XPS Study on Calcining Mixtures of Brucite with Titania

Sánchez-Zambrano, Karla Sofía; Hernández-Reséndiz, Marina; Gómez-Rodríguez, Cristian; García-Quiñonez, Linda Viviana; Aguilar-Martínez, J.A.; Rodríguez-Castellanos, Edén Amaral; González, Luis Felipe Verdeja; González, Daniel Fernández; Castillo-Rodríguez, Guadalupe Alan

doi:10.3390/ma15093117

Cited by 25 publications

(6 citation statements)

References 27 publications

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“…These suboxides (like AlOₓ) have lower binding energies compared to fully oxidized Al 2 O 3 , creating a distinctive shoulder at lower binding energies in the spectrum. Similar tendencies were observed by other authors analyzing oxide-based compounds [ 64 , 65 , 66 , 67 ]. The Al 2p chemical bond analysis of Al nanoparticles ( Figure 6 b) disclosed the existence of the Al 3+ component only at 74.2 eV binding energy, representing an Al 2 O 3 chemical compound.…”

Section: Resultssupporting

confidence: 89%

Enhanced Hydrogen Generation through Low-Temperature Plasma Treatment of Waste Aluminum for Hydrolysis Reaction

Urbonavicius,

Varnagiris,

Knoks

et al. 2024

Materials

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This study investigates the low-temperature hydrogen plasma treatment approach for the improvement of hydrogen generation through waste aluminum (Al) reactions with water and electricity generation via proton-exchange membrane fuel cell (PEM FC). Waste Al scraps were subjected to ball milling and treated using two different low-temperature plasma regimes: Diode and magnetron-initiated plasma treatment. Hydrolysis experiments were conducted using powders with different treatments, varying molarities, and reaction temperatures to assess hydrogen generation, reaction kinetics, and activation energy. The results indicate that magnetron-initiated plasma treatment significantly enhances the hydrolysis reaction kinetics compared to untreated powders or those treated with diode-generated plasma. Analysis of chemical bonds revealed that magnetron-initiated hydrogen plasma treatment takes advantage by promoting a dual procedure: Surface cleaning and Al nanocluster deposition on top of Al powders. Moreover, it was modeled that such H2 plasma could penetrate up to 150 Å depth. Meanwhile, electricity generation tests demonstrate that only 0.2 g of treated Al powder can generate approximately 1 V for over 300 s under a constant 2.5 Ω load and 1.5 V for 2700 s with a spinning fan.

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Section: Resultssupporting

confidence: 89%

Enhanced Hydrogen Generation through Low-Temperature Plasma Treatment of Waste Aluminum for Hydrolysis Reaction

Urbonavicius,

Varnagiris,

Knoks

et al. 2024

Materials

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“…However, in the second stage, the greater losses can be explained by the more significant presence of Mg(OH) 2 (brucite) which is decomposed to periclase MgO as the most stable form. Furthermore, the DTG curves exhibit the maximum weight losses at around 300–480 °C, consistent with the TGA curves . For fresh and spent catalysts, approximately 2.5 and 5% of losses were observed for stage 1, 17.5 and 23% for stage 2, and only 1% for stage 3, respectively.…”

Section: Resultssupporting

confidence: 81%

“…Furthermore, the DTG curves exhibit the maximum weight losses at around 300−480 °C, consistent with the TGA curves. 81 For fresh and spent catalysts, approximately 2.5 and 5% of losses were observed for stage 1, 17.5 and 23% for stage 2, and only 1% for stage 3, respectively.…”

Section: R3mentioning

confidence: 89%

Versatile Heterogeneous Catalytic System for the Selective Synthesis of Limonene Epoxide and Diepoxide

Gallego-Villada,

Alarcón,

Villa

2023

Ind. Eng. Chem. Res.

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The products obtained from limonene epoxidation can be used as intermediates or precursors in organic and pharmaceutical synthesis. Commercial magnesium oxide was evaluated as a heterogeneous catalyst in the epoxidation of R-(+)-limonene using H 2 O 2 in a Payne reaction system, using acetonitrile as an oxidant activator and water and acetone as solvents. The effect of temperature and the concentration of catalyst, H 2 O 2, and limonene were evaluated; the highest yields for limonene epoxide (80%) and diepoxide (96%) were found at 50 °C and 30 min and 2 h, respectively. Fresh and spent catalysts were characterized by X-ray diffraction, thermogravimetric analysis, N 2 adsorption−desorption isotherms, Fourier transform-infrared, and scanning electron microscopy-energy dispersive X-ray. The efficiency of H 2 O 2 in the epoxidation reaction varied between 100 and 20% in the time range of 0−30 min for all tested reaction conditions. The production of peroxyacetimidic acid as an intermediate oxidant in the limonene epoxide synthesis was described using a pseudohomogeneous reversible model (E = 58.61 kJ mol −1 ), while the heterogeneous model describes both the decomposition of H 2 O 2 (E = 29.06 kJ mol −1 ) and the epoxidation of limonene with the intermediate (E = 52.28 kJ mol −1 ). Leaching tests verified the heterogeneity of MgO which was used in four consecutive cycles.

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“…The Ti 4+ XPS spectrum peaks at around 458.9 and 464.7 eV, respectively, corresponding to the Ti 2p 3/2 and Ti 2p 1/2 spin–orbit doublets. These values are similar to those reported for fully oxidized titanium, but the peak separation was slightly larger (∼5.8 eV) than that of pure Ti 4+ films (∼5.54 eV) due to the presence of Ti 3+ states . The Ti 3+ peaks at 456.6 and 462.6 eV.…”

supporting

confidence: 86%

Comment on “Bipolar Resistive Switching in Lanthanum Titanium Oxide and an Increased On/Off Ratio Using an Oxygen-Deficient ZnO Interlayer”

Wong

2024

ACS Appl. Mater. Interfaces

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The Mott-based resistive switching random access memory (RRAM) has been considered as a promising candidate for next-generation nonvolatile mass storage. Its performance relies on the oxygen migration process. In ACS Appl. Mater. Interfaces 2022, 14, 17682−17690, Wang et al. demonstrated that inserting a ZnO layer between the top tungsten electrode and the lanthanum titanium oxide (LTO) layer can improve the ON/OFF current ratio of the RRAM. This improvement was attributed to the increased oxygen vacancies in the ZnO layer. We argue their interpretation with the role, significance, and statistics of the oxygen vacancy in the samples. Our experimental evidence contradicts their claim, and we propose that hydroxy groups should be the responsible candidate for their claimed oxygen vacancy peak at around 531−532 eV in the O 1s photoelectron spectroscopy observed in their samples. We thus propose an alternative mechanism for the ON/OFF ratio enhancement with the ZnO interlayer: the ZnO layer prevents the LTO oxygen and hydroxy groups migration and from reacting with the multivalent tungsten electrode.

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XPS Study on Calcining Mixtures of Brucite with Titania

Cited by 25 publications

References 27 publications

Enhanced Hydrogen Generation through Low-Temperature Plasma Treatment of Waste Aluminum for Hydrolysis Reaction

Enhanced Hydrogen Generation through Low-Temperature Plasma Treatment of Waste Aluminum for Hydrolysis Reaction

Versatile Heterogeneous Catalytic System for the Selective Synthesis of Limonene Epoxide and Diepoxide

Comment on “Bipolar Resistive Switching in Lanthanum Titanium Oxide and an Increased On/Off Ratio Using an Oxygen-Deficient ZnO Interlayer”

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