摘要
分别使用三种方法制备了NiP非晶态合金:次磷酸钠还原镍盐(方法1)、次磷酸镍自分解(方法2)和使用有机胺调节溶液pH值的次磷酸还原镍盐(方法3)。研究了产品的物性,并以环丁烯砜加氢反应为探针检测了NiP非晶态合金的催化活性。研究结果表明,次磷酸钠体系制备的产品性质比较稳定,条件的改变对产物性质的影响不显著,催化活性一般在50%～60%之间;次磷酸镍体系中制备的样品显示出较高的催化活性,环丁烯砜转化率在90%以上;次磷酸体系制备样品的性质对条件变化较为敏感,催化剂的活性在70%～98%之间波动。发现方法2得到的NiP非晶态合金呈现为分散的完美的球形颗粒,且颗粒之间不存在聚集现象;使用方法3可以得到高比表面积的NiP非晶态合金。两种新方法所制备的NiP非晶态合金具有较小的粒径、较高的比表面积、较高的热稳定性和较高的催化反应活性。
NiP amorphous alloy catalysts were prepared via three different ways, reduction of Ni2+ by NaH_2PO_2 (method 1), self-oxidation-and-reduction of Ni(H_2PO_2)_2 (method 2), and the reduction of Ni2+ by H_3PO_2 with amine adjusting the pH value of solution (method 3). All the NiP samples have amorphous structure inferred from the X-ray Diffraction (XRD) patterns. But the catalysts prepared by the two new methods show smaller particle size and higher surface area than the samples by method 1, and they show higher catalytic activity in the hydrogenation of sulfolene evaluated in a 250mL autoclave. In order to exhibit the influence of preparation methods on properties of NiP samples, three samples were prepared at the same conditions via different ways, respectively, which were signed as NiP-4 (from method 1), NiP-5 (from method 2) and NiP-9 (from method 3). Transmission Electron Microscope (TEM) images show these samples have different shapes and sizes. NiP-4 sample has not very regular shape. NiP-5 particles are isolated balls while the shape of NiP-9 is near spherical. Their average particle sizes are about 160nm, 30nm and 10nm, respectively. Extend of surface oxidation increases with the particle size decreasing. Crystallization performance of these amorphous alloys is determined by Differential Scanning Calorimetry (DSC) analysis. Their crystallization temperature is in the order of NiP-9 (682K) > NiP-5 (679K) > NiP-4 (625K), which means their structure stability in the same order.
出处
《燃料化学学报》
EI
CAS
CSCD
北大核心
2004年第3期351-356,共6页
Journal of Fuel Chemistry and Technology
基金
国家自然科学基金(20003006)
天津市自然科学基金(031606211)。 ~~
关键词
NiP非晶态合金
次磷酸钠
次磷酸镍
次磷酸
环丁烯砜
加氢反应
NiP amorphous alloy
sodium hypophosphite
nickel hypophosphite
hypophosphite acid
sulfolene
hydrogenation
