A heat-resisting acid catalyst: Thermal stability and acidity of a thin silica layer on alumina calcined at 1493 K†
A heat-resisting acid catalyst: Thermal stability and acidity of a thin silica layer on alumina calcined at 1493 K†
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耐热酸催化剂：1493 K 下煅烧的氧化铝上二氧化硅薄层的热稳定性和酸性
DOI：
10.1002/cvde.19950010205
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发表时间：
1995
期刊：
影响因子：
--
通讯作者：
M. Niwa
中科院分区：
文献类型：
--
作者：
N. Katada;Hideaki Ishiguro;Koh;M. Niwa
在氧化铝上化学气相沉积一薄层二氧化硅可以改善氧化铝烧结时的热稳定性，并减少氧化铝加热时的表面积损失。苯甲醛-氨滴定表明，高稳定性的样品几乎完全被二氧化硅覆盖。这些观察结果表明，超薄的二氧化硅层，可能是单层的，使表面热稳定。即使在1493 K下煅烧后也观察到勃朗斯特酸：它最初被这种煅烧减少，但暴露于潮湿的气氛中很容易恢复，而传统的固体酸催化剂在完全烧结后不可逆地失活。
The chemical vapor deposition of a thin layer of silica on alumina is shown to improve the thermal stability of alumina with respect to sintering and to reduce the loss of surface area of alumina during heating. Benzaldehyde-ammonia titration showed that samples with high stability were almost completely covered by silica. These observations suggest that an ultrathin silica layer, probably a monolayer, thermally stabilizes the surface. Bronsted acidity was observed even after calcination at 1493 K: it was initially diminished by this calcination, but readily recovered on exposure to a humid atmosphere, whereas conventional solid-acid catalysts are irreversibly deactivated by complete sintering.