Highly electroactive mixed-valence-MoO_X as an electrochemical sensing for effective detection of p-nitrophenol based on the synergistic effect of valence change and oxygen vacancy

Transition metal oxides (TMOs) can effectively improve the performance of electrochemical detection due to their unique electronic structure and redox properties. However, the lack of reproducibility and the electrical activity of TMOs prepared from conventional preparation methods limit their further development. In this work, amorphous MoO_X with reductive Mo(V) was successfully synthesized by one-step electrodeposition, and it has excellent detection performance for p-nitrophenol (PNP). In general, the prepared amorphous mixed-valence MoO_X has rich reductive Mo(V), which produces valence change and accelerates electron transfer during detection. Moreover, the prepared material contains considerable oxygen vacancy, which remarkably enhances the adsorption process and redox of PNP. Through the synergistic effect of valence state transformation and oxygen vacancy, the catalytic redox of PNP is expedited. The sensitivity of the prepared MoO_X modified electrode to PNP was 0.5266 μA μM^-1, and the low detection limit was 0.0196 μM. MoO_X also shows good anti-interference, stability and reproducibility. On this basis, we can further optimize the electrodeposition process to prepare transition metal oxides with excellent catalytic properties in the future, and promote its wide application in the field of environmental monitoring and sensing.