The Effect of g-C3N4 Materials on Pb(II) and Cd(II) Detection Using Disposable Screen-Printed Sensors

The disposable electrochemical sensors were designed and fabricated onto a photo paper substrate in-house. We report a first case use of g-C3N4, which is an emerging material as the most stable carbon-like polymer, explored for application as the electrochemical sensor on heavy metal ion detection. In this work, Bi/g-C3N4 materials were coated on the sensors using the drop-coating method. Pb(II) and Cd(II) were used as representative ions for this study. On the Bi/g-C3N4 (50:50 wt%)-coated sensor, the limit of detection (LOD) values of Cd (II) in buffer solution were 17.5 μg L−1 and 8.1 μg L−1 for Pb(II). For Bi nanoparticle–coated sensor, the LOD values of Cd(II) and Pb(II) in buffer solution were 21.8 and 10.4 μg L−1, respectively. From the water sample analysis, the Bi/g-C3N4-coated sensor illustrated slightly better responses for Cd(II) and Pb(II) in spiked tap water without pH adjustment compared to spiked tap water with pH adjustment. The results suggested that Bi/g-C3N4 is a functional detection material for Cd(II) and Pb(II) in water without pre-processes required. On the other hand, g-C3N4 materials are easily synthesized and scaled up with lower cost to that of Bi nanoparticles.