Sustainable capping of nanoscale copper particles with secondary metabolites of Hyptis capitata leaves for the catalytic degradation of pollutants and removal of bacteria from hydrous systems.

A green chemistry approach for the preparation of copper nanoparticles (CuNPs) using leaf extract of Hyptis capitata has been discussed. The presence of polyphenolic compounds and flavonoids in this plant was already confirmed and communicated by former researchers in their phytochemical studies. These biomolecules are efficient reducing and capping agents. After the successful synthesis, the CuNPs were characterized by UV-visible spectroscopy, FT-IR, XRD, HR-TEM, EDX, DLS, Zeta potential analyzer, and TGA techniques. The optical and morphological properties of CuNPs were elucidated using these characterization analyses. The average crystal size was found to be 12 nm. The characteristic SPR peak of CuNPs was obtained at 222.5 nm in the UV-visible absorption spectrum. CuNPs capped with HC leaf extract have the potential for catalytic transformation of pollutants methyl orange dye and 4-nitro phenol in aqueous system. Phytochemically stabilized CuNPs can inhibit the growth of gram-positive and gram-negative bacteria.