Superior conductivity FeSe2 for highly sensitive electrochemical detection of p-nitrophenol and o-nitrophenol based on synergistic effect of adsorption and catalysis

Accurate determination of highly toxic organic pollutants in the water environment is urgent for the protection of environment and human health. Nevertheless, the development of sensitive nanomaterials for p-nitrophenol (PNP) and o-nitrophenol (ONP) electroanalysis remains a big challenge due to the electrochemical redox inertness of organics, which requires the nanomaterials to own considerable catalytic performance. In this work, FeSe2 with high electronic conductivity and large active area was successfully prepared by hydrothermal synthesis and thermally induced selenization method. The results under the optimized conditions show that the FeSe2 modified electrode exhibits high sensitivity (0.397 and 0.377 μA μM−1) and low detection limit (0.030 and 0.036 μM) for PNP and ONP, respectively. Besides, the catalytic rate constant, diffusion coefficient and adsorption capacity determined by chronoamperometry and adsorption experiments are 4745.06 M−1 s−1, 2.98 × 10−4 cm2 s−1 and 5.81 mg g−1, respectively, which indicate that the impressive electrochemical behavior of the prepared electrode should attribute to the combined effect of adsorption and catalysis. Moreover, the constructed high-efficiency sensor exhibits superior selectivity, stability, reproducibility, and also realizes the electrochemical detection of organic pollutants in subsidence area water samples.