γ-AlOOH纳米棒的制备及其热分解

Preparation and Thermal Decomposition of γ-AlOOH Nanorods

以氯化铝、氢氧化钠为原料,在反应溶液的pH值为5、反应温度为200℃的条件下用液相法制备薄姆石(γ-AlOOH)纳米棒;对其在不同温度下的煅烧产物及在加热过程的热分解过程进行了分析。结果表明:试验条件下能制备出直径10～30 nm、长度100～300 nm的γ-AlOOH纳米棒;该纳米棒在500～1 200℃下煅烧后转变为γ-Al_2O_3仍保持纳米棒的形貌;在1 250℃下煅烧后转变产物为α-Al_2O_3;在1 300℃下煅烧后转变产物为α-Al_2O_3,纳米棒相互烧结形成团聚体;γ-AlOOH纳米棒的热分解过程分为物理吸附水的脱出、化学吸附水的脱出、结构水脱出并转变为氧化铝中间相、氧化铝中间相中残留羟基的脱出四个阶段。

Boehmiteγ-AlOOH nanorods were prepared through liguid phase method at 200℃in the solution with pH value of 5,using aluminum chloride and sodium hydroxide as raw materials.The products calcinated at different temperatures and the thermal decomposition of the products during heating were analyzed.The results show thatγ-AlOOH nanorods with diameter of 10-30 nm and length of 100-300 nm could be obtained under the test condition.The nanorods transformed toγ-Al_2O_3 when they were calcinated at 500-1 200℃.Theα-Al_2O_3 andθ-Al_2O_3 were generated at 1 250℃.Theα-Al_2O_3 was generated at 1 300℃and the nanorods formed aggregates after calcinating.The course of thermal decomposition ofγ-AlOOH nanorods was divided into four stages,including desorption of physisorbed water,desorption of chemisorbed water,conversion into transition alumina and dehydration of transition alumina.