Abstract Hydrogen-selective silica membranes were prepared on a macroporous alumina support by chemical vapor deposition (CVD) of vinyltriethoxysilane (VTES) at 873 K at atmospheric pressure. The membrane had a high H2 permeance of 5.4 × 10−7 mol m−2 s−1 Pa−1 with H2 selectivity over CO2, N2, CO and CH4 of 95, 170, 170 and 480, respectively. In situ Fourier transform infrared (FTIR) measurements after CVD on an alumina disk at the same conditions as for the membrane preparation showed that the vinyl groups remained in the silica structure. The VTES-derived membrane had higher hydrothermal stability than a pure tetraethoxyorthosilicate (TEOS)-derived silica membrane, during exposure to 16 mol% water vapor at 872 K for 72 h. The temperature dependence of the permeance of various molecules (He, Ne, H2, CO2, N2, CO, CH4) before and after hydrothermal treatment gave information about the mechanism of permeance and the structure of the membrane. The membrane was composed of a contiguous silica network through which small species permeated by a solid-state mechanism and a small number of pores through which the large molecules diffused. The silica-based structure became more compact after hydrothermal treatment with decreasing permeance of small molecules (He, Ne, H2), while small pores were enlarged increasing permeance of large molecules (CO2, N2, CO, CH4). Calculation results for the small species based on a mechanism involving jumps of the permeating species between solubility sites showed lower activation energy and larger jump distances than those of a TEOS-derived silica membrane. The retention of the vinyl groups in the structure mostly associated with the defect pores resulted in interactions with CH4 and CO2, so that these species permeated by a surface diffusion mechanism.

中文翻译：

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乙烯基三乙氧基硅烷化学气相沉积制备氢选择性二氧化硅膜的合成与表征

摘要 通过乙烯基三乙氧基硅烷 (VTES) 在 873 K 大气压下的化学气相沉积 (CVD) 在大孔氧化铝载体上制备氢选择性二氧化硅膜。该膜具有 5.4 × 10-7 mol m-2 s-1 Pa-1 的高 H2 渗透率，H2 对 CO2、N2、CO 和 CH4 的选择性分别为 95、170、170 和 480。在与膜制备相同的条件下，在氧化铝盘上进行 CVD 后的原位傅里叶变换红外 (FTIR) 测量表明乙烯基保留在二氧化硅结构中。在 872 K 下暴露于 16 mol% 水蒸气 72 小时期间，VTES 衍生膜比纯四乙氧基原硅酸盐 (TEOS) 衍生二氧化硅膜具有更高的水热稳定性。各种分子（He、Ne、H2、CO2、N2、CO、CH4) 在水热处理前后提供了关于渗透机制和膜结构的信息。该膜由连续的二氧化硅网络组成，小物质通过固态机制渗透通过该网络，以及大分子通过其扩散的少量孔。水热处理后二氧化硅基结构变得更加致密，小分子（He、Ne、H2）的渗透性降低，而小孔扩大，大分子（CO2、N2、CO、CH4）的渗透性增加。基于渗透物质在溶解位点之间跳跃的机制，小物质的计算结果显示出比 TEOS 衍生的硅胶膜更低的活化能和更大的跳跃距离。