Electrochemical performance of Ti3C2Tx MXene in aqueous media: towards ultrasensitive H2O2 sensing

•electrochemical characterization of MXene and oxidized MXene modified GCE.•characterization MXene and oxidized MXene modified GCE by other optical methods.•preparation of MXene and oxidized MXene modified GCE for detection of O2, NADH and H2O2.•proposed mechanism for electrochemical instability of MXene at a positive potential window.•construction of an ultrasensitive H2O2 sensor with LOD of 0.7 nM and a response time of 10 s.

An extensive characterization of pristine and oxidized Ti3C2Tx (T: O, OH, F) MXene showed that exposure of MXene to an anodic potential in the aqueous solution oxidizes the nanomaterial forming TiO2 layer or TiO2 domains with subsequent TiO2 dissolution by F− ions, making the resulting nanomaterial less electrochemically active compared to the pristine Ti3C2Tx. The Ti3C2Tx could be thus applied for electrochemical reactions in a cathodic potential window i.e. for ultrasensitive detection of H2O2 down to nM level with a response time of ∼10 s. The manuscript also shows electrochemical behavior of Ti3C2Tx modified electrode towards oxidation of NADH and towards oxygen reduction reactions.

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