Voltammetry at boron-doped diamond electrodes in liquid ammonia: Solvent window effects and diamond surface modification

Vacuum-annealed highly boron-doped diamond (BDD) thin-film electrodes are s hown to allow reversible voltammetric responses for the reduction of nitrob enzene, 3,5-difluoronitrobenzene, and for the generation of solvated electr ons in liquid ammonia at -60 degrees C. In liquid ammonia (0.1 M KI) a cons iderably extended positive potential window at BDD electrodes compared to p latinum is observed. At the negative end of the potential scale facile gene ration of solvated electrons occurs at both platinum and BDD electrodes. Af ter exposure to solvated electrons in liquid ammonia, the surface of the di amond becomes hydrophilic and nitrogen functionalities were detected by X-r ay photoelectron spectroscopy. (C) 2000 The Electrochemical Society. S1099- 0062(99)12-109-6. All rights reserved.