.
Hydrodynamic amperometry was used to study the photoelectrochemical
response of Ti/TiO2 electrode, in buffer solution
in the absence and presence formaldehyde with two various
concentrations under UV irradiation. The results are shown in
Fig. 5. It can be seen that the rise and fall of the photocurrent
corresponded well to the illumination being switched on and off.
The generation of photocurrent consisted of two steps. The first
step of the photocurrent appears promptly after the illumination,
and the second step of the photocurrent reaches a steady state.
This pattern of photocurrent is highly reproducible for several on–
off cycles of illumination. The results of hydrodynamic amperometry
were consistent with observations of cyclic voltammetry.
The current response on the Ti/TiO2 electrode in dark is insignificant
in the absence and presence of formaldehyde which means
that no electrochemical oxidation occurred. Under illumination,
a significant increase in the photocurrent is observed wherein
the value of this increase is smaller in the absence of formaldehyde
than that o