Table 2 Induction time and rate constant of the 4-NP reduction reaction in the presence of either CA-AuNPs or cf-CA-AuNPs
From: Catalytic reduction of 4-nitrophenol with gold nanoparticles synthesized by caffeic acid
Caffeic acid final concentrations | 0.08 mM | 0.12 mM | 0.16 mM | 0.20 mM | 0.24 mM | 0.28 mM | 0.32 mM | 0.36 mM | 0.40 mM | |
|---|---|---|---|---|---|---|---|---|---|---|
Induction time (s) | CA-AuNPs | 0 | 0 | 0 | 0 | 180 | 480 | 780 | 1080 | 1380 |
cf-CA-AuNPs | 0 | 0 | 0 | 0 | 0 | 0 | 300 | 300 | 780 | |
Rate constant (s−1) | CA-AuNPs | 2.63 × 10-3 | 1.53 × 10-3 | 1.26 × 10-3 | 0.86 × 10-3a | 0.49 × 10-3 | 0.72 × 10-3 | 0.51 × 10-3 | 0.44 × 10-3 | 0.33 × 10-3 |
cf-CA-AuNPs | 5.73 × 10-3 | 3.40 × 10-3 | 3.32 × 10-3 | 3.24 × 10-3 | 3.14 × 10-3 | 3.25 × 10-3 | 3.17 × 10-3 | 2.55 × 10-3 | 0.80 × 10-3 | |
Fold of increase | 2.18 | 2.22 | 2.63 | 3.77 | 6.41 | 4.51 | 6.21 | 5.80 | 2.42 | |