| Autor: |
Chaa, A., Haddad, A., Rekhila, G., Tria, S., Trari, M. |
| Zdroj: |
Journal of the Iranian Chemical Society; August 2024, Vol. 21 Issue: 8 p2113-2120, 8p |
| Abstrakt: |
The semiconducting properties of Mn3O4thin films were assessed for the heterogeneous photocatalytic oxidation of Rhodamine B (Rh B). The films were grown on Al-substrate using a spray coating, and their physical and photoelectrochemical characteristics were studied. X-ray diffraction analysis showed a well-crystallized structure of the spinel Mn3O4. The atomic force microscopy revealed dense and irregular grains with a mean size of ~ 50 nm and a thickness of ~ 1 µm. The direct optical transition at 2.19 eV, in agreement with the brown color, is assigned to d–dtransitions within the incomplete Mn-3dshell, which enables efficient photocatalytic conversion of the solar radiation. The photoelectrochemical measurements demonstrated p-type comportment, evidenced by a negative slope in the [capacitance−2–potential: C−2–E] graph with a flat band potential of + 0.35 VSCEand a hole density of 6.5 × 1018cm−3. The electrochemical impedance spectroscopy (EIS) plot showed a semicircle due to a capacitive comportment of the bulk spinel (Rb= 70 kΩ cm2). The center positioned below the abscissa axis (− 23°) with a constant phase element (CPE). The conduction band (− 1.64 VSCE) is more cathodic than the O2/O2∙-level, thus catalyzing the photocatalytic process by O2∙-radicals. Under sunlight, 50% reduction of the Rh B concentration (10 ppm) was achieved within 1 h, the color removal, followed by spectrophotometry obeys a pseudo-first-order kinetic model with a rate constant of 9.9 × 10–3min−1(t1/2= 70 min). |
| Databáze: |
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