Carbon nanotubes decorated with silver nanoparticles by a facile method, and their electrochemical and catalytic evaluation

In this work, MWCNTs were dispersed using the Hamelia patens plant extract and then decorated with AgNPs synthesized with the same aqueous extract as a reducing agent. The UV–Vis technique evaluates the products as a catalyst in the degradation of methylene blue dye during four repetition cycles. SEM, TEM, XRD, FTIR, and UV–Vis studied the products' size, structure, and morphology. SEM studies show MWCNTs successfully dispersed employing the stabilizing agents present in the Hamelia patens aqueous extract. Also, SEM and UV–Vis studies showed synthesized AgNPs and homogeneously dispersed on MWCNTs using Hamelia patens aqueous extract. XRD studies identified the mixture of Ag-cubic and C-hexagonal phases. At the same time, Raman spectroscopy determines MWCNTs structural defects caused by the AgNPs decoration. TEM illustrates AgNPs decorated on the MWCNTs surface with two average particle sizes attributed to Ostwald ripening. MWCNTs with smaller diameters are better decorated than those with larger diameters. HRTEM images illustrated that smaller AgNPs cause better surface decoration regardless of MWCNTs diameter. The CV technique shows that the MWCNTs decoration substantially improves the transport of electrons in the material. Finally, the AgNPs/MWCNTs showed a degradation efficiency of 86% for methylene blue in the first cycle and 44% after four cycles.