Fougerite and FeII–III hydroxycarbonate green rust; ordering, deprotonation and/or cation substitution; structure of hydrotalcite-like compounds and mythic ferrosic hydroxide

Génin, J.‐M. R.; Aissa, R.; Géhin, Antoine; Abdelmoula, Mustapha; Benali, O.; Ernstsen, Vibeke; Ona-Nguéma, Georges; Upadhyay, Chandan; Ruby, Christian

doi:10.1016/j.solidstatesciences.2005.02.001

Cited by 99 publications

(93 citation statements)

References 34 publications

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“…As previously mentioned, green rust of the kind to be precipitated at the interface between the alkaline hydrothermal solution and acidulous phosphate and iron-bearing ocean water is likely to comprise [Fe 8 ) with the obligate intercalation of anions to maintain charge balance [160][161][162][163][164][165]. Such a nanocryst may have acted as the pseudo enzyme driving phosphate condensation in lieu of the membrane helices [100,165,167 -169].…”

Section: A Pyrophosphatase Engine: Chemiosmosis For Freementioning

confidence: 99%

The inevitable journey to being

Russell

Nitschke²,

Branscomb

2013

Phil. Trans. R. Soc. B

121

159

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Life is evolutionarily the most complex of the emergent symmetry-breaking, macroscopically organized dynamic structures in the Universe. Members of this cascading series of disequilibria-converting systems, or engines in Cottrell's terminology, become ever more complicated—more chemical and less physical—as each engine extracts, exploits and generates ever lower grades of energy and resources in the service of entropy generation. Each one of these engines emerges spontaneously from order created by a particular mother engine or engines, as the disequilibrated potential daughter is driven beyond a critical point. Exothermic serpentinization of ocean crust is life's mother engine. It drives alkaline hydrothermal convection and thereby the spontaneous production of precipitated submarine hydrothermal mounds. Here, the two chemical disequilibria directly causative in the emergence of life spontaneously arose across the mineral precipitate membranes separating the acidulous, nitrate-bearing CO 2 -rich, Hadean sea from the alkaline and CH 4 /H 2 -rich serpentinization-generated effluents. Essential redox gradients—involving hydrothermal CH 4 and H 2 as electron donors, CO 2 and nitrate, nitrite, and ferric iron from the ambient ocean as acceptors—were imposed which functioned as the original ‘carbon-fixing engine’. At the same time, a post-critical-point (milli)voltage pH potential (proton concentration gradient) drove the condensation of orthophosphate to produce a high energy currency: ‘the pyrophosphatase engine’.

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Section: A Pyrophosphatase Engine: Chemiosmosis For Freementioning

confidence: 99%

The inevitable journey to being

Russell

Nitschke²,

Branscomb

2013

Phil. Trans. R. Soc. B

121

159

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“…These trivalent metal cations are knownt os erve as nucleation sites that lead to the formationo fs maller particles. [10] The higher crystallinity of FeMgFe-and FeMgGa-LDHs is likelya ssociated with the comparable ionicr adii of all cations in these compounds, opposed to the much smaller Al 3 + ion, which, in addition to thes ize effect, might lead to distortions in the LDH lattice.H owever,t he nature of the chosen trivalent cations has no effect on the interlayerd istance as evidenced by the absence of as hift of the 003 reflections. [11] According to the PXRD patterns of the calcined samples, the strategy of introducing Fe 2 + as ar edox active speciesi nto the LDH structure leads to as uccessful transformation into the desired spinel phase upon thermalt reatment.…”

Section: Textural Propertiesmentioning

confidence: 99%

Ammonia Decomposition and Synthesis over Multinary Magnesioferrites: Promotional Effect of Ga on Fe Catalysts for the Decomposition Reaction

et al. 2017

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Magnesioferrite (MgFe2O4)‐derived Mesoporous spinels of the type MgFeM3+O4 with M3+=Fe, Al, and Ga obtained upon calcination of hydrotalcite‐like compounds were investigated in the ammonia decomposition reaction at 1 bar and the synthesis of ammonia at 90 bar. The corresponding precursors were synthesized by co‐precipitation at 50 °C and constant pH of 10.5. N2 physisorption, PXRD, HR‐TEM, H2‐TPR, and NH3‐TPD were applied in order to obtain information about the textural, (micro‐)structural, solid‐state kinetics in reducing atmosphere, and adsorption properties of the samples. While phase‐pure layered double hydroxides (LDHs) were obtained for Al and Ga, magnesioferrite as the desired oxide phase and a low fraction of magnetite were formed besides the targeted precursor phase during co‐precipitation in the presence of Fe2+ and Fe3+ species. Reduction of the binary and ternary magnesioferrites occurs via two consecutive reactions. Only the second stage is shifted towards higher temperatures after incorporation of Al and Ga. The latter element boosts the catalytic decomposition of ammonia, yielding a 2‐fold and 5‐fold higher conversion at 500 °C compared to the samples containing Fe3+ and Al3+ species, respectively. In situ XRD measurements showed that this unprecedented promotional effect is related to the generation of (Fe, Ga)Fe3N. This phase, however, is detrimental for the synthesis of ammonia at elevated pressures in which the binary system outperforms the ternary spinels, yielding 30 % of the activity obtained with a highly promoted Fe‐based industrial catalyst.

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“…[38] There is an interdependence between the redox potential and the pH of green rusts: oxidation is promoted by deprotonation in alkaline conditions, while the reverse is true of acid conditions where protonation supports reduction. [17] These factors prompted Génin and his collaborators to remark, "Among all compounds containing FeII ions that can play the reservoir of reducing species, the FeII−III oxyhydroxysalts commonly denominated green rusts … constitute an unmatchable compound due to their redox flexibility. [180] As might be expected, solid state reductions of oxidized green rusts can also be driven electrochemically, resulting again in a highly reduced but still morphologically recognizable double layer hydroxide ([Fe II 6(OH)10][CO3.2H2O]) ( Figure 2).…”

Section: Green Rust -The First Organizing Nanoengine Of Life?mentioning

confidence: 99%

“…[15,16] That green rust is capable of conformational changes during oxidative-reductive and protonation-deprotonation oscillations lends itself to such investigations. [7,17,18,19] We also speculate on the crucial steps taken toward what must have been the break-out metabolism and an organic takeover of the mineral precursor disequilibrium or 'free energy' converters, as they acquire organic frameworks in a process that we have called 'minerobiolization'. We then review the status of efforts to test these and related ideas bearing on the issue and conclude with a rather long list of falsifiable predictions of the submarine AHV as it now stands!…”

Section: Introductionmentioning

confidence: 99%

Green Rust: The Simple Organizing ‘Seed’ of All Life?  <strong> </strong>

Russell

2018

Preprint

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The most important problem of synthetic biology is…the reduction of carbonic acid. and Without the idea of spontaneous generation and a physical theory of life, the doctrine of evolution is a mutilated hypothesis without unity or cohesion.[1] Leduc, [1]Abstract: Korenaga and coworkers present evidence to suggest that 4.3 billion years ago the Earth's mantle was dry and water filled the ocean to twice its present volume.[2] CO2 was constantly exhaled during the mafic to ultramafic volcanic activity associated with magmatic plumes that produced the thick, dense and relatively stable oceanic crust. In that setting two distinct major types of sub-marine hydrothermal vents were active: ~400°C acidic springs whose effluents bore vast quantities of iron into the ocean, and ~120°C, highly alkaline and reduced vents exhaling from the cooler, serpentinizing crust at some distance from the heads of the plumes. When encountering the alkaline effluents, the iron from the plume head vents precipitated out forming mounds likely surrounded by voluminous exhalative deposits similar to the banded iron formations known from the Archean. These mounds and the surrounding sediments likely comprising nanocrysts of the variable valence FeII/FeIII oxyhydroxide, green rust. The precipitation of green rust, along with subsidiary iron sulfides and minor concentrations of Ni, Co and Mo in the environment at the alkaline springs may have established both the key bio-syntonic disequilibria, and the means to properly make use of them -those needed to drive the essential inanimate-to-animate transitions that launched life. In the submarine alkaline vent model for the emergence of life specifically it is first suggested that the redox-flexible green rust microcrysts spontaneously formed precipitated barriers to the complete mixing of carbonic ocean and alkaline hydrothermal fluids, barriers that created and maintained steep ionic disequilibria; and second, that the hydrous interlayers of green rust acted as 'engines' that were powered by those ionic disequilibria and drove essential endergonic reactions. There, aided by sulfides and trace elements acting as catalytic promoters and electron transfer agents, nitrate could be reduced to ammonia and carbon dioxide to formate, while methane may have been oxidized to methyl and formyl groups. Acetate and higher carboxylic acids could then have been produced from these C1 molecules and aminated to amino acids, and thence oligomerized to offer peptide nests to phosphate and iron sulfides and secreted to form primitive amyloid-bounded structures, leading conceivably to protocells.

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Fougerite and FeII–III hydroxycarbonate green rust; ordering, deprotonation and/or cation substitution; structure of hydrotalcite-like compounds and mythic ferrosic hydroxide

Cited by 99 publications

References 34 publications

The inevitable journey to being

The inevitable journey to being

Ammonia Decomposition and Synthesis over Multinary Magnesioferrites: Promotional Effect of Ga on Fe Catalysts for the Decomposition Reaction

Green Rust: The Simple Organizing ‘Seed’ of All Life?  <strong> </strong>

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Fougerite and FeII–III hydroxycarbonate green rust; ordering, deprotonation and/or cation substitution; structure of hydrotalcite-like compounds and mythic ferrosic hydroxide

Cited by 99 publications

References 34 publications

The inevitable journey to being

The inevitable journey to being

Ammonia Decomposition and Synthesis over Multinary Magnesioferrites: Promotional Effect of Ga on Fe Catalysts for the Decomposition Reaction

Green Rust: The Simple Organizing &lsquo;Seed&rsquo; of All Life?&nbsp;&nbsp;<strong> </strong>

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Green Rust: The Simple Organizing ‘Seed’ of All Life? <strong> </strong>