S doping strategy on Co3O4 nanosheets for enhanced electrochemical detection towards p-nitrophenol

Sensitive detection of organic pollutants in water environment remains a significant challenge in electroanalysis. Doping has emerged as an effective strategy for enhanced the electroanalytical performance of nanomaterials. In this study, a non-metalic element, sulfur (S), was doped into Co3O4 nanosheets via a simple hydrothermal method. Characterizations, including scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS), revealed that the S-doped Co3O4 (S-Co3O4) nanosheets retained their structural integrity, including phase and micromorphology. However, the oxygen vacancies and the Co2+/Co3+ ratio were higher in S-Co3O4 compared to pure Co3O4 nanosheets. After fabricating the S-Co3O4 as a sensing interface for detecting the organic toxic pollutant p-nitrophenol (PNP), the S-Co3O4 demonstrated superior detection performance with a high sensitivity of 0.3068 mu A mu M- 1 in the concentration range of 0-10 mu M PNP and a low limit of detection of 0.037 mu M. The enhanced detection capability of S-Co3O4 compared with Co3O4 nanosheets can be attributed to the addition of the S element. Furthermore, S-Co3O4 exhibited anti- interference ability, stability and applicability to real water samples, underscoring the significance of S doping in advancing electroanalysis techniques.