Electrochemical Hydrogen Storage of Multiwalled Carbon Nanotubes

Abstract

Electrochemical reduction of phenyl diazonium salts in acetonitrile at boron‐doped diamond electrodes yielded covalent bonding of aromatic groups to the carbon surface. Diamond surfaces modified with nitrophenyl, trifluoromethylphenyl, and nitroazobenzene showed strong X‐ray photoelectron spectroscopy (XPS) signals for surface nitrogen or fluorine, which were stable to exposure to air or solvents. Raman spectra of chemisorbed nitroazobenzene on boron‐doped diamond were obtained, and were similar to those observed for derivatized glassy carbon. Estimated surface coverages of 50–70% of a compact monolayer were calculated from XPS spectra, indicating that the coverage is too high to be attributed solely to modification of carbon impurities or boron dopant. The high coverages of covalently bonded molecules on diamond achievable by diazonium reduction imply that a variety of surface functionalities may be introduced on the normally unreactive diamond surface. ©1999 The Electrochemical Society