Moreover, the non-aggregation of nanoparticles in the reused catalyst further confirmed the stability of the prepared catalysts.
The optimum catalytic activity of was obtained when 4.6 × 10 −3 mM HAuCl 4 was used, which led to the complete reduction of 4-nitrophenol within 16 minutes with excellent recyclability for more than 5 catalytic cycles, giving yields over 94%. It is noteworthy that the red-shifted LSPR peaks of Au nanoparticles produced with increasing concentrations of HAuCl 4 indicated an increase in the particle size of the Au nanoparticles as justified by TEM images. The microstructural and morphological features of COPN-1 and were characterized in detail using FT-IR, C-NMR, elemental analysis, UV-Vis, XRD, TEM, BET, and TGA. Synthesized novel COPN-1 was mixed with different concentrations of HAuCl 4 which resulted in with varying sizes of Au nanoparticles in a controlled manner.
Herein, a simple synthetic route was applied to generate hybrids via in situ reduction of gold ions with no additional reducing agent. Covalent-organic polymer networks (COPNs) have been used as catalyst supports due to their stable and favorable structure.