Increasing the Electric Double-Layer Capacitance in Boron-Doped Diamond Electrodes

Highly boron-doped diamond (BDD) electrodes containing sp(2) carbon impurities exhibit an increase in the electric double-layer capacitance (C-dl) after anodic oxidation. Although it is known that the electrochemical properties of BDD electrodes are affected by several factors, including the boron concentration, the amount of sp(2) carbon impurity, and the surface termination and orientation, clarification of the mechanism for the increase in C-dl needs to be done. To this end, we prepared several BDD samples under various conditions and the properties of these samples, including C-dl, were systematically investigated. The mechanism for the increase in C-dl in particular, including the effect of the surface termination, is discussed.