Enhanced Peroxidase-Like Activity of MoS(2) Quantum Dots Functionalized g-C(3)N(4) Nanosheets towards Colorimetric Detection of H(2)O(2)

MoS(2) quantum dots (QDs) functionalized g-C(3)N(4) nanosheets (MoS(2)@CNNS) were prepared through a protonation-assisted ion exchange method, which were developed as a highly efficient biomimetic catalyst. Structural analysis revealed that uniformly-dispersed MoS(2) QDs with controllable size and different loading amount grew in-situ on the surface of CNNS, forming close-contact MoS(2)@CNNS nanostructures and exhibiting distinct surface properties. Compared to MoS(2) QDs and CNNS, the MoS(2)@CNNS nanocomposites exhibited a more than four times stronger peroxidase-like catalytic activity, which could catalyze the oxidation of 3,3’,5,5’-tetramethylbenzidine (TMB) in the presence of H(2)O(2) to generate a blue oxide. Among the MoS(2)@CNNS nanocomposites, MoS(2)@CNNS(30) was verified to present the best intrinsic peroxidase-like performance, which could be attributed to the more negative potential and larger specific surface area. A simple, rapid and ultrasensitive system for colorimetric detection of H(2)O(2) was thus successfully established based on MoS(2)@CNNS, displaying nice selectivity, reusability, and stability. The detection limit of H(2)O(2) could reach as low as 0.02 μM. Furthermore, the kinetic and active species trapping experiments indicated the peroxidase-like catalytic mechanism of MoS(2)@CNNS. This work develops a novel, rapid, and ultrasensitive approach for visual assay of H(2)O(2), which has a potential application prospect on clinical diagnosis and biomedical analysis.