摘要
采用ＸＲＤ手段，研究了用镍盐浸渍过的Ｚｒ（ＯＨ）４经过高温焙烧后所得的ＺｒＯ２晶型变化情况。结果表明，镍盐的存在明显地抑制了四方ＺｒＯ２向单斜ＺｒＯ２转化过程。这种抑制作用是由于镍盐分解出的ＮｉＯ单层分散在载体ＺｒＯ２颗粒表面，阻止了ＺｒＯ２颗粒的进一步长大和颗粒间的烧结，从而避免了伴随的晶相转变。用ＸＲＤ相定量法测得４００℃、４５０℃、５００℃焙烧后的样品中ＮｉＯ在ＺｒＯ２载体表面的分散量分别为０．１０１ｇＮｉＯ／１００ｍ２ＺｒＯ２，０．０８５ｇＮｉＯ／１００ｍ２ＺｒＯ２和０．０６８ｇＮｉＯ／１００ｍ２ＺｒＯ２。这些测定值均小于按密置单层模型计算出的理论分散阈值０．１８３ｇＮｉＯ／１００２ＺｒＯ２。比表面的测定结果表明，镍盐含量为０．１０ｇＮｉＯ／ｇＺｒＯ２时，样品的比表面最大，并明显大于同样条件下所得的纯ＺｒＯ２的比表面。这归因于ＺｒＯ２颗粒表面的ＮｉＯ阻止了四方ＺｒＯ２颗粒的长大，从而维持大的比表面。
he transformation of crystalline ZrO2 produced by high temperature calcination of Ni-impregnated Zr(OH)4 is studied using XRD technology. The results show that Ni-containing compounds significantly inhibit the transformation of tetragonal zirconia to monoclinic.A quantitative determination by XRD is carried out for the samples obtained by calcination at different temperatures 400, 450 and 500℃, indicating that dispersion capacities of NiO on the surface of ZrO2 supports are 0. 101, 0. 085, and 0. 068 g NiO/100m2 ZrQ2,respectively, all less than the theoretical value of 0. 183. It is found by determination of surface areas that the sample with 0. 10 g NiO/g ZrO2 has the largest specific surface area, and even larger than pure ZrO2 produced under the same conditions, attributed to the crystalline growth of tetragonal ziaconia prevented by NiO dispersing on ZrO2 surface.
出处
《天然气化工—C1化学与化工》
CAS
CSCD
北大核心
1995年第3期1-4,共4页
Natural Gas Chemical Industry
关键词
氧化锆
晶型
比表面
镍盐
monolayer dispersion
tetragonal ZrO_2
monoclinic ZrO_2
specific surface area
supported catalys
