Conductive nitrogen-doped carbon nanosheet-encapsulates bismuth nanoparticles for simultaneous high-performance detection of Cd(II) and Pb(II)

Cadmium (Cd) and lead (Pb) are two of the most toxic heavy metals, which cause serious pollution to the environment. It is of great significance to develop electrochemical sensing platforms that can be used for the efficient and simultaneous detection of Cd(II) and Pb(II). Herein, bismuth nanoparticles encapsulated in nitrogen-doped carbon nanosheets (Bi@NC) were successfully synthesized. An electrochemical sensor based on Bi@NC was proposed for the high-performance determination of trace Cd(II) and Pb(II). Encapsulated and uniformly distributed Bi nanoparticles with abundant active sites form alloys with Cd(II) and Pb(II), and the conductive nitrogen-doped carbon nanosheet accelerates the electron transport rate, thus the electrochemical signals of Cd(II) and Pb(II) are significantly amplified. Under optimized conditions, Cd(II) and Pb(II) can be simultaneously detected in concentrations ranging from 1 to 150 μg L −1 , with sensitivity of 0.48 μA μg −1 L and 0.36 μA μg −1 L, respectively. Meanwhile, the sensor possesses the outstanding advantages of ultra-high sensitivity, excellent selectivity, and storage stability, being able to serve as an electrochemical platform for Cd(II) and Pb(II) sensing in fruit and river water.