Cubic Cu2O-decorated B-doped g-C3N4 nanosheets for ultrasensitive electrochemical detection of Metol

초록

Pharmaceutical residues in environmental waters pose a significant threat to ecosystems and human health, necessitating the development of reliable and sensitive detection platforms. In this study, we report the fabrication of an ultrasensitive electrochemical sensor based on a Cu2O/boron-doped graphitic carbon nitride (Cu2O/B-g-C3N4) nanocomposite for the selective detection of Metol, a widely used but environmentally hazardous compound. The nanocomposite was synthesized via a simple sonication-assisted self-assembly process, forming a hybrid architecture in which well-defined cubic Cu2O nanocrystals were anchored onto thermally treated B-g-C3N4 nanosheets. Structural characterization (X-ray Diffraction XRD, X-ray Photoelectron Spectroscopy XPS, Scanning Electron Microscopy SEM, Transmission Electron Microscopy TEM) confirmed the successful formation of the hybrid nanostructure with intimate interfacial contact. The modified glassy carbon electrode (GCE) exhibited enhanced electrochemical response toward Metol, with a low detection limit of 0.677 nM and a broad linear range of 0.001-90 mu M. This excellent sensing performance arises from the synergistic effect of the heterojunction formed between Cu2O and B-g-C3N4, which promotes efficient charge separation, while boron doping introduces structural defects and enhances conductivity. Additionally, the doped g-C3N4 matrix provides Lewis acidic and pi-interaction sites, resulting in increased analyte affinity and improved redox sensitivity toward Metol. The sensor demonstrated excellent reproducibility (relative standard deviation RSD < 4.87 %) and recovery (96-99 %) in real samples, including human serum, urine, tap water, and wastewater. These results highlight the potential of Cu2O/B-g-C3N4 as a promising nanoplatform for trace-level detection of pharmaceutical pollutants in environmental and clinical matrices.

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