Fundamental studies and electrochemical applications of carbon nanotubes (CNTs) have impacted a wide range of disciplines. A key issue for CNT electrochemistry is to understand how the physical, chemical, and electronic properties of different CNT materials affect their electrochemical performance. We investigate the differences arising from CNTs undergoing mild (H2O2) or harsh (HNO3) oxidation processes. Morphological assessment and chemical characterization of CNT materials revealed that HNO3 treatment (CNT–HNO3) was effective in removing a large part of the metallic impurities, whereas H2O2 treatment (CNT–H2O2) was more proficient in eliminating carbonaceous imperfections in the starting CNT material (CNTprist). We investigated the electrocatalytic and electron-transfer properties of CNTprist and oxidized CNTs on a variety of electrochemical probes, which are sensitive to carbon surfaces as well as its oxygen-containing groups and/or metallic impurities. Electrochemical results show that, for the studied molecules, CNTprist and CNT–H2O2 exhibit mostly indistinguishable performances, whereas CNT–HNO3 yields an improved performance.
All Science Journal Classification (ASJC) codes