Facile Synthesis of Protonated Carbon Nitride/Ti ₃ C ₂ T _x Nanocomposite for Simultaneous Detection of Pb ²⁺ and Cd ²⁺

A high-sensitivity electrochemical sensor for heavy metal ions (HMIs) was prepared by associating Ti ₃ C ₂ T _x with protonated carbon nitride (H–C ₃ N ₄ /Ti ₃ C ₂ T _x ). Due to the electrostatic interaction, massive H–C ₃ N ₄ was distributed on the surface of Ti ₃ C ₂ T _x and served as coating material. H–C ₃ N ₄ /Ti ₃ C ₂ T _x composite showed great conductivity derived from Ti ₃ C ₂ T _x , and H-C ₃ N ₄ was with abundant electroactive deposition sites for the deposition of HMIs. In addition, the stability of H–C ₃ N ₄ /Ti ₃ C ₂ T _x composite was enhanced due to the protective H–C ₃ N ₄ coating. The H–C ₃ N ₄ /Ti ₃ C ₂ T _x electrode exhibited remarkable sensitivities for the simultaneous detection of Cd ²⁺ (0.05 ∼ 1.50 μ M) and Pb ²⁺ (0.05 ∼ 1.50 μ M) and the detection limit of Cd ²⁺ and Pb ²⁺ were 0.001 and 0.0006 _{} μ M, respectively. Notably, sensor based on H–C ₃ N ₄ /Ti ₃ C ₂ T _x composite showed excellent selectivity for Cd ²⁺ and Pb ²⁺ in the presence of interfere ions and molecules (K ⁺ , Na ⁺ , Ca ²⁺ , Hg ²⁺ , Cr ²⁺ , Cu ²⁺ , Cl ⁻ , NO ₃ ⁻ , PO ₄ ⁻ , ascorbic acid, uric acid, acetaminophen, glucose and nicotinamide). Besides that, distinguished stability and reproductivity of H–C ₃ N ₄ /Ti ₃ C ₂ T _x electrode indicate that this sensor is promising for HMIs in wastewater and other commercial applications.