High-valence Mo(VI) derived from in-situ oxidized MoS2 nanosheets enables enhanced electrochemical responses for nitrite measurements

Semiconducting MoS2 obtained from the liquid-phase exfoliation is oxidized at the potentials higher than 0.65 V via applied electrochemical processes, and high-valence Mo(VI) are formed. The oxidized MoS2 exhibits comparable performance to the electrochemical oxidation of nitrite, promoting the construction of sensors based on the assembly of nanomaterials. The signal amplification mechanism is exploited, and enhanced sensing responses are confirmed considering the strong coupling effect of Mo(VI) to nitrite. In order to optimize the sensing performance, the measurement parameters including the pH of buffer solutions, scan rates, and modification conditions are discussed. The cyclic voltammetry and chronoamperometry are successfully employed, and the oxidized MoS2 performs satisfactory linear relationship to nitrite concentrations ranging from 1.0 ?M to 386.0 ?M, with the detection limit of 0.028 ?M. The oxidation state and enhanced electrochemical responses of semiconducting MoS2 as well as the developed nitrite sensing strategy inspire emerging characteristics of layered nanostructures and achieve the high potential in practical environmental and food safety monitoring.

Automated summary

Semiconducting MoS2 is oxidized via electrochemical processes, forming high-valence Mo(VI) which exhibits comparable performance to nitrite oxidation for sensor construction. Enhanced sensing responses are achieved through signal amplification mechanism due to the strong coupling effect of Mo(VI) to nitrite. Measurement parameters such as pH, scan rates, and modification conditions are discussed for optimizing sensing performance, with satisfactory linear relationship and a detection limit established.