A novel WO2@FeWO4 composite derived from polyoxometalates@Fe-metal-organic frameworks and its electrochemical properties

作者：Zhang, Wanqiu; He, Xuan^*; Zhao, Lei; Li, Weixin; Fang, Wei; Chen, Hui; Xin, Zhaopeng

来源：Journal of Materials Science: Materials in Electronics , 2018, 29(17): 14612-14619.

DOI：10.1007/s10854-018-9597-8

• Keggin-type
• Needle-like
• Negative charge
• Polyoxometalates
• Positive electrodes
• Secondary building units
• Tungstophosphoric acid
• Valence state

In this paper, we synthesize a needle-like polyoxometalates@Fe-based metal-organic framework (POM@Fe-MOFs) composites, in which the Keggin-type W-based POM with negative charges exist as secondary building units of Fe-based MOFs. Based on the synthesized POM@Fe-MOFs, WO2@FeWO4 is easily prepared by appropriate thermal treatment. On the one hand, the derivative retains the original POM@Fe-MOFs morphology. Owing to the face that the Fe element contains variable valence state and the W element in tungstophosphoric acid exists in the form of high valence, both of which have great potential in the field of electrochemistry. According to the systematical characterization, the results show that WO2@FeWO4 composite can be used as positive electrodes in supercapacitors which is reported for the first time. In addition, the WO2@FeWO4 is confirmed to exhibit an excellent capacity of 124 F g(-1) at a current density of 0.5 A g(-1) in 6 M KOH when used in supercapacitors, which can be attributed to the redox reaction of W element.

• 出版日期2018-9
• 单位武汉科技大学