Figure 1.
The prepared Ag3PO4 nanoparticles.
a) XRD pattern and b) TEM image, the standard pattern of cubic Ag3PO4 with JCPDS No. 06-0505 is also shown for comparison.
Figure 2.
The oxidation reaction of TMB.
Figure 3.
UV-vis spectrum of the reaction system with H2O2 + Ag3PO4 nanocrystals.
The inset shows images of oxidation color reaction of TMB in NaAc buffer with a) H2O2, b) Ag3PO4 nanocrystals and c) H2O2 + Ag3PO4 nanocrystals. Reaction conditions: 0.3 mM of TMB, 2 mg/mL of Ag3PO4 (if with), 3.6 mM of H2O2 (if with) in 5 mL of NaAc buffer with pH 4.0. The reaction proceeded at 25°C with time of 30 min.
Figure 4.
pH value-dependent peroxidase-like catalytic activity of Ag3PO4 nanocrystals.
Reaction conditions: 0.3 mM of TMB, 2 mg/mL of Ag3PO4, 3.6 mM of H2O2 in 5 mL of NaAc buffer with different pH values. The reaction proceeded at 25°C with time of 30 min.
Figure 5.
H2O2 concentration dependent peroxidase-like catalytic activity of Ag3PO4 nanocrystals.
Reaction conditions: 0.3 mM of TMB, 2 mg/mL of Ag3PO4 in 5 mL of NaAc buffer with pH 4.0. The concentration of H2O2 varies in the range of 0.36–7.2 mM. The reaction proceeded at 25°C with time of 30 min.
Figure 6.
Steady-state kinetic assay of the Ag3PO4 nanocrystals.
a) The concentration of H2O2 was 5 mM and the TMB concentration was varied. b) Double reciprocal plots of 1/V ∼1/CTMB. Reaction conditions: 2 mg/mL of Ag3PO4 in 5 mL of NaAc buffer with pH 4.0 at 25°C.
Figure 7.
Time-dependent catalytic activity with a) different amounts of Ag3PO4 nanocrystals at 25°C and b) at different temperature with 4 mg/mL of Ag3PO4 nanocrystals.
Reaction conditions: 0.3 mM of TMB, 0–4 mg/mL of Ag3PO4, 3.6 mM of H2O2 in 5 mL of NaAc buffer with pH of 4. c) Control experiment to show the time-dependent absorption spectra of Ag3PO4 nanocrystals dispersed in buffer solution (pH = 4) at different concentrations (1, 2, 4 mg/mL).