A colorimetric sensing platform for the determination of H₂O₂ using 2D-1D MoS₂-CNT nanozymes

A novel colorimetric platform based on nano-composites of two-dimensional (2D) molybdenum disulfide nanosheets (MoS₂ NSs) and one-dimensional (1D) carbon nanotubes (CNTs), called 2D-1D MoS₂-CNT nanozyme, was fabricated for the selective and sensitive determination of hydrogen peroxide (H₂O₂) in soda water. The MoS₂-CNT nanozyme was synthesized through a one-step solvothermal reduction method. The introduced CNTs could effectively prevent the stacking of MoS₂ nanosheets (NSs) and not only expanded the interlayer distance of MoS₂ NSs from 0.620 nm to 0.710 nm but also improved their specific surface. Under acidic conditions, the as-prepared 2D-1D MoS₂-CNT nanozymes could oxidize the colorless 3,3',5,5'-tetramethylbenzidine (TMB) to blue-oxidized TMB (oxTMB) in the presence of H₂O₂, resulting in enhanced peroxidase-like (POD-like) activity. The kinetic study showed that MoS₂-CNT nanozyme had stronger catalytic activity than natural horseradish peroxidase (HRP). The linear range for H₂O₂ 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 H₂O₂ spiked in soda water were in the range of 92.3-107%, showing feasibility for the analysis of food.