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

Graphical abstract A novel electrochemical sensing strategy for detecting hazardous 4-nitrophenol (4-NP) was constructed based on mesoporous carbon embedded with FeO x and TiO 2 nanoparticles (denoted as FeO x /TiO 2 @mC nanocomposites) derived from the bimetallic Fe/Ti-based metal–organic framework at high temperature. The developed electrochemical sensor shows excellent sensitivity, good anti-interference ability, stability, and applicability toward 4-NP determination in environmental water samples. Highlights • Bimetallic Fe/Ti-based MOF derived mesoporous carbon embedded with FeO x and TiO 2 nanoparticles. • A hierarchically micro/mesoporous FeO x /TiO 2 @mC-based electrochemical sensor was constructed. • Excellent sensitivity, selectivity, stability, and applicability for detecting 4-nitrophenol. Abstract A series of composites comprising FeO x and TiO 2 nanoparticles uniformly distributed throughout a mesoporous carbon matrix (hereafter denoted as FeO x /TiO 2 @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 FeO x /TiO 2 @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 TiO 2 and FeO x 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, FeO x /TiO 2 @mC 700 (calcined at 700 °C) is found to exhibit high detection ability toward 4-NP owing to its excellent electrochemical performance and electrocatalytic activity. The FeO x /TiO 2 @mC 700 -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. [ABSTRACT FROM AUTHOR]