was plotted against time rxn t with 0 A as a fitting parameter (Figure ). It is worth noting here that 0 A signifies the final value of  that is expected to be attained after a very long time. The plots in Fig. show that the data indeed followed this scaling, with the slope yielding the reaction rate constant, k . For generation of AgNPs and AuNPs, rate constant, k were found to be, Ag ~0.25 0.05 k  hr -1 (Figure ) and Au ~0.38 0.05 k  hr -1 respectively.