程序升温还原技术对Cu-Al尖晶石材料的表征识别

Characterization and identification of Cu-Al spinel materials via H_(2)-TPR technique

通过机械球磨和固相焙烧的方法合成了组成不同的纳米铜铝尖晶石材料,采用X射线粉末衍射、高分辨透射电镜和程序升温还原技术(H_(2)-TPR)对其进行了表征,结果发现:基于H_(2)-TPR技术能够表征识别Cu-Al尖晶石固溶体与计量CuAl_(2)O_(4)尖晶石,并可得出合成样品中Cu-Al尖晶石晶相的分子式。H_(2)-TPR分析条件的研究表明:称样质量、气体流速、升温速率和热导电流等对还原峰温度和强度有明显的影响,但样品中不同铜物种的相对含量保持基本不变,证明了基于H_(2)-TPR技术表征识别Cu-Al尖晶石的可靠性和合理性。对一定组成的Cu-Al尖晶石样品,适宜的H_(2)-TPR分析条件应综合考虑称样质量、气体流速、升温速率和热导电流。

The nano Cu-Al spinel materials with different Cu states were synthesized by mechanical ball milling and solid-phase calcination methods,and were characterized by x-ray powder diffraction,high resolution transmission electron microscopy and temperature programmed reduction technology(H_(2)-TPR).The results showed that the H_(2)-TPR can be used to characterize and identify Cu-Al spinel solid solution and stoichiometric CuAl_(2)O_(4) spinel,and the molecular formula of Cu-Al spinel phase can be obtained.The study of H_(2)-TPR operation conditions shows that the sample quality,gas flow rate,heating rate and thermal conductivity current have significant effects on the reduction temperature and intensity of H_(2)-TPR peaks.Importantly,the relative content of different copper species in the sample remains almost unchanged,indicating the feasibility and rationality of H_(2)-TPR method for identifying Cu-Al spinel.Besides,the appropriate H_(2)-TPR analysis conditions for Cu-Al spinels should consider several factors simultaneously,including sample weight,gas flow rate,heating rate and thermal conductivity current.