Hybrid Boron Nitride/N-Doped Graphene Quantum Dots for Specific and Picomolar Electrochemical Detection of Pb(II) Ions

The growth in various industrial and economic sectors has led to the pollution of the world’s water resources to a considerable extent. Many harmful contaminants enter water sources consistently, leading to environmental damage, a major concern. One of the widespread pollutants are heavy metal ions (HMIs), such as ions of lead, mercury, cadmium, and arsenic, which are highly toxic even at very low concentrations of parts per billion (ppb) levels; they pose severe threats to both humans and other living organisms. This has headed to the stage where a constant monitoring system of environmental water resources for HMIs has become imperative. In this study, we have made a hybrid quantum dot material made of boron nitride (BN) and nitrogen-doped graphene (Hyb-BNQD-NGQD) from bulk BN and polyaniline (PANI), which exhibited specific sensing of Pb(II) ions. This material exhibited exceptional selectivity and sensitivity toward Pb(II) ions and a higher current response than the unmodified glassy carbon electrode, BNQDs, NGQDs, and the physical mixture of BNQDs and NGQDs with a remarkable detection limit of 1 × 10–12 M (0.2 ppt). Hyb-BNQD-NGQD exhibited selectivity for Pb(II) ions in the presence of multiple other potential interfering metal ions and maintained a similar current response (≤5% variation) in wastewater samples without any interference from other contaminants, highlighting its remarkable specific sensing capability.