Morphology Controlled Synthesis of γ-Al<sub>2</sub>O<sub>3</sub> Nano-Crystallites in Al@Al<sub>2</sub>O<sub>3</sub> Core–Shell Micro-Architectures by Interfacial Hydrothermal Reactions of Al Metal Substrates
Fine control of morphology and exposed crystal facets of porous γ-Al<sub>2</sub>O<sub>3</sub> is of significant importance in many application areas such as functional nanomaterials and heterogeneous catalysts. Herein, a morphology controlled in situ synthesis of Al@Al<sub...
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MDPI AG
2021-01-01
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| Series: | Nanomaterials |
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| Online Access: | https://www.mdpi.com/2079-4991/11/2/310 |
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| author | Dohyeon Han Doohwan Lee |
| author_facet | Dohyeon Han Doohwan Lee |
| author_sort | Dohyeon Han |
| collection | DOAJ |
| description | Fine control of morphology and exposed crystal facets of porous γ-Al<sub>2</sub>O<sub>3</sub> is of significant importance in many application areas such as functional nanomaterials and heterogeneous catalysts. Herein, a morphology controlled in situ synthesis of Al@Al<sub>2</sub>O<sub>3</sub> core–shell architecture consisting of an Al metal core and a porous γ-Al<sub>2</sub>O<sub>3</sub> shell is explored based on interfacial hydrothermal reactions of an Al metal substrate in aqueous solutions of inorganic anions. It was found that the morphology and structure of boehmite (γ-AlOOH) nano-crystallites grown at the Al-metal/solution interface exhibit significant dependence on temperature, type of inorganic anions (Cl<sup>−</sup>, NO<sub>3</sub><sup>−</sup>, and SO<sub>4</sub><sup>2−</sup>), and acid–base environment of the synthesis solution. Different extents of the electrostatic interactions between the protonated hydroxyl groups on (010) and (001) facets of γ-AlOOH and the inorganic anions (Cl<sup>−</sup>, NO<sub>3</sub><sup>−</sup>, SO<sub>4</sub><sup>2−</sup>) appear to result in the preferential growth of γ-AlOOH toward specific crystallographic directions due to the selective capping of the facets by adsorption of the anions. It is hypothesized that the unique Al@Al<sub>2</sub>O<sub>3</sub> core–shell architecture with controlled morphology and exposed crystal-facets of the γ-Al<sub>2</sub>O<sub>3</sub> shell can provide significant intrinsic catalytic properties with enhanced heat and mass transport to heterogeneous catalysts for applications in many thermochemical reaction processes. The direct fabrication of γ-Al<sub>2</sub>O<sub>3</sub> nano-crystallites from Al metal substrate with in-situ modulation of their morphologies and structures into 1D, 2D, and 3D nano-architectures explored in this work is unique and can offer significant opportunities over the conventional methods. |
| first_indexed | 2024-03-09T03:41:52Z |
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| institution | Directory Open Access Journal |
| issn | 2079-4991 |
| language | English |
| last_indexed | 2024-03-09T03:41:52Z |
| publishDate | 2021-01-01 |
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| series | Nanomaterials |
| spelling | doaj.art-d0cb7e91ba2f487580a30fb7ea5284972023-12-03T14:40:18ZengMDPI AGNanomaterials2079-49912021-01-0111231010.3390/nano11020310Morphology Controlled Synthesis of γ-Al<sub>2</sub>O<sub>3</sub> Nano-Crystallites in Al@Al<sub>2</sub>O<sub>3</sub> Core–Shell Micro-Architectures by Interfacial Hydrothermal Reactions of Al Metal SubstratesDohyeon Han0Doohwan Lee1Department of Chemical Engineering, The University of Seoul, Dongdaemun-gu, Seoulsiripdaero 163, Seoul 02504, KoreaDepartment of Chemical Engineering, The University of Seoul, Dongdaemun-gu, Seoulsiripdaero 163, Seoul 02504, KoreaFine control of morphology and exposed crystal facets of porous γ-Al<sub>2</sub>O<sub>3</sub> is of significant importance in many application areas such as functional nanomaterials and heterogeneous catalysts. Herein, a morphology controlled in situ synthesis of Al@Al<sub>2</sub>O<sub>3</sub> core–shell architecture consisting of an Al metal core and a porous γ-Al<sub>2</sub>O<sub>3</sub> shell is explored based on interfacial hydrothermal reactions of an Al metal substrate in aqueous solutions of inorganic anions. It was found that the morphology and structure of boehmite (γ-AlOOH) nano-crystallites grown at the Al-metal/solution interface exhibit significant dependence on temperature, type of inorganic anions (Cl<sup>−</sup>, NO<sub>3</sub><sup>−</sup>, and SO<sub>4</sub><sup>2−</sup>), and acid–base environment of the synthesis solution. Different extents of the electrostatic interactions between the protonated hydroxyl groups on (010) and (001) facets of γ-AlOOH and the inorganic anions (Cl<sup>−</sup>, NO<sub>3</sub><sup>−</sup>, SO<sub>4</sub><sup>2−</sup>) appear to result in the preferential growth of γ-AlOOH toward specific crystallographic directions due to the selective capping of the facets by adsorption of the anions. It is hypothesized that the unique Al@Al<sub>2</sub>O<sub>3</sub> core–shell architecture with controlled morphology and exposed crystal-facets of the γ-Al<sub>2</sub>O<sub>3</sub> shell can provide significant intrinsic catalytic properties with enhanced heat and mass transport to heterogeneous catalysts for applications in many thermochemical reaction processes. The direct fabrication of γ-Al<sub>2</sub>O<sub>3</sub> nano-crystallites from Al metal substrate with in-situ modulation of their morphologies and structures into 1D, 2D, and 3D nano-architectures explored in this work is unique and can offer significant opportunities over the conventional methods.https://www.mdpi.com/2079-4991/11/2/310boehmitealuminamorphology controlhydrothermal synthesiscore–shell structureheterogeneous catalysts |
| spellingShingle | Dohyeon Han Doohwan Lee Morphology Controlled Synthesis of γ-Al<sub>2</sub>O<sub>3</sub> Nano-Crystallites in Al@Al<sub>2</sub>O<sub>3</sub> Core–Shell Micro-Architectures by Interfacial Hydrothermal Reactions of Al Metal Substrates Nanomaterials boehmite alumina morphology control hydrothermal synthesis core–shell structure heterogeneous catalysts |
| title | Morphology Controlled Synthesis of γ-Al<sub>2</sub>O<sub>3</sub> Nano-Crystallites in Al@Al<sub>2</sub>O<sub>3</sub> Core–Shell Micro-Architectures by Interfacial Hydrothermal Reactions of Al Metal Substrates |
| title_full | Morphology Controlled Synthesis of γ-Al<sub>2</sub>O<sub>3</sub> Nano-Crystallites in Al@Al<sub>2</sub>O<sub>3</sub> Core–Shell Micro-Architectures by Interfacial Hydrothermal Reactions of Al Metal Substrates |
| title_fullStr | Morphology Controlled Synthesis of γ-Al<sub>2</sub>O<sub>3</sub> Nano-Crystallites in Al@Al<sub>2</sub>O<sub>3</sub> Core–Shell Micro-Architectures by Interfacial Hydrothermal Reactions of Al Metal Substrates |
| title_full_unstemmed | Morphology Controlled Synthesis of γ-Al<sub>2</sub>O<sub>3</sub> Nano-Crystallites in Al@Al<sub>2</sub>O<sub>3</sub> Core–Shell Micro-Architectures by Interfacial Hydrothermal Reactions of Al Metal Substrates |
| title_short | Morphology Controlled Synthesis of γ-Al<sub>2</sub>O<sub>3</sub> Nano-Crystallites in Al@Al<sub>2</sub>O<sub>3</sub> Core–Shell Micro-Architectures by Interfacial Hydrothermal Reactions of Al Metal Substrates |
| title_sort | morphology controlled synthesis of γ al sub 2 sub o sub 3 sub nano crystallites in al al sub 2 sub o sub 3 sub core shell micro architectures by interfacial hydrothermal reactions of al metal substrates |
| topic | boehmite alumina morphology control hydrothermal synthesis core–shell structure heterogeneous catalysts |
| url | https://www.mdpi.com/2079-4991/11/2/310 |
| work_keys_str_mv | AT dohyeonhan morphologycontrolledsynthesisofgalsub2subosub3subnanocrystallitesinalalsub2subosub3subcoreshellmicroarchitecturesbyinterfacialhydrothermalreactionsofalmetalsubstrates AT doohwanlee morphologycontrolledsynthesisofgalsub2subosub3subnanocrystallitesinalalsub2subosub3subcoreshellmicroarchitecturesbyinterfacialhydrothermalreactionsofalmetalsubstrates |