Photoelectrochemistry on a planar, interdigitated electrochemical cell

The construction of a planar electrochemical cell with two interdigitated electrodes, with a finger spacing of 25–100 μm and 200–50 pairs of fingers and gaps, respectively, is described. The working electrode consists of n-type semiconducting titanium dioxide (anatase). Under UV light, photocurrents are produced. No reduction in the photocurrent due to iR drop was observed, even in electrolytes of low ionic strength. This makes the device an interesting candidate for photoelectrocatalytic purification of drinking water. An example is shown in the degradation of the azo-dye AO7 (acid orange 7). k(photoelectrocatalysis) on a device with 50 finger pairs was 3.29 × 10−6/s and the corresponding kinetic parameter, p = kFV/iphoto (rate constant normalized to unit volume and photocurrent), was 404 M−1.

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► A planar electrochemical cell with two interdigitated electrodes is described.
► One electrode consists of semiconducting n-type TiO2.
► Finger width and spacing is kept to ≤100 μm.
► Currents are not diminished by iR drop in electrolytes of low conductance.
► Organics are photoelectrocatalytically degraded under UV light and electrical bias.