Photocatalytically induced Au/mpg-C3N4 nanocomposites for robust electrochemical detection of Cr(VI) in tannery wastewater

Chromium readily undergoes redox speciation, and Cr(VI) oxidation state is ubiquitous and mobile in the environment. Under physiological conditions, Cr(VI) reduction yields species as Cr(V) or Cr(VI), which shows reactivity towards DNA damaging. Therefore, accurate detection of Cr species in the environmental compartment is of utmost importance. In compliance with green chemistry, Au/mpg-C 3 N 4 nanocomposites were successfully fabricated by ultra-violet photo-reduction without a reducing agent. The Au/mpg-C 3 N 4 nanocomposites were characterized by scanning electron microscope (SEM), X-ray diffractometry (XRD), X-ray photoelectron spectrometry (XPS), and infrared spectrophotometry. Well-dispersed gold nanoparticles with an average diameter of 50 nm decorated on mpg-C 3 N 4 . We developed a method to determine Cr(VI) with excellent sensitivity (0.002196 μA/ppb) and detection limit (14.7 ppb) using Au/mpg-C 3 N 4 modified glassy carbon working electrode by linear sweep voltammetry (LSV). The same electrode can use in real-time Cr(VI) monitoring using amperometry. The new sensor is stable and free from interferences from other species in natural water, and it can also be used in real-time Cr(VI) monitoring over wide concentration ranges.