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Dielectric and photo-catalytic studies of rapidly synthesized m-WO3 nano-particles
Materials Today: Proceedings xxx (xxxx) xxx
Contents lists available at ScienceDirect
Materials Today: Proceedings journal homepage: www.elsevier.com/locate/matpr
Dielectric and photo-catalytic studies of rapidly synthesized m-WO3 nano-particles Vijay Luxmi ⇑, Ashavani Kumar Department of Physics, NIT Kurukshetra, Kurkshetra, Haryana, India
a r t i c l e
i n f o
Article history: Received 24 January 2020 Accepted 28 January 2020 Available online xxxx Keywords: Photo-catalyst Dielectric WO3 Methylene blue Dye Calcination
a b s t r a c t In this paper, monoclinic-WO3 nano-particles were successfully synthesized via co-precipitation method pursued by calcination at two thermal treatments 500 °C and 800 °C. Nyquist plots (Cole-Cole plot) and the tangent loss factor (tan d) were discussed with frequency function in the range 1 Hz to 5 MHz for dielectric studies. Reduction in resistance and tangent loss factor has been observed in WO3 (800 °C) which is due to grain boundary contribution. Photocatalysis is attracting enormous attention towards addressing existing energy and environmental affairs via transforming visible light into chemical energy. For photocatalytic studies, MB dye was used as a toxic organic pollutant. Results shows that WO3 photocatalyst calcined at 800 °C exhibits enhanced photocatalytic performance under visible light irradiation. Ó 2020 Elsevier Ltd. All rights reserved. Selection and Peer-review under responsibility of the scientific committee of the International Conference on Advanced Materials and Nanotechnology.
1. Introduction Tungsten (VI) trioxide (WO3) is a semiconductor having approximate energy band gap (Eg) in the range of 2.5–2.8 eV. It has many applications like it is used in paints and ceramics because of its rich yellow color, in making smart and electrochromic windows, tungstates in making x-ray screen phosphors, fire proof jackets, gas sensing, energy storage devices and in the photocatalytic degradation of various dyes under the influence of visible light [1–3]. Actually, various textile and paper industries discharge huge amounts of colored dye waste such as methyl red, congo red, methyl orange, thymol blue, methylene blue, rhodamine B/6G etc. in ponds, rivers which are toxic and non-biodegradable [4]. Most of the dyestuffs are difficult to decompose as aromatic dyes have relatively stable chemical structures which causes contamination in drinking water and in some areas irrigation system also affected [5]. Over the past many decades, for the de-coloration of dye effluences, various chemical, physical and biological techniques have been developed. One of the efficient and economical method for the de-coloration of dye effluents is semiconductor mediated photocatalysis under visible-light, UV–Visible and NIR irradiation [6]. In the present work, a rapid synthesis of m-WO3 nano-particles at two different calcination temperatures (500 °C and 800 °C) via ⇑ Corresponding author. E-mail address: [email protected] (V. Luxmi).
precipitation method in ethanol solution is reported. These nanoparticles were prepared by similar process as synthesized earlier in the presence of complexing agent [7] and the prepared WO3 nano-particles were characterized by various techniques. Nyquist plot (Cole-Cole plot) and dielectric loss (tan d) were considered as a function of frequency and observed within the frequency range 1 Hz to 5 MHz. The photocatalytic performance of the WO3 (500 °C and 800 °C) were studied by observing de-coloration in methylene blue (MB) absorbance peak under the illumination of visible light. 2. Experimental detail 2.1. Chemicals used For the synthesis of tungsten (VI) oxide (WO3) nano-particles, ammonium para tungstate hydrate ((NH4)10(W12O41)5H2O), ethanol (C2H6O), nitric acid (HNO3) and hydrogen peroxide (H2O2) (Loba India) were used as precursor materials. For the photocatalytic activity, methylene blue (C16H18N3SCl) dye (Loba India) was used. 2.2. Synthesis procedure WO3 nano-particles (Tungsten (VI) oxide) were precipitately prepared with ammonium para tungstate hydrate dissolved in
https://doi.org/10.1016/j.matpr.2020.01.544 2214-7853/Ó 2020 Elsevier Ltd. All rights reserved. Selection and Peer-review under responsibility of the scientific committee of the International Conference on Advanced Materials and Nanotechnology.
Please cite this article as: V. Luxmi and A. Kumar, Dielectric and photo-catalytic studies of rapidly synthesized m-WO3 nano-particles, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2020.01.544
2
V. Luxmi, A. Kumar / Materials Today: Proceedings xxx (xxxx) xxx
50 ml of ethanol (10.23 g) by stirring continuously at 70 °C. After 1 h, 5 ml of nitric acid was added drop wise to the solution sample with constantly stirring for about 30 min. to adjust the pH value approx. 1. The solution collected was heated up until the ethanol had completely evaporated. Finally, obtained precipitates were washed with H2O2 several times and dried for 12 h in an oven at 80 °C. Hereafter, precipitates were calcined at two temperatures 500 °C and 800 °C for 2 h and then the calcined powder was grounded well for further characterization. 2.3. Photo-catalytic measurements The solutions for photo-degradation were prepared by adding WO3 samples 0.1 g to 100 ml dye solution of methylene blue (1 mg/100 ml).
3. Characterizations 3.1. Dielectric studies Fig. 1 shows the complex impedance behavior of WO3 samples. To know the conduction mechanism of prepared samples, impedance of WO3 samples were observed within frequency region 1 Hz to 5 MHz. This impedance spectroscopy is very constructive and prominent technique for the synthesized samples that facilitates to arbitrate the correlation of the electrical transport properties with its nanostructures. The complex impedance spectra, which is well-known as Cole-Cole (Nyquist plot) is determined by the appearance of crescent shaped arcs. As the sintering temperature of the samples increases, diameter of arcs decreases. In the Nyquist plot (Re (Z) vs –Img (Z) or Z0 vs. Z00 ), arcs at lower frequency region approaches to the grain boundaries of crystal, whereas the arcs in the high frequency region reveal the grains. The net impedance is estimated by Z = Z0 + iZ00 , where Z0 or Re (Z) represents the real part of net impedance and Z00 or Img (Z) represents the imaginary part of net impedance related to the capacitance. From Fig. 1, it is observed that the only one semicircular arc obtained for both samples sintered at 500 °C and 800 °C synthesized via precipitation method, suggesting a predominant involvement from the grain boundaries of the crystal. Hence, the conductivity of WO3 samples is generally due to the contribution of grain boundary. With rise in sintering temperature, the decrease in diameter of the arc reveals the decrement in grain boundaries and resistance of electrode interface. This reduction reveals
Fig. 1. Room temperature complex impedance spectroscopic behaviour of WO3 nano-particles sintered at 500 °C and 800 °C.
enhancement in conductivity and reduction in relaxation time with rise in the sintering temperature of WO3 samples. Fig. 2 shows the change in tangent loss factor (tan d) with frequency (log x) of WO3 nano-particles at room temperature. Tangent loss factor (tan d) was obtained by the formula as mentioned in equation 1:
e00 ¼ e0 tand
ð1Þ
1 , C ¼ e0dA, e0 represents free space permittivity, A ðxRp C o Þ o represents electrode area and d represents the thickness of the sample. From the Fig. 2, it is clear that tangent loss versus frequency curves for both the samples (WO3 sintered at 500 °C and 800 °C) shows anomalous dielectric performance by showing higher values of tan d at lower frequency. The maximum loss was scrutinized due to the hopping frequency of electrons involved in it and becomes relatively identical to the frequency of the applied field. A continuous variation in maxima (xmax) with variation in sintering temperature of the samples indicates the jumping or hopping probability per unit time is varying continuously. With increase in frequency, the tangent loss factor decreases, possibly due to the space charge deviation that take place at grain boundaries with the effect of growth of charge carriers under the presence of an applied field.
where e00 ¼
3.2. Photocatalytic studies In order to study the photo-catalytic responses of WO3 photocatalyst, concentration of MB in the solution was measured by the UV–Vis spectrometer (Camspec) optical absorption peak at 664 nm, as noted with a certain absorption concentration standard curve. The de-coloration efficiency of WO3 photo-catalysts was evaluated using formula [8–9] cited in Eq. (2).
Efficiency ð%Þ ¼ ððC o C t ÞÞ=C o 100
ð2Þ
Where Co and Ct are respectively the original absorbance and absorption after ‘t’ time irradiation. Fig. 3 shows degradation profiles of MB dye (a) without catalyst (b) in the presence of WO3 (500 °C) (c) in the presence of WO3 (800 °C) (d) concentration verses time plot. It can be observed that WO3 calcined at 500 °C shows lesser degradation which is 86.8% in 220 min. in comparison with WO3 calcined at 800 °C which is 96.7% in 160 min. The better photocatalytic activity of WO3 was observed with WO3 calcined at 800 °C. This activity attributed
Fig. 2. Dielectric loss (tan d) verses frequency (log x) curves of WO3 calcined at 500 °C and 800 °C.
Please cite this article as: V. Luxmi and A. Kumar, Dielectric and photo-catalytic studies of rapidly synthesized m-WO3 nano-particles, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2020.01.544
V. Luxmi, A. Kumar / Materials Today: Proceedings xxx (xxxx) xxx
3
Fig. 3. Time reliant UV-visible absorption spectra for de-coloration of MB dye (a) without photo-catalyst (b) with WO3 (500 °C) (c) with WO3 (800 °C) (d) concentration verses time plot.
due to the crystallinity of WO3 which results in decreased number of defects and avoids electron-hole pairs recombination. Furthermore, other parameters like energy band gap (Eg) and specific surface area do not contribute much in photocatalytic activity due to small surface area and energy band gap values (Eg) of WO3 (500 °C) and (800 °C) [7].
Acknowledgements The authors are glad to honour the Director, NIT Kurukshetra for providing the Physics Department with scholarship and characterization equipments. References
4. Conclusions In the present work, WO3 nano-structures calcined at two different temperatures (500 °C and 800 °C) were successfully synthesized via co-precipitation method. Complex impedance spectroscopic activities of WO3 nano-particles is clearly visible in Cole-Cole plot (Nyquist plot) which reveals that with rise in calcining temperature, enhancement in conductivity with reduction in relaxation time takes place. Reduction in resistance and dielectric loss factor (tan d) is observed with calcining via plotting dielectric loss (tan d) versus frequency (log x). Photocatalytic results show that synthesized WO3 (800 °C) nano-particles possesses enhanced photocatalytic activity in degrading MB dye under visible light i.e. 96.7% in 160 min with rate constant k 0.01878. It is attributed due to efficient separation of electron-hole during photocatalytic activity. Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
[1] G.R. Bamwenda, H. Arakawa, The visible light induced photocatalytic activity of tungsten trioxide powders, J. Appl. Catal. A 210 (2001) 181–191. [2] W.J. Lee, Y.K. Fang, J.J. Ho, W.T. Hsieh, S.F. Ting, Effects of surface porosity on tungsten trioxide (WO3) films’ electrochromic performance, J. Electr. Mater. 29 (2000) 183–187. [3] H. Turkez, B. Cakmak, K. Celik, Evaluation of the potential in vivo genotoxicity of tungsten (VI) oxide nano powder for human health, J. Eng. Mater. 543 (2013) 89–92. [4] P. Broker, A.V. Salker, Photocatalytic degradation of textile azo dye over Ce1xSnxO2 series, J. Mater. Sci. Eng. B 133 (2006) 55. [5] R. Jiang, H. Zhu, X. Li, L. Xiao, Visible light photocatalytic decolourization of CI Acid Red 66 by chitosan capped CdS composite nanoparticles, J. Chem. Eng. 152 (2009) 537–542. [6] H. Zhu, R. Jiang, L. Xiao, Y. Chang, Y. Guan, X. Li, G. Zeng, Photocatalytic decolorization and degradation of Congo Red on innovative crosslinked chitosan/nano-CdS composite catalyst under visible light irradiation, J. Hazard. Mater. 169 (2009) 933–940. [7] D.S. Martínez, A. Martínez-De La Cruz, E.L. Cuéllar, Photocatalytic properties of WO3 nanoparticles obtained by precipitation in presence of urea as complexing agent, J. Appl. Catal. A 398 (2011) 179–186. [8] V. Luxmi, A. Kumar, Enhanced photocatalytic performance of m-WO3 and m-Fedoped WO3 cuboids synthesized via sol-gel approach using egg albumen as a solvent, J. Mater. Sci. Semicond. Process. 104 (2019) 104690. [9] A. Kumar, V. Luxmi, Novel green photo-catalyst ‘turmeric roots’ for pesticides degradation: preparation and characterizations, J. Mater. Lett. (2019) 127030.
Please cite this article as: V. Luxmi and A. Kumar, Dielectric and photo-catalytic studies of rapidly synthesized m-WO3 nano-particles, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2020.01.544
Contents lists available at ScienceDirect
Materials Today: Proceedings journal homepage: www.elsevier.com/locate/matpr
Dielectric and photo-catalytic studies of rapidly synthesized m-WO3 nano-particles Vijay Luxmi ⇑, Ashavani Kumar Department of Physics, NIT Kurukshetra, Kurkshetra, Haryana, India
a r t i c l e
i n f o
Article history: Received 24 January 2020 Accepted 28 January 2020 Available online xxxx Keywords: Photo-catalyst Dielectric WO3 Methylene blue Dye Calcination
a b s t r a c t In this paper, monoclinic-WO3 nano-particles were successfully synthesized via co-precipitation method pursued by calcination at two thermal treatments 500 °C and 800 °C. Nyquist plots (Cole-Cole plot) and the tangent loss factor (tan d) were discussed with frequency function in the range 1 Hz to 5 MHz for dielectric studies. Reduction in resistance and tangent loss factor has been observed in WO3 (800 °C) which is due to grain boundary contribution. Photocatalysis is attracting enormous attention towards addressing existing energy and environmental affairs via transforming visible light into chemical energy. For photocatalytic studies, MB dye was used as a toxic organic pollutant. Results shows that WO3 photocatalyst calcined at 800 °C exhibits enhanced photocatalytic performance under visible light irradiation. Ó 2020 Elsevier Ltd. All rights reserved. Selection and Peer-review under responsibility of the scientific committee of the International Conference on Advanced Materials and Nanotechnology.
1. Introduction Tungsten (VI) trioxide (WO3) is a semiconductor having approximate energy band gap (Eg) in the range of 2.5–2.8 eV. It has many applications like it is used in paints and ceramics because of its rich yellow color, in making smart and electrochromic windows, tungstates in making x-ray screen phosphors, fire proof jackets, gas sensing, energy storage devices and in the photocatalytic degradation of various dyes under the influence of visible light [1–3]. Actually, various textile and paper industries discharge huge amounts of colored dye waste such as methyl red, congo red, methyl orange, thymol blue, methylene blue, rhodamine B/6G etc. in ponds, rivers which are toxic and non-biodegradable [4]. Most of the dyestuffs are difficult to decompose as aromatic dyes have relatively stable chemical structures which causes contamination in drinking water and in some areas irrigation system also affected [5]. Over the past many decades, for the de-coloration of dye effluences, various chemical, physical and biological techniques have been developed. One of the efficient and economical method for the de-coloration of dye effluents is semiconductor mediated photocatalysis under visible-light, UV–Visible and NIR irradiation [6]. In the present work, a rapid synthesis of m-WO3 nano-particles at two different calcination temperatures (500 °C and 800 °C) via ⇑ Corresponding author. E-mail address: [email protected] (V. Luxmi).
precipitation method in ethanol solution is reported. These nanoparticles were prepared by similar process as synthesized earlier in the presence of complexing agent [7] and the prepared WO3 nano-particles were characterized by various techniques. Nyquist plot (Cole-Cole plot) and dielectric loss (tan d) were considered as a function of frequency and observed within the frequency range 1 Hz to 5 MHz. The photocatalytic performance of the WO3 (500 °C and 800 °C) were studied by observing de-coloration in methylene blue (MB) absorbance peak under the illumination of visible light. 2. Experimental detail 2.1. Chemicals used For the synthesis of tungsten (VI) oxide (WO3) nano-particles, ammonium para tungstate hydrate ((NH4)10(W12O41)5H2O), ethanol (C2H6O), nitric acid (HNO3) and hydrogen peroxide (H2O2) (Loba India) were used as precursor materials. For the photocatalytic activity, methylene blue (C16H18N3SCl) dye (Loba India) was used. 2.2. Synthesis procedure WO3 nano-particles (Tungsten (VI) oxide) were precipitately prepared with ammonium para tungstate hydrate dissolved in
https://doi.org/10.1016/j.matpr.2020.01.544 2214-7853/Ó 2020 Elsevier Ltd. All rights reserved. Selection and Peer-review under responsibility of the scientific committee of the International Conference on Advanced Materials and Nanotechnology.
Please cite this article as: V. Luxmi and A. Kumar, Dielectric and photo-catalytic studies of rapidly synthesized m-WO3 nano-particles, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2020.01.544
2
V. Luxmi, A. Kumar / Materials Today: Proceedings xxx (xxxx) xxx
50 ml of ethanol (10.23 g) by stirring continuously at 70 °C. After 1 h, 5 ml of nitric acid was added drop wise to the solution sample with constantly stirring for about 30 min. to adjust the pH value approx. 1. The solution collected was heated up until the ethanol had completely evaporated. Finally, obtained precipitates were washed with H2O2 several times and dried for 12 h in an oven at 80 °C. Hereafter, precipitates were calcined at two temperatures 500 °C and 800 °C for 2 h and then the calcined powder was grounded well for further characterization. 2.3. Photo-catalytic measurements The solutions for photo-degradation were prepared by adding WO3 samples 0.1 g to 100 ml dye solution of methylene blue (1 mg/100 ml).
3. Characterizations 3.1. Dielectric studies Fig. 1 shows the complex impedance behavior of WO3 samples. To know the conduction mechanism of prepared samples, impedance of WO3 samples were observed within frequency region 1 Hz to 5 MHz. This impedance spectroscopy is very constructive and prominent technique for the synthesized samples that facilitates to arbitrate the correlation of the electrical transport properties with its nanostructures. The complex impedance spectra, which is well-known as Cole-Cole (Nyquist plot) is determined by the appearance of crescent shaped arcs. As the sintering temperature of the samples increases, diameter of arcs decreases. In the Nyquist plot (Re (Z) vs –Img (Z) or Z0 vs. Z00 ), arcs at lower frequency region approaches to the grain boundaries of crystal, whereas the arcs in the high frequency region reveal the grains. The net impedance is estimated by Z = Z0 + iZ00 , where Z0 or Re (Z) represents the real part of net impedance and Z00 or Img (Z) represents the imaginary part of net impedance related to the capacitance. From Fig. 1, it is observed that the only one semicircular arc obtained for both samples sintered at 500 °C and 800 °C synthesized via precipitation method, suggesting a predominant involvement from the grain boundaries of the crystal. Hence, the conductivity of WO3 samples is generally due to the contribution of grain boundary. With rise in sintering temperature, the decrease in diameter of the arc reveals the decrement in grain boundaries and resistance of electrode interface. This reduction reveals
Fig. 1. Room temperature complex impedance spectroscopic behaviour of WO3 nano-particles sintered at 500 °C and 800 °C.
enhancement in conductivity and reduction in relaxation time with rise in the sintering temperature of WO3 samples. Fig. 2 shows the change in tangent loss factor (tan d) with frequency (log x) of WO3 nano-particles at room temperature. Tangent loss factor (tan d) was obtained by the formula as mentioned in equation 1:
e00 ¼ e0 tand
ð1Þ
1 , C ¼ e0dA, e0 represents free space permittivity, A ðxRp C o Þ o represents electrode area and d represents the thickness of the sample. From the Fig. 2, it is clear that tangent loss versus frequency curves for both the samples (WO3 sintered at 500 °C and 800 °C) shows anomalous dielectric performance by showing higher values of tan d at lower frequency. The maximum loss was scrutinized due to the hopping frequency of electrons involved in it and becomes relatively identical to the frequency of the applied field. A continuous variation in maxima (xmax) with variation in sintering temperature of the samples indicates the jumping or hopping probability per unit time is varying continuously. With increase in frequency, the tangent loss factor decreases, possibly due to the space charge deviation that take place at grain boundaries with the effect of growth of charge carriers under the presence of an applied field.
where e00 ¼
3.2. Photocatalytic studies In order to study the photo-catalytic responses of WO3 photocatalyst, concentration of MB in the solution was measured by the UV–Vis spectrometer (Camspec) optical absorption peak at 664 nm, as noted with a certain absorption concentration standard curve. The de-coloration efficiency of WO3 photo-catalysts was evaluated using formula [8–9] cited in Eq. (2).
Efficiency ð%Þ ¼ ððC o C t ÞÞ=C o 100
ð2Þ
Where Co and Ct are respectively the original absorbance and absorption after ‘t’ time irradiation. Fig. 3 shows degradation profiles of MB dye (a) without catalyst (b) in the presence of WO3 (500 °C) (c) in the presence of WO3 (800 °C) (d) concentration verses time plot. It can be observed that WO3 calcined at 500 °C shows lesser degradation which is 86.8% in 220 min. in comparison with WO3 calcined at 800 °C which is 96.7% in 160 min. The better photocatalytic activity of WO3 was observed with WO3 calcined at 800 °C. This activity attributed
Fig. 2. Dielectric loss (tan d) verses frequency (log x) curves of WO3 calcined at 500 °C and 800 °C.
Please cite this article as: V. Luxmi and A. Kumar, Dielectric and photo-catalytic studies of rapidly synthesized m-WO3 nano-particles, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2020.01.544
V. Luxmi, A. Kumar / Materials Today: Proceedings xxx (xxxx) xxx
3
Fig. 3. Time reliant UV-visible absorption spectra for de-coloration of MB dye (a) without photo-catalyst (b) with WO3 (500 °C) (c) with WO3 (800 °C) (d) concentration verses time plot.
due to the crystallinity of WO3 which results in decreased number of defects and avoids electron-hole pairs recombination. Furthermore, other parameters like energy band gap (Eg) and specific surface area do not contribute much in photocatalytic activity due to small surface area and energy band gap values (Eg) of WO3 (500 °C) and (800 °C) [7].
Acknowledgements The authors are glad to honour the Director, NIT Kurukshetra for providing the Physics Department with scholarship and characterization equipments. References
4. Conclusions In the present work, WO3 nano-structures calcined at two different temperatures (500 °C and 800 °C) were successfully synthesized via co-precipitation method. Complex impedance spectroscopic activities of WO3 nano-particles is clearly visible in Cole-Cole plot (Nyquist plot) which reveals that with rise in calcining temperature, enhancement in conductivity with reduction in relaxation time takes place. Reduction in resistance and dielectric loss factor (tan d) is observed with calcining via plotting dielectric loss (tan d) versus frequency (log x). Photocatalytic results show that synthesized WO3 (800 °C) nano-particles possesses enhanced photocatalytic activity in degrading MB dye under visible light i.e. 96.7% in 160 min with rate constant k 0.01878. It is attributed due to efficient separation of electron-hole during photocatalytic activity. Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
[1] G.R. Bamwenda, H. Arakawa, The visible light induced photocatalytic activity of tungsten trioxide powders, J. Appl. Catal. A 210 (2001) 181–191. [2] W.J. Lee, Y.K. Fang, J.J. Ho, W.T. Hsieh, S.F. Ting, Effects of surface porosity on tungsten trioxide (WO3) films’ electrochromic performance, J. Electr. Mater. 29 (2000) 183–187. [3] H. Turkez, B. Cakmak, K. Celik, Evaluation of the potential in vivo genotoxicity of tungsten (VI) oxide nano powder for human health, J. Eng. Mater. 543 (2013) 89–92. [4] P. Broker, A.V. Salker, Photocatalytic degradation of textile azo dye over Ce1xSnxO2 series, J. Mater. Sci. Eng. B 133 (2006) 55. [5] R. Jiang, H. Zhu, X. Li, L. Xiao, Visible light photocatalytic decolourization of CI Acid Red 66 by chitosan capped CdS composite nanoparticles, J. Chem. Eng. 152 (2009) 537–542. [6] H. Zhu, R. Jiang, L. Xiao, Y. Chang, Y. Guan, X. Li, G. Zeng, Photocatalytic decolorization and degradation of Congo Red on innovative crosslinked chitosan/nano-CdS composite catalyst under visible light irradiation, J. Hazard. Mater. 169 (2009) 933–940. [7] D.S. Martínez, A. Martínez-De La Cruz, E.L. Cuéllar, Photocatalytic properties of WO3 nanoparticles obtained by precipitation in presence of urea as complexing agent, J. Appl. Catal. A 398 (2011) 179–186. [8] V. Luxmi, A. Kumar, Enhanced photocatalytic performance of m-WO3 and m-Fedoped WO3 cuboids synthesized via sol-gel approach using egg albumen as a solvent, J. Mater. Sci. Semicond. Process. 104 (2019) 104690. [9] A. Kumar, V. Luxmi, Novel green photo-catalyst ‘turmeric roots’ for pesticides degradation: preparation and characterizations, J. Mater. Lett. (2019) 127030.
Please cite this article as: V. Luxmi and A. Kumar, Dielectric and photo-catalytic studies of rapidly synthesized m-WO3 nano-particles, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2020.01.544