Two-dimensional layered WS₂ nanosheets as peroxidase mimetics in a colorimetric chemosensor for simple and rapid...

Two-dimensional (2D) nanomaterials with catalytic activity have attracted considerable attention from researchers, but their application in the detection of hazardous substances needs to be further expanded. Herein, layered tungsten sulfide (WS₂) nanosheets with peroxidase-mimicking activity were used to construct a colorimetric chemosensor for rapid detection of acetone. WS₂ nanosheets can decompose H₂O₂ to generate hydroxyl radicals (·OH), which will further oxidize o-phenylenediamine (OPD) through hydrogen atom transfer (HAT) to form the yellow product 2,3-diaminophenazine. Acetone can block the HAT from OPD to ·OH, thus causing obvious inhibition of the peroxidase activity of WS₂ nanosheets, making the solution appear pale yellow or even colorless. The investigation of catalytic kinetics indicates that the catalytic reaction consists of the 'ping pong' mechanism, and the regulatory effect of acetone on WS₂ nanosheets is confirmed to be an irreversible inhibition. The chemosensor can easily distinguish a trace amount of acetone by the naked eye in less than 20 min, and has a limit of detection for acetone of as low as 3.08 mg  l^-1. The application in actual samples displays the accuracy and stability of the chemosensor, suggesting that such a method is promising for acetone detection.