Hematite porous architectures as enhanced air purification photocatalyst

Balbuena, José; Cruz-Yusta, Manuel; Cuevas, Ana; Martı́n, Francisco; Pastor, Adrián; Romero, R.; Sánchez, L.

doi:10.1016/j.jallcom.2019.05.113

Cited by 22 publications

(22 citation statements)

References 52 publications

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“…33-0664. ), indicating the formation of a single crystalline phase, as expected on the basis of previous studies [36,39,42] and literature [46,47,49,[51][52][53]57] as well. The average crystallite size (30.4 nm) was estimated from the FWHM (full width at half-maximum, β) of the most intense (104) peak, via the Scherrer formula, d = Kλβcosθ, with K = 0.9 and λ = 0.1541 nm.…”

Section: Physicochemical Properties Of the Nfssupporting

confidence: 88%

“…Although both types of NFs exhibited a hierarchical structure, in the absence of germanium (Figure 1e-g), the NFs consisted of interconnected rounded and smooth crystalline grains, about 65 nm in size [39]. The resulting coral-like architecture seems to be peculiar to electrospun iron oxide NFs, as it has been frequently observed regardless of the precursors utilized to prepare the spinnable solution and the heat treatment conditions [46][47][48][49][50][51][52][53]. Previous studies on NFs prepared under the same conditions [42] had revealed the single-crystal or quasi-single-crystal nature of the oxide grains, as well as the hollow section of the fibers that is due to the large temperature gradient along the radial direction experienced by the FeAc 2 -PAN NFs upon calcination [54].…”

Section: Physicochemical Properties Of the Nfsmentioning

confidence: 91%

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Effect of Germanium Incorporation on the Electrochemical Performance of Electrospun Fe2O3 Nanofibers-Based Anodes in Sodium-Ion Batteries

et al. 2021

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Fe2O3 and Fe2O3:Ge nanofibers (NFs) were prepared via electrospinning and thoroughly characterized via several techniques in order to investigate the effects produced by germanium incorporation in the nanostructure and crystalline phase of the oxide. The results indicate that reference Fe2O3 NFs consist of interconnected hematite grains, whereas in Fe2O3:Ge NFs, constituted by finer and elongated nanostructures developing mainly along their axis, an amorphous component coexists with the dominant α-Fe2O3 and γ-Fe2O3 phases. Ge4+ ions, mostly dispersed as dopant impurities, are accommodated in the tetrahedral sites of the maghemite lattice and probably in the defective hematite surface sites. When tested as anode active material for sodium ion batteries, Fe2O3:Ge NFs show good specific capacity (320 mAh g−1 at 50 mA g−1) and excellent rate capability (still delivering 140 mAh g−1 at 2 A g−1). This behavior derives from the synergistic combination of the nanostructured morphology, the electronic transport properties of the complex material, and the pseudo-capacitive nature of the charge storage mechanism.

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Section: Physicochemical Properties Of the Nfssupporting

confidence: 88%

Section: Physicochemical Properties Of the Nfsmentioning

confidence: 91%

Effect of Germanium Incorporation on the Electrochemical Performance of Electrospun Fe2O3 Nanofibers-Based Anodes in Sodium-Ion Batteries

et al. 2021

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“…Figures d–o and S6 provide an overview of the NF morphology, as resulting from TEM and HAADF-STEM microscopy. In sample NF-600 (Figure d,g,j,m), the NFs exhibit a coral-like structure, peculiar to electrospun hematite. ,− As sketched in Figure f, they are made up by round, smooth grains, attached to each other to form a large, porous 3D nanostructure (Figure b). The strong interaction between PAN (polymer) and FeAc 2 (metal oxide precursor) in the pristine solution is responsible for this architecture .…”

Section: Resultsmentioning

confidence: 99%

Structure, Defects, and Magnetism of Electrospun Hematite Nanofibers Silica-Coated by Atomic Layer Deposition

et al. 2020

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In the last years, hematite has been utilized in a plethora of applications. High aspect-ratio nanohematite and hematite/silica core–shell nanostructures are arousing growing interest for applications exploiting their magnetic properties. Atomic layer deposition (ALD) is utilized here to produce SiO2-coated α-Fe2O3 nanofibers (NFs) through two synthetic routes, viz. electrospinning/calcination/ALD or electrospinning/ALD/calcination. The number of ALD cycles (10–100) modulates the coating thickness, while the chosen route controls the final nanostructure. Porous and partially hollow NFs are produced. Their hierarchical structure and the nature and density of the lattice defects and strain are characterized by combining electron microscopy, diffraction, and spectroscopy techniques. The uncoated hematite NFs mostly have surface-related strain, which is attributed to oxygen vacancies/Fe2+ sites. ALD coating causes microstrain release and decrease of surface states. NFs calcined after ALD have extensive bulk strain, which is ascribed to the presence of dislocations throughout the volume of the NF grains. Bulk strain determines the remanent magnetization, whereas both surface and bulk strain influence the coercive field and the thermal behavior across the Morin temperature, including the magnetic memory effect. To the best of the authors’ knowledge, the correlation between lattice defects/strain and magnetic properties of SiO2-coated α-Fe2O3 NFs has never been reported before.

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“…1,2,8,18,21 Although various research works have been aimed at the development of De-NO x photocatalysts, 1,3,14 key problems still far from being completely overcome are related to the low activity and the generation of undesired/toxic byproducts, 1,5 in particular, the NO 2 intermediate. 6,13,20,22,23 Hence, an important goal to be fulfilled for an efficient NO x degradation, an actual open challenge, 2,4,10,[14][15][16]24 is the obtainment of a high selectivity toward harmless nitrates (NO 3 − ) as the major process products. 1,13,17,19,21 Over the last decade, semiconductor metal oxide nanosystems have been investigated as De-NO x photocatalysts, thanks to their favorable chemico-physical properties, relatively low cost, and good chemical stability.…”

Section: ■ Introductionmentioning

confidence: 99%

Tailored Co₃O₄-Based Nanosystems: Toward Photocatalysts for Air Purification

Fragoso

Barreca

Bigiani

et al. 2021

ACS Appl. Mater. Interfaces

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The adverse effects of NO x (NO + NO2) gases on the environment and human health have triggered the development of sustainable photocatalysts for their efficient removal (De-NO x ). In this regard, the present work focuses on supported Co3O4-based nanomaterials fabricated via chemical vapor deposition (CVD), assessed for the first time as photocatalysts for sunlight-activated NO oxidation. A proof-of-principle investigation on the possibility of tailoring material performances by heterostructure formation is explored through deposition of SnO2 or Fe2O3 onto Co3O4 by radio frequency (RF) sputtering. A comprehensive characterization by complementary analytical tools evidences the formation of high-purity columnar Co3O4 arrays with faceted pyramidal tips, conformally covered by very thin SnO2 and Fe2O3 overlayers. Photocatalytic functional tests highlight an appreciable activity for bare Co3O4 systems, accompanied by a high selectivity in NO x conversion to harmless nitrate species. A preliminary evaluation of De-NO x performances for functionalized systems revealed a direct dependence of the system behavior on the chemical composition, SnO2/Fe2O3 overlayer morphology, and charge transfer events between the single oxide constituents. Taken together, the present results can provide valuable guidelines for the eventual implementation of improved photocatalysts for air purification.

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Hematite porous architectures as enhanced air purification photocatalyst

Cited by 22 publications

References 52 publications

Effect of Germanium Incorporation on the Electrochemical Performance of Electrospun Fe2O3 Nanofibers-Based Anodes in Sodium-Ion Batteries

Effect of Germanium Incorporation on the Electrochemical Performance of Electrospun Fe2O3 Nanofibers-Based Anodes in Sodium-Ion Batteries

Structure, Defects, and Magnetism of Electrospun Hematite Nanofibers Silica-Coated by Atomic Layer Deposition

Tailored Co₃O₄-Based Nanosystems: Toward Photocatalysts for Air Purification

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Hematite porous architectures as enhanced air purification photocatalyst

Cited by 22 publications

References 52 publications

Effect of Germanium Incorporation on the Electrochemical Performance of Electrospun Fe2O3 Nanofibers-Based Anodes in Sodium-Ion Batteries

Effect of Germanium Incorporation on the Electrochemical Performance of Electrospun Fe2O3 Nanofibers-Based Anodes in Sodium-Ion Batteries

Structure, Defects, and Magnetism of Electrospun Hematite Nanofibers Silica-Coated by Atomic Layer Deposition

Tailored Co3O4-Based Nanosystems: Toward Photocatalysts for Air Purification

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Tailored Co₃O₄-Based Nanosystems: Toward Photocatalysts for Air Purification