Tailoring porous NiMoO₄ nanotube via MoO₃ nanorod precursor for environmental monitoring: Electrochemical detection of micro-sized polyvinylchloride

Globally, the hidden contaminants like microplastics (MPs) combined with other harmful substances have agglomerated in rivers and oceans that pose a threat to human health. Thus, evaluating the toxicity of MPs separately and in combination with other pollutants must be done quickly and precisely. This work reports the synthesis of porous NiMoO₄ nanotubes (NTs) from the transformation of MoO₃ nanorods (NRs) via two steps hydrothermal methods for the effective detection of polyvinyl chloride (PVC) MPs. Transformation of MoO₃ NRs to porous NiMoO₄ NTs was comprehensively deduced by evaluating the crystalline, structural, compositional and morphological properties. The hydrophobic nature of MoO₃ NRs and porous NiMoO₄ NTs was proven experimentally and also by DFT calculations. The electrochemical detection of PVC MPs by NiMoO₄ NTs was investigated by the CV and EIS measurements. Porous NiMoO₄ NTs based electrode expressed the good detection towards PVC MPs with a reasonable sensitivity of ∼1.43 × 10⁻⁴ μA/ppm.cm², a low LOD of ∼18 ppm and R₂ = ∼0.9781. EIS results revealed that porous NiMoO₄ NTs electrode enabled to deliver sensing response at very low concentration of PVC MPs. Due to their easy interaction with hydrophobic PVC MPs, the hydrophobic NiMoO₄ NTs controlled the sensing nature of the material and improved the electrochemical detection at the MP-NiMiO₄ NTs interface.