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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 samples synthesized at different temperatures: (a) and (b) 140 °C, nanospindle; (c) and (d) 160 °C, amorphous nanoparticle; (e) and (f) 180 °C, pseudo-nanodisk; (g) and (h) 200 °C, uniform nanodisk.
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Figure 3: SEM and TEM analysis of samples synthesized at different temperatures: (a) and (b) 140 °C, nanospindle; (c) and (d) 160 °C, amorphous nanoparticle; (e) and (f) 180 °C, pseudo-nanodisk; (g) and (h) 200 °C, uniform nanodisk.

Mentions: The morphology of α-Fe2O3 synthesized at different temperatures in an aqueous medium of anhydrous iron chloride and sodium silicate additive shows a series of distinct structures: nanospindle, amorphous nanoparticle, pseudo-multilayer nanodisk, and highly symmetrical multilayered nanodisk, as shown in figures 3(a)–(h). Interestingly, the various structures are in line with the corresponding XRD patterns, demonstrating a transformation that evolves with increasing synthesis temperature: from crystalline to amorphous and then to crystalline again. Dramatically, the corresponding TEM image of amorphous nanoparticles (figure 3(d)) shows a pseudo-spindle shape with a blunt tip, indicating that at this temperature range Ostwald ripening plays the key role in nucleation instead of oriented attachment [41, 42], which might be the main reason for the amorphous structure.


Facile synthesis of α -Fe 2 O 3 nanodisk with superior photocatalytic performance and mechanism insight
SEM and TEM analysis of samples synthesized at different temperatures: (a) and (b) 140 °C, nanospindle; (c) and (d) 160 °C, amorphous nanoparticle; (e) and (f) 180 °C, pseudo-nanodisk; (g) and (h) 200 °C, uniform nanodisk.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 3: SEM and TEM analysis of samples synthesized at different temperatures: (a) and (b) 140 °C, nanospindle; (c) and (d) 160 °C, amorphous nanoparticle; (e) and (f) 180 °C, pseudo-nanodisk; (g) and (h) 200 °C, uniform nanodisk.
Mentions: The morphology of α-Fe2O3 synthesized at different temperatures in an aqueous medium of anhydrous iron chloride and sodium silicate additive shows a series of distinct structures: nanospindle, amorphous nanoparticle, pseudo-multilayer nanodisk, and highly symmetrical multilayered nanodisk, as shown in figures 3(a)–(h). Interestingly, the various structures are in line with the corresponding XRD patterns, demonstrating a transformation that evolves with increasing synthesis temperature: from crystalline to amorphous and then to crystalline again. Dramatically, the corresponding TEM image of amorphous nanoparticles (figure 3(d)) shows a pseudo-spindle shape with a blunt tip, indicating that at this temperature range Ostwald ripening plays the key role in nucleation instead of oriented attachment [41, 42], which might be the main reason for the amorphous structure.

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.