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Facile synthesis of α -Fe 2 O 3 nanodisk with superior photocatalytic performance and mechanism insight

View Article: PubMed Central - PubMed

ABSTRACT

Intrinsic short hole diffusion length is a well-known problem for α-Fe2O3 as a visible-light photocatalytic material. In this paper, a nanodisk morphology was designed to remarkably enhance separation of electron-hole pairs of α-Fe2O3. As expected, α-Fe2O3 nanodisks presented superior photocatalytic activity toward methylene blue degradation: more than 90% of the dye could be photodegraded within 30 min in comparison with a degradation efficiency of 50% for conventional Fe2O3 powder. The unique multilayer structure is thought to play a key role in the remarkably improved photocatalytic performance. Further experiments involving mechanism investigations revealed that instead of high surface area, ·OH plays a crucial role in methylene blue degradation and that O·2− may also contribute effectively to the degradation process. This paper demonstrates a facile and energy-saving route to fabricating homogenous α-Fe2O3 nanodisks with superior photocatalytic activity that is suitable for the treatment of contaminated water and that meets the requirement of mass production.

No MeSH data available.


SEM and TEM analysis of α-Fe2O3 nanodisks synthesized at 200 °C within: (a), (b), and (c) 15 min; (d), (e), and (f) 30 min; (g), (h), and (i) 60 min. (j) and (k) Top-view and side-view HRTEM images, respectively (inset: FTT pattern).
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Figure 4: SEM and TEM analysis of α-Fe2O3 nanodisks synthesized at 200 °C within: (a), (b), and (c) 15 min; (d), (e), and (f) 30 min; (g), (h), and (i) 60 min. (j) and (k) Top-view and side-view HRTEM images, respectively (inset: FTT pattern).

Mentions: The morphology of α-Fe2O3 nanodisks synthesized with microwave irradiation for 15, 30, and 60 min is shown in figures 4(a)–(k). All nanodisks exhibit round shapes with a diameter of approximately 100 nm (figures 4(a), (d), and (g)) and multilayer structures with a thickness of approximately 60 nm (figures 4(c), (f), and (i)). These results agree with the particle size calculated from the XRD patterns. Figure 4(j) is the HRTEM image acquired from the top view of a single α-Fe2O3 nanodisk. The lattice fringes are aligned perfectly across the surface with a spacing of 0.25 nm corresponding to the (110) planes, confirming the highly crystalline α-Fe2O3. It is worth noting that each adjacent layer of the nanodisks is around 6 nm, as shown in the HRTEM side-view image (figure 4(k)). It is expected that this special multilayered structure would be favorable for the separation of excited electron-hole pairs since the thickness is close to the intrinsic diffusion length (2–4 nm). Therefore, the photodegradation performance is enhanced.


Facile synthesis of α -Fe 2 O 3 nanodisk with superior photocatalytic performance and mechanism insight
SEM and TEM analysis of α-Fe2O3 nanodisks synthesized at 200 °C within: (a), (b), and (c) 15 min; (d), (e), and (f) 30 min; (g), (h), and (i) 60 min. (j) and (k) Top-view and side-view HRTEM images, respectively (inset: FTT pattern).
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC5036498&req=5

Figure 4: SEM and TEM analysis of α-Fe2O3 nanodisks synthesized at 200 °C within: (a), (b), and (c) 15 min; (d), (e), and (f) 30 min; (g), (h), and (i) 60 min. (j) and (k) Top-view and side-view HRTEM images, respectively (inset: FTT pattern).
Mentions: The morphology of α-Fe2O3 nanodisks synthesized with microwave irradiation for 15, 30, and 60 min is shown in figures 4(a)–(k). All nanodisks exhibit round shapes with a diameter of approximately 100 nm (figures 4(a), (d), and (g)) and multilayer structures with a thickness of approximately 60 nm (figures 4(c), (f), and (i)). These results agree with the particle size calculated from the XRD patterns. Figure 4(j) is the HRTEM image acquired from the top view of a single α-Fe2O3 nanodisk. The lattice fringes are aligned perfectly across the surface with a spacing of 0.25 nm corresponding to the (110) planes, confirming the highly crystalline α-Fe2O3. It is worth noting that each adjacent layer of the nanodisks is around 6 nm, as shown in the HRTEM side-view image (figure 4(k)). It is expected that this special multilayered structure would be favorable for the separation of excited electron-hole pairs since the thickness is close to the intrinsic diffusion length (2–4 nm). Therefore, the photodegradation performance is enhanced.

View Article: PubMed Central - PubMed

ABSTRACT

Intrinsic short hole diffusion length is a well-known problem for α-Fe2O3 as a visible-light photocatalytic material. In this paper, a nanodisk morphology was designed to remarkably enhance separation of electron-hole pairs of α-Fe2O3. As expected, α-Fe2O3 nanodisks presented superior photocatalytic activity toward methylene blue degradation: more than 90% of the dye could be photodegraded within 30 min in comparison with a degradation efficiency of 50% for conventional Fe2O3 powder. The unique multilayer structure is thought to play a key role in the remarkably improved photocatalytic performance. Further experiments involving mechanism investigations revealed that instead of high surface area, ·OH plays a crucial role in methylene blue degradation and that O·2− may also contribute effectively to the degradation process. This paper demonstrates a facile and energy-saving route to fabricating homogenous α-Fe2O3 nanodisks with superior photocatalytic activity that is suitable for the treatment of contaminated water and that meets the requirement of mass production.

No MeSH data available.