Bimetallic metal–organic framework derived FeOx/TiO2 embedded in mesoporous carbon nanocomposite for the sensitive electrochemical detection of 4-nitrophenol

Abstract

A series of composites comprising FeOx and TiO2 nanoparticles uniformly distributed throughout a mesoporous carbon matrix (hereafter denoted as FeOx/TiO2@mC nanocomposites) was synthesized by the direct pyrolysis of a bimetallic Fe/Ti-based metal–organic framework at high temperatures (500, 700, and 900 °C). It shows that the as-prepared FeOx/TiO2@mC nanocomposites exhibit large specific surface areas and hierarchically micro/mesoporous hybrid structures, further leading to high electron transfer rate. Combining the highly electrocatalytic activity of TiO2 and FeOx and the good charge-transfer capability of mesoporous carbon, the caused synergism enables the construction of novel and platforms for sensitively detecting 4-nitrophenol (4-NP). After the optimization of sensitive layers and detection conditions, FeOx/TiO2@mC700 (calcined at 700 °C) is found to exhibit high detection ability toward 4-NP owing to its excellent electrochemical performance and electrocatalytic activity. The FeOx/TiO2@mC700-based electrochemical sensor shows a low limit of detection of 0.183 μM (S/N = 3) within the linear range of 5–310 μM as determined using amperometry toward 4-NP. The proposed method also displays good anti-interference ability, stability, and applicability toward 4-NP determination in environmental water samples. All these results suggest that the components of the MOF-derived binary metal oxide/mesoporous carbon electrocatalyst can function as a novel electrocatalyst for more endeavors into the development of a promising sensing platform for hazardous compounds in the environment.