Novel photoelectrocatalytic approach aiming at the digestion of water samples, estimation of organic matter content and stripping analysis of metals in a special UV-LED irradiated cell with a TiO2-modified gold electrode

作者：Baccaro Alexandre L B; Gutz Ivano G R^*

来源：Electrochemistry Communications, 2013, 31: 28-30.

DOI：10.1016/j.elecom.2013.03.001

• UV-LED photoelectrochemical cell
• Gold-TiO2 electrode
• Cu(II)-EDTA photovoltammetry
• Trace metal stripping voltammetry
• EDTA photooxidation
• Photoelectrocatalytic sample treatment

Fast photoelectrocatalytic degradation of organic matter is proposed as a means to estimate the organic load and in situ sample preparation for concomitant trace metal determination by voltammetry. To prove this concept, a thin-layer type flow-through cell comprising a UV-LED focused on a gold disc working electrode, modified with TiO2 nanoparticles (P25, mainly anatase) embedded into an electrodeposited gold film, was developed and evaluated with the model system Cu(II)-EDTA plus EDTA in excess. Consecutive cyclic voltammograms (-0.3 to +0.7 V vs. Ag/AgCl) exhibited no peaks in the dark, whereas under irradiation (370 nm, approximate to 150 mW) unchelated copper ions were reduced and reoxidised as usual in anodic stripping voltammetry (ASV), denoting the degradation of EDTA near the interface by photogenerated valence-band free holes or indirectly by (OH)-O-center dot radicals. The photocurrent due to conduction-band electrons withdrawal, additively superimposed on the voltammograms, increased with the electrode potential and with the EDTA concentration, thus allowing an estimation of the organic load in the samples. Full depletion of EDTA from the solution layer was found to be unnecessary and the high 'baseline' provided by the photocurrent could be avoided by performing ASV immediately after switching off the LED.

• 出版日期2013-6