The influence of precursors on phase evolution of nano iron oxides/oxyhydroxides: optical and magnetic properties

Abstract

The present investigation describes the evolution of nanoiron oxide/oxyhydroxide phases synthesized under identical conditions of precipitation using different starting reagents.

Crumpled sheet like graphene based WO3-Fe2O3 nanocomposites for enhanced charge transfer and solar photocatalysts for environmental remediation

“…6b. ) reveals the peaks at 223 and 487 cm -1 corresponds to A1g and the peaks at 242, 296, 336, 408, and 605 cm -1 corresponds to Eg vibrational modes of Fe 2 O 3, good agreement with previous reports [57,58]. (Fig.…”

Spectral and morphological characteristics of synthetic nanophase iron (oxyhydr)oxides

“…4. Positions of the Raman features are listed in Table 2 along with Raman data from the literature (Hanesch 2009;Das and Hendry 2011;Das et al 2013), and the origin and symmetry of each Raman transition, where available (Bersani et al 1999;Chamritski and Burns 2005;Jubb and Allen 2010;Rout et al 2014). Despite the fact that these nanophase sample spectra were acquired using low laser power, all of the diagnostic and a majority of the expected Raman peaks are visible.…”

“…Due to these complicating factors, multiple characterization techniques are required for definitive identification of nanophase samples (Wigginton et al 2007); yet very few studies have used multiple spectroscopic techniques to analyze the same samples of iron NPOs with known grain morphologies (size, shape, crystallinity). Syntheses of iron (oxyhydr)oxides are notably difficult to precisely duplicate (Lewis and Schwertmann 1979;Schulze 1984) and the resulting slight structural changes lead to morphological and spectral changes (Lu et al 2005;Heitjans et al 2007;Liu et al 2009;Rout et al 2014). Thus, analyzing the same samples by multiple techniques is essential in developing links between morphology and spectral features.…”

“…The position of the 6 A 1 → 4 T 1 transition as well as the VIS spectral maximum are indicated for each sample as these can often be used for mineral differentiation. Note that magnetite and maghemite can be easily differentiated by their VNIR spectra; however, this distinction may be lost in mixed-phase samples Table 2 Raman shift peak positions (cm −1 ) with those reported for bulk iron (oxyhydr) oxides Hanesch (2009) b Chamritski and Burns (2005) and references therein c Bersani et al (1999) d Jubb and Allen (2010) e Rout et al (2014) f Das and Hendry (2011) g Das et al (2013) Sklute et al Page 42 Table 3 MIR peak positions (cm −1 ) along with those reported for bulk iron (oxyhydr)oxides Sherman and Waite (1985) b Cornell and Schwertmann (2006) c Hunt et al (1971) d Bishop et al (2015) e Scheinost et al (1998)…”

Metal doped mesoporous FeOOH nanorods for high performance supercapacitors

“…In general, it was observed that the a-FeOOH phase was the major direct hydrolysis product. 5,[30][31][32][33][34] However, depending on the surface energetics, sizes and environment, different phases of Fe(III) oxides/oxyhydroxides/ hydroxides with addition of cobalt were formed in case of C1 and C2 samples. The C0 sample is the most stable a-Fe 2 O 3 phase but due to the addition of secondary metal ion cobalt, C1 and C2 evolved with a-FeOOH phase with lower surface energy.…”