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Influence of crystal structure of nanosized ZrO2 on photocatalytic degradation of methyl orange.

Basahel SN, Ali TT, Mokhtar M, Narasimharao K - Nanoscale Res Lett (2015)

Bottom Line: The structural and textural properties of the samples were analyzed by X-ray diffraction, Raman spectroscopy, TEM, UV-vis, X-ray photoelectron spectroscopy (XPS), and N2 adsorption measurements.The photocatalytic activity of the pure monoclinic ZrO2 sample is higher than that of the tetragonal and cubic ZrO2 samples under optimum identical conditions.The higher activity of the monoclinic ZrO2 sample for the photocatalytic degradation of methyl orange can be attributed to the combining effects of factors including the presence of small amount of oxygen-deficient zirconium oxide phase, high crystallinity, large pores, and high density of surface hydroxyl groups.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, Faculty of Science, King Abdulaziz University, P. O. Box, 80203, Jeddah, 21589 Kingdom of Saudi Arabia.

ABSTRACT
Nanosized ZrO2 powders with near pure monoclinic, tetragonal, and cubic structures synthesized by various methods were used as catalysts for photocatalytic degradation of methyl orange. The structural and textural properties of the samples were analyzed by X-ray diffraction, Raman spectroscopy, TEM, UV-vis, X-ray photoelectron spectroscopy (XPS), and N2 adsorption measurements. The performance of synthesized ZrO2 nanoparticles in the photocatalytic degradation of methyl orange under UV light irradiation was evaluated. The photocatalytic activity of the pure monoclinic ZrO2 sample is higher than that of the tetragonal and cubic ZrO2 samples under optimum identical conditions. The characterization results revealed that monoclinic ZrO2 nanoparticles possessed high crystallinity and mesopores with diameter of 100 Å. The higher activity of the monoclinic ZrO2 sample for the photocatalytic degradation of methyl orange can be attributed to the combining effects of factors including the presence of small amount of oxygen-deficient zirconium oxide phase, high crystallinity, large pores, and high density of surface hydroxyl groups.

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Nitrogen adsorption-desorption isotherms and pore size distribution (inset) of the samples.
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Fig4: Nitrogen adsorption-desorption isotherms and pore size distribution (inset) of the samples.

Mentions: A typical nitrogen adsorption-desorption isotherms of the samples are shown in Figure 4. The adsorption-desorption patterns of the three ZrO2 samples belong to the typical IUPAC IV-type with the H2-type hysteresis loop, which is a characteristic of particles with uniform size and mesoporous structure [37]. From the figure, it is clear that all the three samples showed type IV isotherms with hysteresis loop at P/Po = 0.45 to 0.95. However, each sample exhibited a different type of hysteresis loop suggesting that pore size and shape were not same in these samples. The H2-type adsorption hysteresis can be explained as a consequence of the interconnectivity of pores. It was reported that in such systems, the distribution of pore sizes and pore shapes are not well defined or irregular. A sharp step on desorption isotherm is usually understood as a sign of interconnection of the pores. The shape of hysteresis loop of the m-ZrO2 sample suggesting that this sample possessed pores known as ‘ink-bottle’ type [38].Figure 4


Influence of crystal structure of nanosized ZrO2 on photocatalytic degradation of methyl orange.

Basahel SN, Ali TT, Mokhtar M, Narasimharao K - Nanoscale Res Lett (2015)

Nitrogen adsorption-desorption isotherms and pore size distribution (inset) of the samples.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4385125&req=5

Fig4: Nitrogen adsorption-desorption isotherms and pore size distribution (inset) of the samples.
Mentions: A typical nitrogen adsorption-desorption isotherms of the samples are shown in Figure 4. The adsorption-desorption patterns of the three ZrO2 samples belong to the typical IUPAC IV-type with the H2-type hysteresis loop, which is a characteristic of particles with uniform size and mesoporous structure [37]. From the figure, it is clear that all the three samples showed type IV isotherms with hysteresis loop at P/Po = 0.45 to 0.95. However, each sample exhibited a different type of hysteresis loop suggesting that pore size and shape were not same in these samples. The H2-type adsorption hysteresis can be explained as a consequence of the interconnectivity of pores. It was reported that in such systems, the distribution of pore sizes and pore shapes are not well defined or irregular. A sharp step on desorption isotherm is usually understood as a sign of interconnection of the pores. The shape of hysteresis loop of the m-ZrO2 sample suggesting that this sample possessed pores known as ‘ink-bottle’ type [38].Figure 4

Bottom Line: The structural and textural properties of the samples were analyzed by X-ray diffraction, Raman spectroscopy, TEM, UV-vis, X-ray photoelectron spectroscopy (XPS), and N2 adsorption measurements.The photocatalytic activity of the pure monoclinic ZrO2 sample is higher than that of the tetragonal and cubic ZrO2 samples under optimum identical conditions.The higher activity of the monoclinic ZrO2 sample for the photocatalytic degradation of methyl orange can be attributed to the combining effects of factors including the presence of small amount of oxygen-deficient zirconium oxide phase, high crystallinity, large pores, and high density of surface hydroxyl groups.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, Faculty of Science, King Abdulaziz University, P. O. Box, 80203, Jeddah, 21589 Kingdom of Saudi Arabia.

ABSTRACT
Nanosized ZrO2 powders with near pure monoclinic, tetragonal, and cubic structures synthesized by various methods were used as catalysts for photocatalytic degradation of methyl orange. The structural and textural properties of the samples were analyzed by X-ray diffraction, Raman spectroscopy, TEM, UV-vis, X-ray photoelectron spectroscopy (XPS), and N2 adsorption measurements. The performance of synthesized ZrO2 nanoparticles in the photocatalytic degradation of methyl orange under UV light irradiation was evaluated. The photocatalytic activity of the pure monoclinic ZrO2 sample is higher than that of the tetragonal and cubic ZrO2 samples under optimum identical conditions. The characterization results revealed that monoclinic ZrO2 nanoparticles possessed high crystallinity and mesopores with diameter of 100 Å. The higher activity of the monoclinic ZrO2 sample for the photocatalytic degradation of methyl orange can be attributed to the combining effects of factors including the presence of small amount of oxygen-deficient zirconium oxide phase, high crystallinity, large pores, and high density of surface hydroxyl groups.

No MeSH data available.


Related in: MedlinePlus