Microwave-assisted Synthesis, Characterization, Photocatalytic Degradation of Antibiotics, and Fluorometric Selective Sensing Activity of g-CN Supported CuO Composites.

Herein, we have designed for the fabrication of a series of g-CN/CuO composite by using one-step microwave-assisted synthesis for the degradation of antibiotics and detection of nano-molar range of toxic heavy metal ions. The synthesized g-CN/CuO composites were analyzed and characterized to know the structure, phase, surface area, absorption region, bandgap, and size of the composites. From the observation of TEM and XRD measurements, g-CN/CuO composites have hexagonal shape with average diameter of the particles is 25 ± 5 nm. The observed band gap values from UV-vis DRS for g-CN nanosheets and CuO NPs are 2.64 eV and 1.72 eV. The synthesized g-CN/CuO composite has prodigious specific surface area (32.47 m/g), which is the evident for superior heterogeneous catalytic applications. Therefore, the synthesized g-CN/CuO composites were tested for the degradation of antibiotics such as tetracycline (TC) and ciprofloxacin (CIP) under UV light illumination, it shows 88.02% and 90.01% degradation was observed within 1 h due to the matching optical band gap and internal charge transfer of excitons with in the heterojunction surface among g-CN and CuO in the composite than the individual components (g-CN and CuO) due to the high surface area and tiny particles of CuO were randomly deposited on the surface of g-CN nanosheets. The catalytic reduction reaction follows as pseudo-first order equation and reused for 5 consecutive cycles without remarkable loss of catalytic activity. Moreover, the synthesized CuO NPs and g-CN/CuO composites were used as a prominent fluorescence sensing probe for the selective detection of Pb in nano-molar range of concentration with K is 1.38 × 10 moldm. It was observed as a linear relationship based on the change in intensity, the limit of detection was determined to be 0.184 nM.