Oxidase-Like Catalytic Performance of Nano-MnO₂ and Its Potential Application for Metal Ions Detection in Water

Figure 9

UV-Vis differential absorbance spectra (DAS) calculated on the basis of the data recorded at different metal ion concentrations (0, 0.002, 0.01, 0.05, and 0.25 mmol·L⁻¹). Reaction conditions: Nano-MnO₂ = 0.1 mg·mL⁻¹; 2,6-DMP = 1.0 mmol·L⁻¹; metal ion = 0–0.25 mmol·L⁻¹. Error bars represent the standard deviation (n = 3). (a) Cu²⁺, (b) Zn²⁺, (c) Mn²⁺, and (d) Fe²⁺.

(a)

(b)

(c)

(d)