Ti/TiO₂ electrode preparation using laser anneal and its application to determination of chemical oxygen demand

A method for Ti/TiO₂ photoelectrode preparation using laser calcination instead of oven calcination process was introduced. The prepared TiO₂ film was investigated by X-ray diffraction (XRD), electrochemical impedance spectroscopy (EIS) and amperometry, and it was found that the prepared electrode mainly consisted of anatase TiO₂ nanoparticles on its surface and exhibited a superior photocatalytic activity. The electrode was employed as a sensor to measure chemical oxygen demand (COD) of the wastewater. The measuring principle was based on the photocurrent responses of the electrode which were proportional to the COD values. Under the optimized experimental conditions, the linear range was 50-2000 mg L ^-1, and the detection limit was 16 mg L-1 (S/N = 3). This method was characterized by short analysis time, simplicity, low environmental impact and long lifetime of the sensor. Additionally, the COD values obtained from the proposed and conventional methods agreed well as demonstrated by the high significant correlation between the two sets of COD values (R = 0.9895, n = 25).