Oxygen vacancies driven Pd - MoO₃ / f - MWCNTs nanocomposite for electrochemical sensing of Pb (II)

Metal oxide nanomaterials have faced challenges in detecting toxic metal ions (TMIs), primarily due to their limited conductivity and insufficient active sites. One effective approach is enhancing oxygen vacancies (OVs) and introduction of metal ions. In this work, we optimized OVs by incorporating varying mol% of palladium chloride during MoO₃ synthesis. This approach not only tunes OVs but also introduces Pd ions, modifying the bandgap, altering morphology, and improving reaction kinetics. Here, MoO₃ and Pd-MoO_3-x nanofibers were synthesized via a hydrothermal method, where Pd-MoO_3-x exhibited superior selectivity and sensitivity in the linear detection range of 0.1-1 ppm for Pb (II) compared to pure MoO₃. The enhanced sensing capability is attributed to increased active sites from OVs and Pd, boosting metal reactivity. Additionally, formation of nanocomposite using Pd-MoO_3-x with functionalized carbon nanotubes (f-MWCNTs) further improved electrochemical performance due to increased adsorption sites. This synergistic effect of OVs and Pd modification in the nanocomposite provides a promising strategy for high-performance electrode materials, advancing electrochemical sensing of TMIs.