Condensation-Enhanced Self-Assembly as a Route to High Surface Area α‑Aluminas
Condensation-Enhanced Self-Assembly as a Route to High Surface Area α‑Aluminas
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DOI：
10.1021/cm401443b
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发表时间：
2013-10
影响因子：
8.6
通讯作者：
L. Pérez;V. Zarubina;H. J. Heeres;I. Melián-Cabrera
中科院分区：
文献类型：
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作者：
L. Pérez;V. Zarubina;H. J. Heeres;I. Melián-Cabrera
采用溶胶-凝胶法，在非离子表面活性剂（EO_（20）PO_（70）EO_（20））、HCl为催化剂和水（H_2O/Al = 6）存在下，由三仲丁醇铝在s-BuOH中水解凝胶蒸发诱导自组装（EISA）制备了高比表面积的纳米α-氧化铝。活化材料呈现约8.4-10 m2 g-1的中等表面积，与显著的微晶粗化相关。生产更小微晶的关键方面是使中间相更耐粗化。这是通过在蒸发之前用四丁基氢氧化铵（TBAOH）处理水解的凝胶来增强缩合步骤来实现的。的中间相的特性表明冷凝的初级颗粒与较少的AlO 5不饱和位点，在一个较低的固体产率的代价，由于小的微晶溶解。活性TBAOH凝聚型EISA材料由α-氧化铝聚集体和α-氧化铝颗粒组成。
High surface area nanosized α-alumina has been obtained by thermally treating a sol–gel-derived mesophase at 1200 °C; the mesophase was synthesized by a sol–gel route involving evaporation induced self-assembly (EISA) of a hydrolyzed gel from Al-tri-sec-butoxide in s-BuOH in the presence of a nonionic surfactant (EO20PO70EO20), HCl as catalyst, and water (H2O/Al = 6). The activated material renders moderate surface areas of about 8.4–10 m2 g–1, associated with significant crystallite coarsening. The key aspect to produce smaller crystallites is making the mesophase more resistant to coarsening. This was achieved by enhancing the condensation step by treating the hydrolyzed gel with tetrabutyl ammonium hydroxide (TBAOH) before evaporation. The characteristics of the mesophase indicate condensation of the primary particles with less AlO5 unsaturated sites, at the expense of a lower solid yield due to small crystallites dissolution. The activated TBAOH condensed EISA material is composed of α-alumina aggrega...