An ultrasensitive label-free photoelectrochemical sensor based on Ag2O-sensitized WO3/TiO2 acicular composite for AFB1 detection

摘要

Tungsten trioxide (WO3) nanoplates (NPs) were modified on fluorine-doped SnO2 transparent conductive glass (FTO) electrodes by the wet chemical route, and oriented titanium dioxide (TiO2) nanoprickles were tightly and uniformly synthesized on the surface of WO3 by the chemical bath deposition (CBD) method to obtain the WO3/TiO2 composite. Thereafter, Ag2O nanoparticles were formed on the surface of the WO3/TiO2 composite by an in situ growth method. With glutathione (GSH) as the electron donor and visible-light excitation, the WO3/TiO2/Ag2O composite exhibited a worthwhile photoelectric signal, reaching about 56 mu A. Therefore, the label-free PEC sensor was successfully prepared for the supersensitive detection of aflatoxin B1 (AFB1). When the concentration of AFB1 was within 0.005-0.4 ng mL(-1), the photocurrents showed a linear downward trend with a detection limit of 1.67 pg mL(-1). Moreover, AFB1 was satisfactory in the selectivity tests involving zearalenone (ZEN), vomitoxin (DON), and ochratoxin A (OTA). Furthermore, the PEC sensor exhibited the characteristics of stability and good reproducibility, which has broad application prospects in the detection of other toxic small molecules as well as in the preparation of a photoelectric material.