Structure and reactivity of CNT/manganese oxide nanocomposites

摘要

There has been enormous interest in composite materials based on carbon nanotubes-also called "hybrid" or "meta nanotubes"-in recent times. A variety of such materials based on filled and/or decorated nanotubes has been prepared. CNT/manganese oxide nanocomposites are interesting notably for their electrochemical properties for use as supercapacitors. Here we present an easy two-step route to such composites by using a manganese nitrate solution in nitric acid. The nitrate can be selectively decomposed to amorphous MnO_x. Products based on various types of CNT (single-, double-, multi-walled) have been prepared and characterized by TEM, thermal analysis (TG/DTA, DSC), nitrogen adsorption, Raman spectroscopy, and X-ray diffraction. A remarkable increase in reactivity towards oxidation is observed for the carbon backbone, compared to a purely physical mixing of CNT and MnO_2. This means that the contact at the nanoscale between oxide and carbon enhances the catalytic behavior of the former. Thus, these nanocomposite materials may find an application in future energetic systems, such as nanothermites.