Effect of the concentration of iron in the properties of Nb2O5 with posible photocatalitic application
Abstract
At present, it is searching to develop low gap band energy compounds to be applied in photocatalysis. Niobium pentoxide was doped with iron in order to establish the relationship between its structural, morphological and surface properties, and possible photocatalytic applications. Nb2O5 doped with Fe (at 2.5%, 5% and 10%, percentage by weight) powders were prepared through the Pechini method, this seeking to establish the appropriate synthesis conditions for the formation of Nb2O5: Fe particles. The powders were sintered at 600°C and 700°C for 2 hours in air and afterwards were examined by TGA, XRD, SEM, UV-vis diffuse reflectance spectroscopy and by the BET method. The thermal analysis allowed establishing the behavior of the percentage of weight loss as a function of temperature in the precalcined samples. Results obtained for non-doped oxide were compared with those of Nb2O5 doped with Fe to analyze its crystalline properties. The Nb2O5 doped with Fe at 2.5% and 5% diffractograms, subjected to 700°C, were similar to that of the non-doped oxide indicating that Nb was replaced by Fe and, therefore, there are not significant variations in the oxide structure. The crystallite size of the Nb2O5 doped with Fe nanostructured particles it was increased in all cases, when the sintering temperature was increased from 600°C to 700°C. The gap band energy of Nb2O5:Fe decreased with the temperature increase for the concentrations of 2.5% and 5%. The SBET value increased with the iron concentration increase. The sample Nb2O5:Fe5%, calcined at 700°C, showed an Eg of approximately 2.69 eV and structural and superficial characteristics that make it promising for tests of photocatalytic performance.Downloads
References
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