Abstract

MURILLO RUIZ, Edwin Alberto; RABA PAEZ, Ángela Mercedes  and  RINCON JOYA, Miryam. EFFECT OF THE CONCENTRATION OF IRON IN THE PROPERTIES OF Nb₂O₅ WITH POSSIBLE PHOTOCATALITIC APPLICATION. Cienc. Ing. Neogranad. [online]. 2018, vol.28, n.2, pp.29-43. ISSN 0124-8170.  https://doi.org/10.18359/rcin.2669.

At present, low band gap energy compounds are under development to be applied in photocatalysis. Niobium pentoxide was doped with iron to establish the relationship between its structural, surface and optical properties and its potential photocatalytic applications. Fe-doped Nb2O5 powders were prepared (at 2.5, 5 and 10 %, weight percent) using the Pechini method to create the appropriate synthesis conditions for the formation of Nb2O5:Fe particles. The powders were sintered at 600 and 700 °C for two hours in air and subsequently examined by TGA, XRD, SEM, UV-vis diffuse reflectance spectroscopy and the BET method. In pre-calcined samples, the thermal analysis allowed to establish the behavior of weight loss percentage dependent on temperature. Results obtained for non-doped oxide were compared with those of Fe-doped Nb2O5 to analyze its crystalline properties. The diffractograms of Fe-doped Nb2O5 at 2.5 and 5 %, subjected to 700 °C, were similar to those of non-doped Nb2O5. This suggests that Nb was replaced by Fe and, therefore, there are no significant variations in the oxide structure. The crystallite size of Fe-doped Nb2O5 nanostructured particles increased in all cases when the sintering temperature increased from 600 to 700 °C. The band gap energy of Nb2O5:Fe decreased with increased temperature for 2.5 and 5 % concentrations. The S BET value increased with increased iron concentration. The 5 % Nb2O5:Fe sample, calcined at 700 °C, showed an E g of approximately 2.69 eV and structural and superficial characteristics that make it promising for photocatalytic performance tests.

Keywords : Nb₂O₅: Fe, Pechini method; photocatalysis; thermal treatment; structural properties.

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