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Graphitic Carbon Nitride Sensitized with CdS Quantum Dots for Visible-Light-Driven Photoelectrochemical Aptasensing
Yong Liu1, Kai Yan1, Jingdong Zhang1
1Key Laboratory for Large-Format Battery Materials and System (Ministry of Education), School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology , Luoyu Road 1037, Wuhan 430074, P. R. China.
Abstract:
Graphitic carbon nitride (g-C3N4) is a new type of metal-free semiconducting material with promising applications in photocatalytic and photoelectrochemical (PEC) devices. In the present work, g-C3N4 coupled with CdS quantum dots (QDs) was synthesized and served as highly efficient photoactive species in a PEC sensor. The surface morphological analysis showed that CdS QDs with a size of ca. 4 nm were grafted on the surface of g-C3N4 with closely contacted interfaces. The UV-visible diffuse reflection spectra (DRS) indicated that the absorption of g-C3N4 in the visible region was enhanced by CdS QDs. As a result, g-C3N4-CdS nanocomposites demonstrated higher PEC activity as compared with either pristine g-C3N4 or CdS QDs. When g-C3N4-CdS nanocomposites were utilized as transducer and tetracycline (TET)-binding aptamer was immobilized as biorecognition element, a visible light-driven PEC aptasensing platform for TET determination was readily fabricated. The sensor showed a linear PEC response to TET in the concentration range from 10 to 250 nM with a detection limit (3S/N) of 5.3 nM. Thus, g-C3N4 sensitized with CdS QDs was successfully demonstrated as useful photoactive nanomaterials for developing a highly sensitive and selective PEC aptasensor.
