Fig. 4. (a) XRD pattern of synthesized copper nanoparticles obtained by Step 1 (yellow curve), obtained by Step 1 and 2 (red curve) and obtained by Step 3 (blue curve); (b) FTIR curve of pristine l-ascorbic (red curve), pristine PVP (blue curve) and synthesized copper nanoparticles (black curve); (c) TG curve of synthesized copper nanoparticles (black curve), pristine l-ascorbic acid (red curve) and pristine PVP (blue curve).