As BDD is known not to be electrochemically active for H2O2 oxidation–reduction,
modifying Pt particles at the surface of BDD can be acted
through a micro or nano-electrode array [8,9]. Therefore, although the
oxidation reduction currents are lower than those at the Pt bulk electrode,
the background currents are also very low, resulting in high signal
to background (S/B) ratio. From Fig. 4b and c, the S/B ratio was 1.3 for
the Pt electrode, whereas it was 18 for the Pt-BDD electrode. Generally,
high S/B ratio generates better limits of detection. Furthermore, more
loading of Pt particles on the surface of BDD can increase the currents
of oxidation–reaction of H2O2, although the background currents also
increase. Summary of S/B ratios of the cyclic numbers from 20, 40, and
80 was shown in Fig. 4d. The S/B ratio of the oxidation peak shows an
increase from 20 to 80 cycles, while the decreases were shown at the
cyclic numbers higher than 80. Similar behavior was also shown for
the reduction peak, therefore, based on the result cyclic number of 80
was applied for the next experiments