Synthesis of size-controlled boehmite sols: application in high-performance hydrogen-selective ceramic membranes,Journal of Materials Chemistry A

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Synthesis of size-controlled boehmite sols: application in high-performance hydrogen-selective ceramic membranes
Journal of Materials Chemistry A ( IF 10.7 ) Pub Date : 2022-06-06 , DOI: 10.1039/d2ta03148e
Hongsheng Wang ₁ , Sean-Thomas B. Lundin ₁ , Kazuhiro Takanabe ₁ , S. Ted Oyama _{1,

2,

3}

Affiliation

A hydrogen-selective silica–tantala composite membrane was prepared by chemical vapor deposition (CVD) of tetraethyl orthosilicate (TEOS) and tantalum ethoxide (TaEO) at 650 °C. The membrane composite consisted of a thin (ca. 15 nm) silica–tantala toplayer, a graded γ-alumina interlayer, and a porous zirconia tubular support. The graded γ-alumina interlayer was deposited via a sol–gel process using progressively smaller mono-dispersed boehmite (AlOOH) sols, with the boehmite sol nanoparticle size optimized by adjusting the solution pH and aging time. The resultant ceramic membrane exhibited high H₂ selectivities over CH₄, N₂, and O₂ of 16 000, 5000, and 640, respectively, with an H₂ permeance of 1.4 × 10⁻⁷ mol m⁻² s⁻¹ Pa⁻¹ at 650 °C. Exposure to 16 mol% steam at 650 °C for 200 h caused an H₂ permeance decline of 25%, and simultaneous H₂ selectivity increase over CH₄, N₂ and O₂ to 71 900, 42 600 and 2460, respectively. The hydrothermal stability and the final H₂ selectivities are the highest ever reported for silica-based membranes. The high performance is attributed to the defect-free deposition of the silica–tantala layer due to the optimization of the graded γ-alumina interlayer. Optimization of boehmite sol particle size and stability is crucial for state-of-the-art membranes, with these results also applicable in different fields.

中文翻译：

尺寸可控勃姆石溶胶的合成：在高性能氢选择性陶瓷膜中的应用

在 650 °C 下，通过原硅酸四乙酯 (TEOS) 和乙醇钽 (TaEO) 的化学气相沉积 (CVD) 制备氢选择性二氧化硅-钽复合膜。膜复合材料由薄（约15 nm）二氧化硅-钽顶层、渐变 γ-氧化铝夹层和多孔氧化锆管状支撑组成。通过溶胶-凝胶工艺使用逐渐变小的单分散勃姆石 (AlOOH) 溶胶沉积梯度 γ-氧化铝中间层，通过调节溶液 pH 值和老化时间优化勃姆石溶胶纳米颗粒尺寸。所得陶瓷膜对 CH ₄、N ₂和 O _{2表现出高 H}₂选择性，分别为 16 000、5000 和 640，H₂磁导率为 1.4 × 10^-7 mol m^-2 s^-1 Pa^-1在 650 °C。在 650 °C 下暴露于 16 mol% 的蒸汽 200 小时导致 H₂渗透率下降 25%，同时 H₂对 CH₄、N₂和 O₂的选择性分别增加到 71 900、42 600 和 2460。水热稳定性和最终H₂硅基膜的选择性是有史以来最高的。由于梯度γ-氧化铝中间层的优化，高性能归因于二氧化硅-钽层的无缺陷沉积。勃姆石溶胶粒径和稳定性的优化对于最先进的膜至关重要，这些结果也适用于不同的领域。

更新日期：2022-06-06

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