Details
| Original language | English |
|---|---|
| Pages (from-to) | 7846-7855 |
| Number of pages | 10 |
| Journal | New journal of chemistry |
| Volume | 40 |
| Issue number | 9 |
| Publication status | Published - 2016 |
Abstract
The preparation of titanium dioxide nanoparticles doped with nitrogen for application as a photocatalyst in the decomposition of azo dyes was optimized by factorial planning. Five variables were evaluated and the results showed that the stirring method of the reaction medium, the nitrogen source and the calcination temperature are the determining parameters that affect the photocatalytic activity. With this methodology, it was possible to obtain an optimized photocatalyst (K1) with high surface area and high mineralization efficiency (100%) of the dye Ponceau 4R under solar irradiation. K1, its non-doped version and the worst photocatalyst obtained by the factorial planning (K2) were characterized by several techniques to rationalize the different behaviors. The observed mineralization rate constants under artificial UV-A radiation were in the order of 10 -2, 10 -4 and 10 -3 min -1, respectively, for K1, K2 and the non-doped oxide. As shown by N 2 sorption isotherms, the powders exhibited large variations in porosity as well as in the specific surface area, with values ranging from 63.03 m 2 g -1 for K1 to 12.82 m 2 g -1 for K2. Infrared spectra showed that the calcination of the doped oxides between 300 and 500 °C leads to considerable loss of the nitrogen content, which is corroborated by XPS measurements that also indicate the presence of oxygen vacancies on their surfaces. Nanosecond transient absorption measurements show that the electron-hole half-lifetime in K1 is 870 ns, ca. two times longer than that observed for the other photocatalysts. Additionally, dye degradation studies under solar radiation reveal that K1 is ca. 28% faster than the non-doped TiO 2 under similar conditions. This higher photoactivity for K1 is attributed to its extended visible light absorption and the optimized morphological and electronic properties.
ASJC Scopus subject areas
- Chemical Engineering(all)
- Catalysis
- Chemistry(all)
- General Chemistry
- Materials Science(all)
- Materials Chemistry
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In: New journal of chemistry, Vol. 40, No. 9, 2016, p. 7846-7855.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Characterization of a highly efficient N-doped TiO2 photocatalyst prepared
T2 - Via factorial design
AU - Borges, K.A.
AU - Santos, L.M.
AU - Paniago, R.M.
AU - Barbosa Neto, N.M.
AU - Schneider, J.
AU - Bahnemann, D.W.
AU - Patrocinio, A.O.T.
AU - Machado, A.E.H.
N1 - Publisher Copyright: © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2016. Copyright: Copyright 2020 Elsevier B.V., All rights reserved.
PY - 2016
Y1 - 2016
N2 - The preparation of titanium dioxide nanoparticles doped with nitrogen for application as a photocatalyst in the decomposition of azo dyes was optimized by factorial planning. Five variables were evaluated and the results showed that the stirring method of the reaction medium, the nitrogen source and the calcination temperature are the determining parameters that affect the photocatalytic activity. With this methodology, it was possible to obtain an optimized photocatalyst (K1) with high surface area and high mineralization efficiency (100%) of the dye Ponceau 4R under solar irradiation. K1, its non-doped version and the worst photocatalyst obtained by the factorial planning (K2) were characterized by several techniques to rationalize the different behaviors. The observed mineralization rate constants under artificial UV-A radiation were in the order of 10 -2, 10 -4 and 10 -3 min -1, respectively, for K1, K2 and the non-doped oxide. As shown by N 2 sorption isotherms, the powders exhibited large variations in porosity as well as in the specific surface area, with values ranging from 63.03 m 2 g -1 for K1 to 12.82 m 2 g -1 for K2. Infrared spectra showed that the calcination of the doped oxides between 300 and 500 °C leads to considerable loss of the nitrogen content, which is corroborated by XPS measurements that also indicate the presence of oxygen vacancies on their surfaces. Nanosecond transient absorption measurements show that the electron-hole half-lifetime in K1 is 870 ns, ca. two times longer than that observed for the other photocatalysts. Additionally, dye degradation studies under solar radiation reveal that K1 is ca. 28% faster than the non-doped TiO 2 under similar conditions. This higher photoactivity for K1 is attributed to its extended visible light absorption and the optimized morphological and electronic properties.
AB - The preparation of titanium dioxide nanoparticles doped with nitrogen for application as a photocatalyst in the decomposition of azo dyes was optimized by factorial planning. Five variables were evaluated and the results showed that the stirring method of the reaction medium, the nitrogen source and the calcination temperature are the determining parameters that affect the photocatalytic activity. With this methodology, it was possible to obtain an optimized photocatalyst (K1) with high surface area and high mineralization efficiency (100%) of the dye Ponceau 4R under solar irradiation. K1, its non-doped version and the worst photocatalyst obtained by the factorial planning (K2) were characterized by several techniques to rationalize the different behaviors. The observed mineralization rate constants under artificial UV-A radiation were in the order of 10 -2, 10 -4 and 10 -3 min -1, respectively, for K1, K2 and the non-doped oxide. As shown by N 2 sorption isotherms, the powders exhibited large variations in porosity as well as in the specific surface area, with values ranging from 63.03 m 2 g -1 for K1 to 12.82 m 2 g -1 for K2. Infrared spectra showed that the calcination of the doped oxides between 300 and 500 °C leads to considerable loss of the nitrogen content, which is corroborated by XPS measurements that also indicate the presence of oxygen vacancies on their surfaces. Nanosecond transient absorption measurements show that the electron-hole half-lifetime in K1 is 870 ns, ca. two times longer than that observed for the other photocatalysts. Additionally, dye degradation studies under solar radiation reveal that K1 is ca. 28% faster than the non-doped TiO 2 under similar conditions. This higher photoactivity for K1 is attributed to its extended visible light absorption and the optimized morphological and electronic properties.
UR - http://www.scopus.com/inward/record.url?scp=84985023146&partnerID=8YFLogxK
U2 - 10.1039/c6nj00704j
DO - 10.1039/c6nj00704j
M3 - Article
VL - 40
SP - 7846
EP - 7855
JO - New journal of chemistry
JF - New journal of chemistry
SN - 0398-9836
IS - 9
ER -