Evaluación de la actividad fotocatalítica de nanoestructuras de T-Nb2O5 obtenidas por el método sol-gel
Evaluación de la actividad fotocatalítica de nanoestructuras de T-Nb2O5 obtenidas por el método sol-gel
Barra lateral del artículo
PDF
FLIP
Contenido principal del artículo
Antecedentes: La fase T del pentóxido de niobio (Nb2O5) absorbe energía en la región del ultravioleta lo que lo hace un material promisorio en aplicaciones fotocatalíticas. Objetivo: En este trabajo se sintetizó, caracterizó y evaluó la actividad fotocatalítica, en la degradación de Rodamina B, del T-Nb2O5. Metodología: Las muestras fueron preparadas por el método sol-gel siguiendo dos procedimientos diferentes (NH4OH y H2O); los materiales fueron sinterizados a temperaturas de 650 °C y 750 °C y caracterizados por DRX, MEB y espectroscopias IR e UV-vis. Resultados: El NH4OH modifica el tamaño cristalino, la energía de banda gap y la porosidad del T-Nb2O5, además inhibe el crecimiento de nanopartículas de Nb2O5 en el proceso sol-gel, por lo tanto se ve modificada la cinética para la degradación de Rodamina B. La actividad fotocatalítica de las nanoestructuras es dominantemente determinada por el equilibrio de absorción y la cinética de la reacción. Conclusión: Los resultados de caracterización estructural, morfológica, vibracional y óptica permiten inferir que se obtuvo la cristalización del T-Nb2O5 y que a 750 °C el material exhibió una mayor eficiencia en la actividad fotocatalítica.
Palabras clave: caracterización, catalizador, fotocatálisis, pentóxido de niobio, sol-gel.
Abstract
Background: T phase of Niobium pentoxide (Nb2O5) absorbs energy in the ultraviolet region which makes it a promissory material in photocatalytic applications. Objective: In this work the T-Nb2O5 was synthesized, characterized and its photocatalytic performance for degradation of Rhodamine B was evaluated. Methods: The samples were made by the sol-gel method following two different procedures (NH4OH and H2O); the materials were sintered at 650 °C and 750 °C temperatures and later characterized by XRD, SEM, IR and UV-vis spectroscopy. Results: NH4OH modifies the T-Nb2O5 crystalline size, band-gap energy, and porosity, besides inhibiting the growth of Nb2O5 nanoparticles in sol-gel process, and therefore the kinetics for Rhodamine B degradation are modified. The photocatalytic activity of the nanostructures is dominantly determined by adsorption equilibrium and reaction kinetics. Conclusions: The results of structural, morphological, vibrational and optic characterization allow to conclude that the crystallization of T-Nb 2 O 5 was achieved, and that the material treated at 750°C showed an increased efficiency in the photocatalytic activity.
Key words: characterization, catalyst, photocatalysis, niobium pentoxide, sol-gel.
Resumo
Antecedentes: A fase T do pentóxido de nióbio (Nb₂O₅) absorve energia na região do ultravioleta tornando-se um material promissor para aplicações catalíticas. Objectivo: Neste estudo foi sintetizado, caracterizar e avaliar a actividade fotocatalítica na degradação de Rodamina B, o T-Nb2 O5 . Metodologia: As amostras foram preparadas pelo método de sol-gel, seguindo dois procedimentos diferentes: (NH4 OH e H2 O). Finalmente as amostras foram sinterizados a temperaturas de 650 °C e 750 °C para logo ser caracterizadas por: DRX, SEM e espectroscopia de IV e UV-VIS. Resultados: O uso do NH4 OH modifica o tamanho dos cristalitos, a energia da banda e a porosidade do T-Nb2 O5 , também inibe o crescimento de nanopartículas Nb2 O5 no processo sol-gel, por conseguinte, a cinética de degradação de Rodamina B. A é modificado. Conclusão: Os resultados da caracterização estrutural, morfológica, vibracional e óptico permitem inferir que foi obtido a cristalização da T-Nb2 O5. Assim, as amostra em 750 °C apresentam uma maior eficiência na actividade fotocatalítica.
Palavras-chave: caracterização, catalisador, fotocatálise, pentoxido de niobio, sol-gel.
Descargas
Detalles del artículo
A. G.S. Prado, L. B. Bolzon, C. P. Pedroso, et al. “Nb2O5 as efficient and recyclable photocatalyst for indigo carmine degradation” Appl. Catal. B Environ, vol. 82, no. 3–4, pp. 29–224, 2008.
O. F. Lopes, E. C. Paris, and C. Ribeiro. “Synthesis of Nb2O5 nanoparticles through the oxidant peroxide method applied to organic pollutant photodegradation: A mechanistic study” Appl. Catal. B Environ, vol. 144, pp. 800–808, 2014.
N. Uekawaa, T. Kudoc, F. Morid, et al. “Low-temperature synthesis of niobium oxide nanoparticles from peroxo niobic acid sol” J. Colloid Interface Sci., vol. 264, no. 2, pp. 378–384, 2003.
N. Pinna, M. Antonietti, and M. Niederberger . “A novel nonaqueous route to V2O3 and Nb2O5 nanocrystals” Colloids Surf. -Physicochem. Eng. Asp, vol. 250, no. 1–3, pp. 211–213, 2004.
M. A. Fox and M. T. Dulay. “Heterogeneous photocatalysis” Chem. Rev, vol. 93, no. 1, pp. 341–357, 1993.
M.R.N. Soares, S. Leitea, C. Nicoa, et al. “Effect of processing method on physical properties of Nb2O5 ” Journal of the European Ceramic Society, vol. 31, pp. 501–506, 2011.
F. Hashemzadeh, R. Rahimi, and A. Gaffarinejad. “Photocatalytic degradation of methylene blue and rhodamine B dyes by niobium oxide nanoparticles synthesized via hydrothermal method” Int. J. Appl. Chem. Sci. Res, vol. 1, no. 7, pp. 95–102, 2013.
G.B. Saupe, Y. Zhao, J. Bang, et al. “Evaluation of a new porous titaniumniobium mixed oxide for photocatalytic water decontamination” Microchem. J, vol. 81, no. 1, pp. 156–162, 2005.
A. M. Raba, D. N. Suarez, J. J. Martínez, et al. “Uso del método Pechini en la obtención de nanopartículas semiconductoras a base de niobio” DYNA, vol. 82, no. 189, pp. 52–58, 2015.
H. Komunami, K. Oki, M. Kohno, et al. “Novel solvothermal synthesis of niobium (V) oxide powders and their photocatalytic activity in aqueous suspensions” J. Mater. Chem, vol. 11, no. 2, pp. 604–609, 2001.
T. Tsuzuki and P. G. McCormick, “Mechanochemical Synthesis of Niobium Pentoxide Nanoparticles” Mater. Trans, vol. 42, no. 8, pp. 1623–1628, 2001.
P. Griesmar, G. Papin, C. Sanchez and J. Livage. “Sol-gel route to niobium pentoxide” Chem. Mater., vol. 3, no. 2, pp. 335–339, 1991.
M. P. F. Graça. “Nb2O5 nanosize powders prepared by sol–gel Structure, morphology and dielectric properties” J. Alloys Compd, vol. 553, pp. 177–182, 2013.
M. Ristić, S. Popović and S. Musić, “Sol–gel synthesis and characterization of Nb2O5 powders” Mater. Lett, vol. 58, no. 21, pp. 2658–2663, 2004.
S. Furukawa, Y. Ohno, T. Shishido, et al. “Reaction Mechanism of Selective Photooxidation of Amines over Niobium Oxide: Visible-Light Induced Electron Transfer between Adsorbed Amine and Nb2O5 ” J. Phys. Chem. C, vol. 117, no. 1, pp. 442–450, 2013.
T. Shishido, T. Miyatake, K. Teramura, et al. “Mechanism of Photooxidation of Alcohol over Nb2O5”. J. Phys. Chem. C, vol. 113, no. 43, pp. 18713–18718,2009.
X. Chena, T. Yua, X. Fanb, et al. “Enhanced activity of mesoporous Nb2O5 for photocatalytic hydrogen production” Appl. Surf. Sci., vol. 253, no. 20, pp. 8500–8506, 2007.
M. Catauroa, C. Pagliucaa, L. Lisib and G. Ruoppoloc. “Synthesis of alkoxidederived V-Nb catalysts prepared by sol–gel route” Thermochim. Acta, vol. 381, no. 1, pp. 65–72, 2002.
T. Sreethawonga, S. Ngamsinlapasathianb, S. H. Lima and S. Yoshikawab. “Investigation of thermal treatment effect on physicochemical and photocatalytic H2 production properties of mesoporous-assembled Nb2O5 nanoparticles synthesized via a surfactant-modified sol–gel method” Chem. Eng. J., vol. 215–216, pp. 322–330, 2013.
A. M. Raba, J. Barba Ortega, and M. R. Joya, “The effect of the preparation method of Nb2O5 oxide influences the performance of the photocatalytic activity” Appl. Phys. A, vol. 119, no. 3, pp. 923–928, 2015.
M. Galceran, M. C. Pujol, M. Aguiló and F. Díaz. “Sol-gel modified Pechini method for obtaining nanocrystalline PP: 80-91 Angela Mercedes Raba-Páez, Ciro Falcony-Guajardo, Miryam Rincón-Joya KRE (WO4)2(RE= Gd and Yb)” J. Sol-Gel Sci. Technol, vol. 42, no. 1, pp. 79–88, 2007.
B. Neppolian, S. Sakthivel, B. Arabindoo and M. Palanichamy. “Kinetics of Photocatalytic Degradation of Reactive Yellow 17 Dye in Aqueous Solution Using Uv Irradiation” J. Environ. Sci. Health Part A, vol. 36, no. 2, pp. 203–213, 2001.
