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

Two-dimensional (2D) nanomaterials with catalytic activity have attracted considerable attentions from researchers, but their application in the detection of hazardous substances need to be further expanded. Herein, the layered tungsten sulfide (WS2) nanosheets with peroxidase-mimicking activity were firstly 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 atoms transfer (HAT) to form the yellow product of 2,3-diaminophenazine. Acetone can block the HAT from OPD to ·OH, thus cause the obvious inhibition of the peroxidase activity of WS2 nanosheets, making the solution exhibits pale yellow or even colorless. The investigation of catalytic kinetic indicates that the catalytic reaction was consisted with the "ping pong" mechanism, and the regulatory effect of acetone on WS2 nanosheets was confirmed to be an irreversible inhibition manner. The chemosensor can easily distinguish a trace amount of acetone by the naked eyes in less than 20 min, and has the limit of detection (LOD) for acetone 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 will play a bright perspective in acetone detection.