygen, respectively) and CO space-time yield (0.46 mol CO •kg Fe −1 •s −1 ). These findings provide a new route to tailor efficient oxygen carriers for chemical looping applications.

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“…The possible mechanism was that the increase of temperature might cause a carbon-mediated local reduction reaction at the surface of CuO/C, bringing an improvement in oxygen vacancies without disrupting the lattice. However, excessive temperature would lead to the structure collapse to reduce the oxygen-vacancy [ 29 ]. The experiment showed that with the increase of temperature (from 350 to 400 °C), oxygen dissociation is caused, leading to the generation of more oxygen vacancy.…”

Section: Resultsmentioning

confidence: 99%

MOF derived core-shell CuO/C with temperature-controlled oxygen-vacancy for real time analysis of glucose

et al. 2022

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Introducing oxygen-vacancy into the surface of the non-enzymatic sensor is supposed to be an effective way to improve inherently low catalytic activity and specificity of non-enzymatic sensors. In this work, CuO/C was synthesized at different temperatures using metal-organic frameworks as sacrificial templates to receive additional content of oxygen-vacancy. The product with the highest oxygen vacancy was found at 400 °C (named CuO/C-400 °C), which increased catalytically active sites and enhanced the charge-transfer efficiency. The sensing performance was afterward explored by amperometry under an optimal applied potential at 0.5 V (vs. SCE), presenting a broad detection range from 5.0 µM to 25.325 mM (R2 = 0.9998) with a sensitivity of 244.71 µA mM− 1 cm− 2, and a detection limit of 1 µM. Furthermore, the reliability and selectivity of CuO/C-400 °C sensors were extensively explored in the presence of artificial serum/saliva samples with gradient glucose concentrations. The human blood samples were also detected with high recoveries compared with the clinical Hexokinase method. Hence, the prepared CuO/C-400 °C sensor with a broad detection range and high selectivity can be applied for the diabetes diagnosis ex vivo without further dilution for real-time analysis in practical applications.

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Oxygen-vacancy generation in MgFe2O4 by high temperature calcination and its improved photocatalytic activity for CO2 reduction

Cited by 48 publications

References 47 publications

Combustion and secondary atomization behavior of nanofuel droplets laden with hematite, magnetite and lanthanum orthoferrites nanoparticles**

Combustion and secondary atomization behavior of nanofuel droplets laden with hematite, magnetite and lanthanum orthoferrites nanoparticles**

Crystallite Phase Effect on the Redox Reactivity of Layered Double Hydroxide-Derived Iron-Based Oxygen Carriers for Chemical Looping CO₂ Reduction

MOF derived core-shell CuO/C with temperature-controlled oxygen-vacancy for real time analysis of glucose

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Oxygen-vacancy generation in MgFe2O4 by high temperature calcination and its improved photocatalytic activity for CO2 reduction

Cited by 48 publications

References 47 publications

Combustion and secondary atomization behavior of nanofuel droplets laden with hematite, magnetite and lanthanum orthoferrites nanoparticles**

Combustion and secondary atomization behavior of nanofuel droplets laden with hematite, magnetite and lanthanum orthoferrites nanoparticles**

Crystallite Phase Effect on the Redox Reactivity of Layered Double Hydroxide-Derived Iron-Based Oxygen Carriers for Chemical Looping CO2 Reduction

MOF derived core-shell CuO/C with temperature-controlled oxygen-vacancy for real time analysis of glucose

Contact Info

Product

Resources

About

Crystallite Phase Effect on the Redox Reactivity of Layered Double Hydroxide-Derived Iron-Based Oxygen Carriers for Chemical Looping CO₂ Reduction