A colorimetric sensing platform for the determination of H 2 O 2 using 2D-1D MoS 2 -CNT nanozymes.

A novel colorimetric platform based on nano-composites of two-dimensional (2D) molybdenum disulfide nanosheets (MoS 2 NSs) and one-dimensional (1D) carbon nanotubes (CNTs), called 2D-1D MoS 2 -CNT nanozyme, was fabricated for the selective and sensitive determination of hydrogen peroxide (H 2 O 2 ) in soda water. The MoS 2 -CNT nanozyme was synthesized through a one-step solvothermal reduction method. The introduced CNTs could effectively prevent the stacking of MoS 2 nanosheets (NSs) and not only expanded the interlayer distance of MoS 2 NSs from 0.620 nm to 0.710 nm but also improved their specific surface. Under acidic conditions, the as-prepared 2D-1D MoS 2 -CNT nanozymes could oxidize the colorless 3,3',5,5'-tetramethylbenzidine (TMB) to blue-oxidized TMB (oxTMB) in the presence of H 2 O 2 , resulting in enhanced peroxidase-like (POD-like) activity. The kinetic study showed that MoS 2 -CNT nanozyme had stronger catalytic activity than natural horseradish peroxidase (HRP). The linear range for H 2 O 2 colorimetric determination was 5.00-500 μmol L -1 with a limit of detection (LOD) of 1.40 μmol L -1 . Furthermore, the established determination method was applied to actual samples and the recoveries of H 2 O 2 spiked in soda water were in the range of 92.3-107%, showing feasibility for the analysis of food.