OICC Press Journal of Nanostructure in Chemistry 2193-8865 11 4 (December 2021) 2021 02 15 Coral-shaped tin oxide incorporated graphitic carbon nitride nanosheets as peroxidase mimic for sensitive colorimetric and fluorescence quenching based detection of hydrogen peroxide 10.1007/s40097-021-00392-y EN Aftab Ahmed Interdisciplinary Research Centre in Biomedical Materials (IRCBM), COMSATS University Islamabad, Lahore Campus, Lahore, Punjab, 54000, PK Government College University Lahore, Lahore, Punjab, 54000, PK Akhtar Hayat Interdisciplinary Research Centre in Biomedical Materials (IRCBM), COMSATS University Islamabad, Lahore Campus, Lahore, Punjab, 54000, PK Peter John Government College University Lahore, Lahore, Punjab, 54000, PK Mian Hasnain Nawaz Interdisciplinary Research Centre in Biomedical Materials (IRCBM), COMSATS University Islamabad, Lahore Campus, Lahore, Punjab, 54000, PK Muhammad Nasir Interdisciplinary Research Centre in Biomedical Materials (IRCBM), COMSATS University Islamabad, Lahore Campus, Lahore, Punjab, 54000, PK Journal Article 2021 02 15 Abstract The enhanced peroxidase-like catalytic activity of coral-shaped graphitic carbon nitride (GCN) incorporated with tin oxide (SnO 2 ) is here reported and applied for the sensitive and selective colorimetric detection of hydrogen peroxide (H 2 O 2 ). The SnO 2 /GCN catalyzed the oxidation of 3, 3′, 5, 5′-tetramethylbenzidine, and H 2 O 2 which resulted in the appearance/change of color in the visible range. The results of peroxidase-like activity showed that the growth of SnO 2 on GCN nanosheets improved structure, optical, and electronic properties considerably. SnO 2 /GCN-40% showed the best activity because of the optimal loading of SnO 2 , unique structural, electronic, optical, and electrical properties. The catalytic reaction of coral-shaped SnO 2 /GCN-40% followed the typical Michaelis–Menten equation, and the affinity of coral-shaped SnO 2 /GCN-40% to TMB and H 2 O 2 was higher than that of horseradish peroxide. The present study showed a rapid, selective, and sensitive response toward the H 2 O 2 bioassay in a linear range of 10 − 655 μM with a limit of detection of 0.3 μM (S/N ratio of 3). The study may provide a promising method of performance improvement for applications in catalysis, biosensors, and nanomaterial-engineering fields. Graphical abstract Scheme shows the interaction of tin oxide with graphitic carbon nitride which resulted in a coral-shaped structure shown in SEM image. It also shows the interaction of tin oxide and graphitic carbon nitride with H 2 O 2 in the presence of TMB (3,3′, 5,5′-Tetramethylbenzidine) and as a consequence, TMB gets oxidized and ended up in change in color.