Synthesis, crystal structure and thermal stability of tetrahydroborate sodalite Na8[AlSiO4]6(BH4)2

Buhl, Josef‐Christian; Gesing, Th.M.; Rüscher, Claus H.

doi:10.1016/j.micromeso.2004.11.022

Cited by 50 publications

(47 citation statements)

References 27 publications

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“…The crystal structure of the mineral sodalite is known since decades [7] [8] [9]. As a member of the sodalite group the crystal structure of NaBH 4 sodalite consists of a three-dimensional network of crosslinked TO 4 tetrahedra (T = Si, Al) [2]. Polyhedral units in form of truncated octahedral cages ("toc-units") in a space-filling array can be well distinguished as larger building blocks of the whole framework.…”

Section: Bhmentioning

confidence: 99%

“…This ion complex is in fast rotational motion whereby the six-ring openings of the toc-unit are blocked by the sodium cations. Reactants like water molecules cannot enter the toc and the highly reactive and moisture sensitive BH 4 -anion is protected according this structural arrangement (the first synthesized Na 4 BH 4 sodalite sample is still in perfect order since more than ten years [2]). …”

Section: Bhmentioning

confidence: 99%

“…An image of a sample "BH 4 -hydro" observed under common hydrothermal conditions (20 ml Figure 5. SEM photographs of products A2 -A4 of autothermal syntheses (Table 1) and a sample from conventional hydrothermal synthesis [2] "BH 4 -hydro" (down right).…”

Section: -Autothermal Synthesis Of Nabh 4 -Sodalitementioning

confidence: 99%

“…16 M NaOH, temperature 120˚C, reaction time 24 h, as described in [2]) is included in Figure 5 -NaBH 4 -sodalites by crossover synthesis from aqueous gel solution to NaOH melt flow…”

Section: -Autothermal Synthesis Of Nabh 4 -Sodalitementioning

confidence: 99%

“…As a first model case for protecting this highly reactive salt from hydrolysis reaction, tetrahydroborate can be incorporated into the micropores of zeolite sodalite (SOD) [2]. The resulting 4 …”

Section: Introductionmentioning

confidence: 99%

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NaBH<sub>4</sub> Sodalites, Synthesized by Modified Methods: (1) Autothermal Synthesis and (2) Crossover Reaction from Gel to Melt Flow

Buhl¹

2017

ACES

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NaBH 4 sodalites were obtained by two new modified methods of crystallization: (1) autothermal synthesis and (2) crystallization with crossover from gel to melt flow in NaOH flux. Syntheses results were presented according to XRD, SEM and FTIR. Besides important features of both synthesis procedures product properties like crystal size and morphology were investigated. Spherical agglomerates of microcrystalline sodalite of composition Na 7 [AlSiO 4 ] 6 BH 4 (H 2 O) 2 were already observed after 4 h without any external heating by the autothermal procedure. Sodalites of the same average composition but in form of agglomerated nanoparticles are crystallized after very short times (2 h 30') by the crossover reaction from gel to melt flow. Hydrogen release by heating was further studied for two selected samples with comparable composition from each synthesis procedure. Total hydrogen release by hydrolysis reaction with the internal cage water was found during heating of the autothermal product in synthetic air up to 550˚C. In contrast hydrogen release from the nanocrystalline sample of crossover synthesis was not completed when heated under the same conditions. These differences were discussed in terms of crystal size and an earlier loss of the internal water from the nanocrystals of the crossover synthesis.

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Section: Bhmentioning

confidence: 99%

Section: Bhmentioning

confidence: 99%

Section: -Autothermal Synthesis Of Nabh 4 -Sodalitementioning

confidence: 99%

“…16 M NaOH, temperature 120˚C, reaction time 24 h, as described in [2]) is included in Figure 5 -NaBH 4 -sodalites by crossover synthesis from aqueous gel solution to NaOH melt flow…”

Section: -Autothermal Synthesis Of Nabh 4 -Sodalitementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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NaBH<sub>4</sub> Sodalites, Synthesized by Modified Methods: (1) Autothermal Synthesis and (2) Crossover Reaction from Gel to Melt Flow

Buhl¹

2017

ACES

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Mechanical Strength Development of Geopolymer Binder and the Effect of Quartz Content

Rüscher

Schulz

Gougazeh

et al. 2013

Ceramic Engineering and Science Proceedings

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Sodium tetrahydroborate (NaBH 4 = SB) and ammonia-borane (NH 3 BH 3 = AB) were dissolved in sodium aluminate and silicate solutions. Bringing them together caused immediate gel formation and recrystallization of SB and AB during drying. The gel forms geopolymer (G) type units, which enclose and protect the SB and AB crystals inside. SB-G composites are stable over a long time without any loss in SB. An optimized SB-G releases about 1820 L hydrogen per kg, i.e. containing an equivalent of about 80 % of pure SB (2270 L/kg) obtained by means of acidic titration. SB and SB-G remain stable up to 400 °C in vacuum and under inert gas conditions (He, Ar, N 2 ). In air, a reaction starts at about 240 °C, leading to a complete transformation to NaBO 2 above about 320 °C. For SB-G, this reaction is retarded by 50 °C. In the case of AB-G, IR-absorption spectra indicate that the geopolymer matrix consists of mainly sialate units (Si-O-Al-O). Heating experiments at temperatures of 120, 150 and 300 °C show the formation of polyaminoboranes (PAB) and polyiminoboranes (PIB). The underlying reactions could be related to hydrogen release in two exothermic peaks observed at around 122 °C and 160 °C. There are strong indications that DADB, the diammoniate of diborane, (NH 3 BH 2 )[BH] 4 , forms prior to hydrogen release in the first step.

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Basic Research on Geopolymer Gels for Production of Green Binders and Hydrogen Storage

Rüscher¹,

Schomborg²,

Schulz³

et al. 2013

Ceramic Engineering and Science Proceedings

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Synthesis, crystal structure and thermal stability of tetrahydroborate sodalite Na8[AlSiO4]6(BH4)2

Cited by 50 publications

References 27 publications

NaBH<sub>4</sub> Sodalites, Synthesized by Modified Methods: (1) Autothermal Synthesis and (2) Crossover Reaction from Gel to Melt Flow

NaBH<sub>4</sub> Sodalites, Synthesized by Modified Methods: (1) Autothermal Synthesis and (2) Crossover Reaction from Gel to Melt Flow

Mechanical Strength Development of Geopolymer Binder and the Effect of Quartz Content

Basic Research on Geopolymer Gels for Production of Green Binders and Hydrogen Storage

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Synthesis, crystal structure and thermal stability of tetrahydroborate sodalite Na8[AlSiO4]6(BH4)2

Cited by 50 publications

References 27 publications

NaBH&lt;sub&gt;4&lt;/sub&gt; Sodalites, Synthesized by Modified Methods: (1) Autothermal Synthesis and (2) Crossover Reaction from Gel to Melt Flow

NaBH&lt;sub&gt;4&lt;/sub&gt; Sodalites, Synthesized by Modified Methods: (1) Autothermal Synthesis and (2) Crossover Reaction from Gel to Melt Flow

Mechanical Strength Development of Geopolymer Binder and the Effect of Quartz Content

Basic Research on Geopolymer Gels for Production of Green Binders and Hydrogen Storage

Contact Info

Product

Resources

About

NaBH<sub>4</sub> Sodalites, Synthesized by Modified Methods: (1) Autothermal Synthesis and (2) Crossover Reaction from Gel to Melt Flow

NaBH<sub>4</sub> Sodalites, Synthesized by Modified Methods: (1) Autothermal Synthesis and (2) Crossover Reaction from Gel to Melt Flow