氧化镍纳米晶体的制备及其过程分析

为了开发一种新型纳米氧化镍催化剂,能有效地应用于生物质气化过程中去除焦油,本文采用均匀沉淀法成功地制备了纳米氧化镍晶体,并利用TGA、FTIR、XRD、BET、YEM等分析手段对前驱体和产品的性能进行了表征.同时,对前驱体的分解过程进行了全面的分析.分析结果表明前驱体是水合碱式碳酸镍,其分子式为NiCO3·Ni(OH)2·nH2O,它能在360℃下完全分解转化为纳米NiO,同时煅烧条件对合成纳米NiO的晶体粒径影响很大.实验证实所得纳米NiO颗粒呈球形,分散性好,纯度较高,属立方晶系结构,平均粒径约为7.5nm,其BET表面积为187.98m2/g,这显示纳米NiO晶体具有作为高效催化材料的应用可行性.

Preparation of Nanocrystalline NiO and Process Analysis

The objective of this study is to develop a novel and effective nano-NiO catalyst to be used in biomass gasification for tar removal. For this purpose, in this study, nanocrystalline NiO particles were successfully prepared by the homogeneous precipitation method, and different approaches including thermogravimetric analysis, Fourier transforms infrared spectrometry, X-ray diffraction, BET surface area measurement and transmission electron microscopy were used to characterize the nano-NiO particles and its precursors. Meanwhile, the process of the nanocrystalline NiO particles derived from precursors was thoroughly analyzed. The analysis results indicated that the as-synthesized precursor was hydrated nickelbasic carbonates and its formula was identified as NiCO3 · 2Ni(OH)2 · nH2O, and it can completely transform into nanocrystalline NiO particles below 360℃ under the air atmosphere. Furthermore, the effect of calcination conditions on the crystalline size of nanocrystalline NiO are very crucial. The prepared NiO nanoparticles were found spherical in shape, could be well dispersed and demonstrated weak agglomeration. They had generally high purity and a fine crystal phase of cubic syngony with a mean size of about 7.5nm and specific surface area of 187.98 m2/g, the high specific surface areas of the NiO nanoparticles suggested its possibility of application as efficient catalytic materials.