WCu复合粉体的溶胶-凝胶制备及其还原行为研究

Preparation of WCu Composite Powders by Sol-Gel Method and Their Reduction Behavior

摘要:

以偏钨酸铵和硝酸铜为原料，柠檬酸为络合剂的溶胶-凝胶法制备WCu复合粉体。利用XRD和TEM对还原前后粉末的物相组成﹑形貌﹑粒度进行分析。TEM显示还原后WCu粉末粒度在100 nm左右，Cu相均匀包覆在W颗粒表面。对氧化物粉体的还原性能和机理进行了系统的分析。程序升温还原(TPR)确定了氧化物粉体最佳的两步还原温度分别为500和700 ℃。红外光谱(FT-IR)分析表明，铜通过氧与钨键合，削弱W-O-W键，使得钨铜复合氧化物还原性增强。

Abstract:

WCu composite powders were prepared by the sol-gel method with Cu(NO3)2·3H2O and (NH4)6H2W12O40·5H2O as raw materials and citric acid as chelating reagent. The composition, morphology and particle size of the powders were studied by XRD and TEM. TEM observation results show that the particle size of WCu powders is about 100 nm after reduction and the W grains were covered homogeneously by Cu on the surface. The reduction behavior and mechanism of the oxide powders were analyzed systematically. Temperature programmed reduction (TPR) result indicates that the appropriate two-step reduction temperatures are 500 and 700 oC. The FT-IR analyses reveal that the bond of W-O-W is weakened due to the bond of Cu-O-W, leading to the increase of the reduction properties of the WCu composite oxide powders.