Oxidation of Dodecanoate Intercalated Iron(II)–Iron(III) Layered Double Hydroxide to Form 2D Iron(III) (Hydr)oxide Layers

Abstract

A planar trioctahedral iron(II)-iron(III) hydroxide (green rust, GR) intercalated with dodecanoate (GR C12 ) has been oxidized by dioxygen to produce the corresponding planar iron(III) (hydr)oxide. The formulae of GR C12 and the final iron(III) product (oxGR C12 ) were determined to be Fe II 2.00 Fe III 1.00 (OH) 5.31 (C 12 H 23 O 2 ) 0.66 (SO 4 ) 0.51 and Fe III 3 O 2.18 -(OH) 3.13 (C 12 H 23 O 2 ) 0.56 (SO 4 ) 0.47 , respectively. oxGR C12 has the same planar layer structure as GR C12 , as revealed by identical powder X-ray diffraction patterns. The electrostatic interactions between the interlayer dodecanoate (C12) anions and the iron hydroxide planar layer were preserved during the oxidation, as shown by FTIR spectroscopy. The high positive charge in the hydroxide layer produced by the oxidation of iron(II) to iron(III) is partially compensated by the deprotonation of hydroxy groups, as shown by X-ray [a]

Single sheet iron oxide based films: electrochemical properties with in situ UV-vis measurement

“…3a) shows platelets with a lateral dimension of 50-200 nm similar to its parent layered iron(III) oxyhydroxide compound. 15 The suspension of nano-sized TBA dispersed SSI colloids shows a high optical absorption with a peak centred at 275 nm and a strong shoulder at 341 nm which are not observed in the bulk iron oxides (Fig. 4a).…”

“…Interestingly, the reverse reaction, oxidation of iron(II) to iron(III), then should take place with dehydroxylation as a consequence. 15 The n th PDDA/SSI lm is as electroactive as the rst one (Fig. 10b), and all the SSI fragments in one PDDA/SSI lm stay in electronic contact with each other due to close packing with possible water layers between them.…”

“…14 Such a layered material results from the oxidation of a layered dodecanoate intercalated iron(II)iron(III) hydroxide which is iso-structural with brucite (Mg(OH) 2 ). 15 Compared to other bulk iron oxide particles, SSI with a thickness of 1 nm (iron oxide layer plus adsorbed water) has the highest possible surface area to volume ratio due to the full exposure of all iron oxide sites. The manipulation of 2D nanosheets has been well-established using layer by layer (LBL) assembly, [16][17][18] and ultrathin lms of iron oxide nanoparticles have been assembled via the LBL electrostatic method [19][20][21] or the Langmuir-Blodgett method.…”

“…14,15 Thus, when E c ¼ À0.7 V (pH 12), the whole redox process is highly reversible without irreversible transformation to other iron oxide phases such as Fe 3 O 4 , HFeO 2À , and Fe(OH) 2 . In contrast, the spectra of other iron oxide lms cannot be restored to their original state aer the 1 st cathodic cycle which is likely to be caused by irreversible phase transformation to Fe 3 O 4 and/or Fe(OH) 2 3.…”

Cobalt: A must-have element for life and livelihood

“…Indeed, the expectation is that the ferrous–ferric oxyhydroxide fougerite, along with FeS, comprised the first barrier that kept the disequilibria between the alkaline hydrothermal solutions and the early carbonic ocean at bay, necessary for driving life’s onset ( 8 , 17 , 18 ). It is worth remarking here that fougerite can absorb and host long-chain carboxylic acids in its interlayers, acids that could be released to the alkaline vent on delamination ( 19 ).…”