3.2. Potential window of the hybrid diamond/graphite electrodes
The potential window of a working electrode is an important
concern while considering its applications in electrochemistry. In
this work, a series of hybrid diamond/graphite films were fabricated
at different methane concentrations (7%, 8% and 9%, with other
parameters unchanged) and the potential windows of the hybrid
electrodes were evaluated in 0.1 M H2SO4 solution. The results
are shown in Fig. 3. The potential window of B-doped diamond
electrode is also shown as a comparison. In Fig. 3, the hybrid diamond/
graphite film with 7% methane barely shows any response,
which is an indicator for slow kinetics on the electrode. This may be
due to the high sheet resistance (10–100 k/square) of this sample.
The hybrid diamond/graphite film with 8% methane possesses
a wide potential window of 3.1 V from
−1.2 V to 1.9 V, which is com-