Negative Thermal Expansion Occurs in a Bauxite-Based Aluminum Borate Ceramic Whisker with a Nanofiber Microstructure

Kenawy, Sayed H.; Hamzawy, Esmat M. A.

doi:10.1007/s11661-018-4739-4

Cited by 5 publications

(1 citation statement)

References 16 publications

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“…( Figure 2 a, middle). Subsequent analysis authenticated these peaks as indicative of Al 20 B 4 O 36 (JCPDS: 80-2300) [ 22 ]. Conversely, a broad peak within the 20–30° range was singularly displayed in the diffraction pattern of catalyst AlBOx-650, indicative of an amorphous state during the 650 °C calcination phase ( Figure S5 ).…”

Section: Resultsmentioning

confidence: 99%

Modulating Electron Density of Boron–Oxygen Groups in Borate via Metal Electronegativity for Propane Oxidative Dehydrogenation

Li,

Yao,

Chai

et al. 2024

Materials

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The robust electronegativity of the [BO3]3− structure enables the extraction of electrons from adjacent metals, offering a strategy for modulating oxygen activation in propane oxidative dehydrogenation. Metals (Ni 1.91, Al 1.5, and Ca 1.0) with varying electronegativities were employed to engineer borate catalysts. Metals in borate lacked intrinsic catalytic activity for propane conversion; instead, they modulated [BO3]3− group reactivity through adjustments in electron density. Moderate metal electronegativity favored propane oxidative dehydrogenation to propylene, whereas excessively low electronegativity led to propane overoxidation to carbon dioxide. Aluminum, with moderate electronegativity, demonstrated optimal performance. Catalyst AlBOx-1000 achieved a propane conversion of 47.5%, with the highest propylene yield of 30.89% at 550 °C, and a total olefin yield of 51.51% with a 58.92% propane conversion at 575 °C. Furthermore, the stable borate structure prevents boron element loss in harsh conditions and holds promise for industrial-scale catalysis.

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Section: Resultsmentioning

confidence: 99%