Covalent and non-covalent approach for SWCNT-containing macromolecular structure formation for palladium accumulation

In this study, novel materials combining palladium-imprinted polymers (PdIP) with single-walled carbon nanotubes (SWCNTs) were developed to modify screen-printed electrodes (SPEs) and tested as sensors for detecting palladium ions. The arrangement of the SWCNTs-PdIP network is crucial for the electrochemical performance of the material. Therefore, we compared two types of materials: one with covalent linkages and the other with non-covalent linkages between the SWCNTs and the polymer. The materials were characterized using Fourier transform infrared spectroscopy, Raman spectroscopy, thermogravimetric analysis, scanning electron microscopy, and porosimetry. Cyclic and differential pulse voltammetry demonstrated a significant improvement in the electrochemical properties of the material with covalent linkages between PdIP and SWCNTs. The results confirmed the performance of the proposed SWCNTs-X/PdIP-based electrochemical sensor for detecting palladium ions. They showed a linear relationship in the concentration range of 0.06–1.5 mmol L⁻¹, and the estimated limit of detection (LOD) was 0.026159 mmol L⁻¹ (S/N=3). The constructed sensor showed high analytical sensitivity (675.46 μA mmol⁻¹ L cm⁻²), good repeatability (RSD=4.05 %), and recovery (97 %).