ZnO-NRs embedded guar-gum derived CS@HNTs: A bifunctional catalyst for electrochemical detection and photocatalytic applications

Natural clay minerals and their nanocomposites are being increasingly studied for environmental remediation applications because of their abundance and unique surface properties. Halloysite nanotubes (HNTs) were modified with carbon spheres derived from guar gum through hydrothermal treatment, resulting in CS@HNTs. ZnO nanorods (ZnO-NRs) were synthesized via a sol-gel process and then loaded onto CS@HNTs, which enhanced their photocatalytic and electrochemical activities by widening their band structure and light absorption capabilities. The physicochemical and optoelectronic properties of the resulting CS@HNTs/ZnO-NRs nanocomposite was confirmed. The electrochemical detection of CPZ in the presence of CS@HNTs/ZnO/SPCE nanocomposite resulted in an excellent detection limit (LOD = 0.01 µM), sensitivity (1.917 µAµM–1 cm–2), and a wide linear range of detection (0.08–83.56 µM). Photocatalytic experiments were performed using the antibiotics tetracycline hydrochloride (TC) and CPZ under simulated solar irradiation. The degradation efficiency was 85.34 % and 83.84 %, respectively, due to the rapid charge carrier transport and reduced recombination. These findings demonstrate the excellent photocatalytic and electrocatalytic performance of the synthesized CS@HNTs/ZnO-NRs bifunctional catalyst.