A one-pot hydrothermal synthesis of graphene/CdS:Mn photocatalyst for photoelectrochemical sensing of glutathione

Abstract

A stable graphene (GR)/CdS:Mn photocatalyst was synthesized through a simple and straightforward one-pot hydrothermal method, and it exhibited enhanced photoelectrochemical (PEC) response to glutathione. The catalyst was characterized by X-ray diffraction, X-ray photoelectron spectroscopy, Raman spectroscopy and UV-vis diffuse reflectance spectroscopy. It showed efficient separation of photogenerated charge carriers and low photo-corrosion. The doped Mn²⁺ effectively improved the band structure of CdS. Meanwhile, the introduced GR greatly enhanced and facilitated visible light absorption as well as electron transport. The GR/CdS:Mn based PEC sensor displayed more sensitive photocurrent response to glutathione than the pure CdS, CdS:Mn and GR/CdS based sensors. Furthermore, the response of the sensor was rapid and stable. The details of the additions and specific effects of each component were discussed. Under the optimized conditions, it presented wide detection range of 0.01 μM to 100 μM, low detection limit, as well as good reproducibility. The sensor could be applied to the determination of glutathione in tomato and ketchup samples.