Photocatalytic Self-Cleaning Electrochemical Sensor for 4-Nitrophenol detection

Electrode fouling and passivation are the main reasons for attenuated the electrochemistry signals. In this work, a renewable electrode for determination of 4-nitrophenol (4-NP) which not only has excellent detection signals but also can be photo-catalytically refreshed to remain the selectivity and sensitivity was been created. The GO/TiO2-CuTCPP composite material was characterized by Transmission electron microscopy (TEM), X-ray diffraction (XRD), electrochemical impedance spectroscopy (EIS), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectra (FT-IR). The electrochemical behavior of 4-NP on GO/TiO2-CuTCPP/GCE was investigated by cyclic voltammetry (CV) and square wave voltammetry (SWV) in 0.2 mol/L acetic acid buffer at pH 5.5. The result showed that the GO/TiO2-CuTCPP/GCE exhibits the higher peak current and photo-catalytic activity to prone the self-cleaning ability. Under the optimal conditions, the oxidation current peak values linearly with the concentration of 4-NP ranging from 0.5 to 100 μmol/L, and the detection limit was 0.16 μmol/L (S/N = 3). Moreover, the sensors showed excellent renewable ability under visible light without damaging the electrode microstructure and attenuating electrochemical signals.