Improvement of electrochemical performance of screen-printed carbon electrodes by UV/ozone modification

Screen-printed carbon electrode (SPCE) has been widely used in electrochemical (EC) field. Nevertheless, compared with some metal electrodes, SPCE is not sensitive to small amounts of reagent owing to its relatively low electron transfer rate. In this paper, the UV/ozone modification was proposed to treat SPCE to improve its electron transfer rate and EC performance. The changes of SPCE morphology and composition induced by UV/ozone modification were investigated in detail. The results show that the improved electron transfer rate can be mainly attributed to the increase of oxygen functional groups. To clarify the essential EC characterization, potentiodynamic polarization and electrochemical impedance spectroscopy of K₃[Fe(CN)₆] was studied. Furthermore, to demonstrate the improved EC effect, two typical samples: small-molecule K₃[Fe(CN)₆] and macro-molecule nicotinamide adenine dinucleotide (NADH), were measured by cyclic voltammetry. After UV/ozone modification, the oxidation potential and peak current responses to K₃[Fe(CN)₆] and NADH were obviously improved in both original and CNT-modified SPCEs. Whereas, the original SPCE is more suitable to measure macromolecule NADH rather than CNT-modified one as the oxidative products of NADH are more likely to adsorb on rough surface.