Facile syntheses of bimetallic Prussian blue analogues (KxM[Fe(CN)6]·nH2O, M=Ni, Co, and Mn) for electrochemical determination of toxic 2-nitrophenol

In this work, three kinds of bimetallic Prussian blue analogues (PBAs), i.e. K x Ni [Fe(CN) 6 ]·nH 2 O (NiFe-PBA), K x Co [Fe(CN) 6 ]·nH 2 O (CoFe-PBA), and K x Mn [Fe(CN) 6 ]·nH 2 O (MnFe-PBA), were synthesized by a simple precipitation method under identical conditions. Their chemical compositions , structures, morphologies, valences of transition metals, and electrochemical sensing performances for 2-nitrophenol (2-NP) are examined in details. It is found that all the prepared PBAs hold face-centered-cubic structures with near perfect cube morphologies for NiFe-PBA and CoFe-PBA and truncated cube morphology for MnFe-PBA. For the electrochemical detection of 2-NP, a wide detection range of 1.0–700.0 μM was obtained at all PBAs modified electrodes together with the sensitivities of 443.3, 368.0, and 339.0 μA cm −2  mM −1 and detection limits of 0.28, 0.46, and 0.59 μM achieved at NiFe-PBA, CoFe-PBA, and MnFe-PBA modified electrodes, respectively. The superiority in electrochemical sensing performance of NiFe-PBA to CoFe-PBA and MnFe-PBA may stem from its higher conductivity, lager electroactive surface area, and better intrinsic catalytic property of the transition metal in its framework. Furthermore, the constructed NiFe-PBA-based sensor displays good repeatability, long-term stability, and high selectivity together with desirable recoveries (97.8–103.9%) for the assay of 2-NP in water samples. The present work is the first report on the PBAs-based electrochemical sensors for 2-NP detection, which may promise a future of PBAs or PBAs-based materials for sensing applications.