Novel Materials through Non-Hydrolytic Sol-Gel Processing: Negative Thermal Expansion Oxides and Beyond

Lind, Cora; Gates, Stacy D.; Pedoussaut, Nathalie M.; Baiz, Tamam I.

doi:10.3390/ma3042567

Cited by 39 publications

(21 citation statements)

References 122 publications

(169 reference statements)

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“…One of their research topics is the synthesis of crystalline ternary and quaternary metal oxides with A 2 M 3 O 12 stoichiometry (A = Al, Sc, Fe, In, Ga, Y, Mg-Zr, Mg-Hf, etc. ; M = Mo or W) that exhibit negative thermal expansion (NTE) [62][63][64][65]188,189]. The intrinsic advantage of NHSG chemistry-a high homogeneity of element mixing was fully exploited for NTE materials preparation.…”

Section: New Compositionsmentioning

confidence: 99%

The Power of Non-Hydrolytic Sol-Gel Chemistry: A Review

et al. 2017

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This review is devoted to non-hydrolytic sol-gel chemistry. During the last 25 years, non-hydrolytic sol-gel (NHSG) techniques were found to be attractive and versatile methods for the preparation of oxide materials. Compared to conventional hydrolytic approaches, the NHSG route allows reaction control at the atomic scale resulting in homogeneous and well defined products. Due to these features and the ability to design specific materials, the products of NHSG reactions have been used in many fields of application. The aim of this review is to present an overview of NHSG research in recent years with an emphasis on the syntheses of mixed oxides, silicates and phosphates. The first part of the review highlights well known condensation reactions with some deeper insights into their mechanism and also presents novel condensation reactions established in NHSG chemistry in recent years. In the second section we discuss porosity control and novel compositions of selected materials. In the last part, the applications of NHSG derived materials as heterogeneous catalysts and supports, luminescent materials and electrode materials in Li-ion batteries are described.

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Section: New Compositionsmentioning

confidence: 99%

The Power of Non-Hydrolytic Sol-Gel Chemistry: A Review

et al. 2017

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“…One such method is the non-hydrolytic sol gel (NHSG) process, which was shown to provide an elegant route to mixed metal oxides [60,61,62,63,64]. It was previously demonstrated that this chemistry can be applied to the synthesis of A 2 M 3 O 12 compounds.…”

Section: Introductionmentioning

confidence: 99%

Low Temperature Synthesis and Characterization of AlScMo3O12

et al. 2015

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Recent interest in low and negative thermal expansion materials has led to significant research on compounds that exhibit this property, much of which has targeted the A2M3O12 family (A = trivalent cation, M = Mo, W). The expansion and phase transition behavior in this family can be tuned through the choice of the metals incorporated into the structure. An undesired phase transition to a monoclinic structure with large positive expansion can be suppressed in some solid solutions by substituting the A-site by a mixture of two cations. One such material, AlScMo3O12, was successfully synthesized using non-hydrolytic sol-gel chemistry. Depending on the reaction conditions, phase separation into Al2Mo3O12 and Sc2Mo3O12 or single-phase AlScMo3O12 could be obtained. Optimized conditions for the reproducible synthesis of stoichiometric, homogeneous AlScMo3O12 were established. High resolution synchrotron diffraction experiments were carried out to confirm whether samples were homogeneous and to estimate the Al:Sc ratio through Rietveld refinement and Vegard’s law. Single-phase samples were found to adopt the orthorhombic Sc2W3O12 structure at 100 to 460 K. In contrast to all previously-reported A2M3O12 compositions, AlScMo3O12 exhibited positive thermal expansion along all unit cell axes instead of contraction along one or two axes, with expansion coefficients (200–460 K) of αa = 1.7 × 10−6 K−1, αb = 6.2 × 10−6 K−1, αc = 2.9 × 10−6 K−1 and αV = 10.8 × 10−6 K−1, respectively.

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“…Moreover, the NHSG route features different reactions and reaction conditions, which significantly affect the texture, homogeneity and surface chemistry of the resulting oxide [4][5][6]. In the past 20 years, several non-hydrolytic synthesis methods of oxides and mixed oxides have been described, involving the reaction of precursors (alkoxides, chlorides, acetylacetonates) with oxygen donors (ethers, alcohols, ketones) [4][5][6][7][8][9][10]. The main non-hydrolytic routes involve the reaction of a metal chloride with either a metal alkoxide or organic ether, acting as oxygen donors [7][8][9] as described in Figure 1.…”

mentioning

confidence: 99%

“…In the past 20 years, several non-hydrolytic synthesis methods of oxides and mixed oxides have been described, involving the reaction of precursors (alkoxides, chlorides, acetylacetonates) with oxygen donors (ethers, alcohols, ketones) [4][5][6][7][8][9][10]. The main non-hydrolytic routes involve the reaction of a metal chloride with either a metal alkoxide or organic ether, acting as oxygen donors [7][8][9] as described in Figure 1. On the other hand, the formation of alkyl halide and/or alkyl ethers as by-products and the potential incompatibility with oxygen containing species have to be taken into account as possible negative aspects.…”

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confidence: 99%