Coral-shaped tin oxide incorporated graphitic carbon nitride nanosheets as peroxidase mimic for sensitive colorimetric and fluorescence quenching based detection of hydrogen peroxide

The enhanced peroxidase-like catalytic activity of coral-shaped graphitic carbon nitride (GCN) incorporated with tin oxide (SnO2) is here reported and applied for the sensitive and selective colorimetric detection of hydrogen peroxide (H2O2). The SnO2/GCN catalyzed the oxidation of 3, 3 ', 5, 5 '-tetramethylbenzidine, and H2O2 which resulted in the appearance/change of color in the visible range. The results of peroxidase-like activity showed that the growth of SnO2 on GCN nanosheets improved structure, optical, and electronic properties considerably. SnO2/GCN-40% showed the best activity because of the optimal loading of SnO2, unique structural, electronic, optical, and electrical properties. The catalytic reaction of coral-shaped SnO2/GCN-40% followed the typical Michaelis-Menten equation, and the affinity of coral-shaped SnO2/GCN-40% to TMB and H2O2 was higher than that of horseradish peroxide. The present study showed a rapid, selective, and sensitive response toward the H2O2 bioassay in a linear range of 10 - 655 mu M with a limit of detection of 0.3 mu M (S/N ratio of 3). The study may provide a promising method of performance improvement for applications in catalysis, biosensors, and nanomaterial-engineering fields.