Molybdenum trioxide embedded graphitic carbon nitride sheets modified electrode for caffeine sensing in green tea and coffee powder

The development of a screen-printed electrochemical sensor based on molybdenum trioxide (MoO3) grown on
the graphitic carbon nitride sheets (GCNS) nanocomposite was investigated for its ability to serve as an extremely
sensitive and selective sensor towards caffeine (CAF). The MoO3@GCNS nanocomposite was synthesized through
a simple hydrothermal method and was analyzed using spectroscopic and microscopic techniques (XPS, FT-IR,
and FE-SEM). Voltammetry outcomes illustrated the enhancement of electrocatalytic oxidation of CAF at
MoO3@GCNS modified electrode with higher oxidation current and also significantly reduced oxidation potential because of the synergetic effect between MoO3 and GCNS as compared to pure MoO3 and GCNS modified electrode. DPV results of MoO3@GCNS modified electrode displayed two wide straight lines (ranges of 0.5–359 μM and 410–810 μM) with a limit of detection of 21.24 nM with appreciable selectivity of 11.584 μA μM− 1 cm− 2 for CAF sensing. The modified electrode was further used for the detection of CAF in green tea and coffee powder samples.