Three-dimensional cobalt sulfide hollow nanocubes decorated two-dimensional molybdenum disulfide nanosheets towards peroxidase-mimetic nanozyme with enhanced catalysis activity for the colorimetric analysis of sulfide ions

An efficient hybrid nanozyme was synthesized through in-situ growing two-dimensional (2D) MoS 2 nanosheets (NSs) onto three-dimensional (3D) Co 1-x S nanocubes (NCs) by one-pot hydrothermal method. This novel heterostructure was found to exhibit much enhanced peroxidase-mimetic catalytic activities compared to pristine Co 1-x S NCs and MoS 2 NSs, due to the accelerated charge transfer facilitated by the 3D/2D interfacial coupling. The core mechanism underlying this enhancement involves synergistic interaction between Co 1-x S and MoS 2 , which promotes electron transfer and increases the generation of reactive oxygen species ( • OH radicals), thereby improving catalytic efficiency. Importantly, the catalytic activity of the Co 1-x S/MoS 2 hybrid nanozyme can be selectively inhibited by sulfide ions (S 2− ) due to competitive utilization of • OH radicals and reduction of oxidized TMB substrate by S 2− . As a result, an efficient catalysis-based colorimetric detection method was developed for S 2− analysis in environmental water samples. Profiting by the cooperative effect between two components as well as the accelerated electron transfer of as-prepared hybrid nanozyme, the developed colorimetric detection method can achieve a wider linear range (0.10–50 μM), a low limit of detection (LOD, 0.021 μM), and excellent recovery rates (98.3%–104.0%) in real water samples, highlighting its potential for practical applications in water safety assessment. This study provides a novel strategy for designing high-performance nanozymes with 3D/2D heterostructures for environmental sensing applications.