Total Gibbs Free Energy Research Articles

Cu single atoms mediated multiple active site reconfiguration to trigger Dual-pathway nonradical peroxymonosulfate activation process

Developing atomically dispersed metal sites is vital to enhance the activation of peroxymonosulfate (PMS). However, for catalyst systems where single atoms and nanoclusters coexist, how to identify the independent and synergistic effects of atomic sites and investigate the possible coexistence of multiple activation mechanisms still remains a great challenge. Herein, CuSA/CoOx-CeO2 catalysts with Cu single atoms and CoOx nanoclusters were fabricated for PMS activation. The introduction of Cu single atoms led to the reconstruction and diversification of catalytic active sites of CoOx-CeO2. The synergy between CoOx nanoclusters and neighboring Cu single atoms in CuSA/CoOx-CeO2 catalyst led to the 1O2 pathway of PMS activation, while the isolated Cu atom induced the Cu(III) oxidation pathway. The introducing of adjacent Cu single atoms caused the redistribution of the site charges in CoOx nanoclusters, which enhanced the charge transfer and promoted the adsorption and activation behavior of PMS molecules. During the evolution of 1O2, the synergistic effect of Cu single atoms and CoOx nanoclusters increased the stability of the reaction intermediate state (*OO*SO3), reducing the total Gibbs free energy change (ΔG) required for 1O2 formation. Compared with the cooperative site, the isolated Cu-O4 sites exhibited stronger charge transfer capacity to PMS molecules and were more conducive to the activation of the local substrate electronic structure, facilitating the formation and stabilization of Cu(III)–OH metastable intermediates. Overall, this study demonstrated the importance about the construction of multi-site induced multipath coexisting PMS activation system and the accurate identification of active sites.

Thermodynamic analysis of MnWO4 as an oxygen carrier in a chemical looping scheme for hydrogen production

In the last few years, hydrogen has attracted much attention because of its importance in the transition to a sustainable energy system and its use as a raw material in many industrial processes. In this context, chemical looping is proposed as an alternative to traditional methane reforming processes, where methane is partially oxidized by the lattice oxygen of a solid oxygen carrier instead of using water or pure oxygen. This work presents a thermodynamic analysis of MnWO4 as an oxygen carrier and the compositions at equilibrium were calculated by minimizing the total Gibbs free energy of the system. To evaluate its possible integration into a chemical looping scheme, this study assesses the optimal reaction temperature and reactant molar ratio to attain high hydrogen yield while avoiding carbon formation. The findings suggest that temperatures exceeding 775°C and ratios above stoichiometry are necessary. For successful regeneration, air or water can be used. In the former case a stoichiometric ratio of 1.5:1 of O2 to MnO/W is required, while for the latter, an excess of water in necessary.

Unified non-fitting explicit formulation of thermodynamic properties for five compounds

The explicit formulations of the Gibbs free energy subject to the concerned species are useful to determine the conditions for minimizing the total Gibbs free energy of a system with a simple way. Here, we develop a unified non-fitting explicit formulation of the Gibbs free energy for five compounds, including N2O, ClBO, OBBr, HBO and HCN. The established Gibbs free energy formulation is correlative only with masses of atoms and experimental data of six molecular constants of triatomic molecules, and away from requirement of fitting a plenty of experimental spectroscopic data or calorimetric data in conventional empirical expressions. For five compounds under consideration, the average absolute deviations between the predicted Gibbs free energy values and the data provided in the National Institute of Standards and Technology (NIST) database are within the range of 0.098% to 0.146%. Employing the developed unified non-fitting Gibbs free energy formulation with high accuracy, the theoretically predicted values of the entropy, enthalpy, and isobaric heat capacity for the concerned five substances are acquired, and the coresponding average absolute deviations from the NIST data are within the ranges of 0.166% to 0.263%, 0.571% to 2.533%, and 1.059% to 1.936%, respectively.

Deciphering the structure of a distinctive trimodular cellulosomal licheninase (RfGH16_21), a family 16 glycoside hydrolase from Ruminococcus flavefaciens by computational and experimental methods

In order to know the insights of a unique naturally existing trimodular licheninase from GH16 family, sub-family 21 (RfGH16_21) from Ruminococcus flavefaciens, its structure was modeled to understand its functional relations to reveal information regarding modifying the enzyme for improved properties with enhanced catalytic efficiency. Homology modeling revealed three tandem repeats of β-jelly roll like folds linked by natural linkers. Catalytic pockets and the catalytically important amino acids in each tandem repeat of RfGH16_21 determined by multiple sequence alignment and structure superposition with its homologues indicated that two Glu residues are involved in a retaining-type of catalytic mechanism. Sequential molecular docking revealed maximum binding energy with mixed linked cellotriose showing that cellotriose is the lowest oligomeric hydrolysed product formed by the catalytic action of endo-β-1,3–1,4-glucanase. Molecular dynamic (MD) simulation of RfGH16_21-cellotriose complex confirmed the structural specificity of catalytic residues and increased stability of enzyme in presence of ligand as compared to simulated RfGH16_21 alone. The binding affinity of cellotriose towards the three tandem repeats of RfGH16_21 was also confirmed by calculating total binding Gibbs free energy, i.e. −100.8 ± 2.6 KJ/mol, by using g_mmpbsa tool. The stability of the protein was determined by protein melting analysis that showed Ca2+ and Mg2+ ions imparted structural stability to RfGH16_21. Dynamic light scattering analysis of RfGH16_21 showed monodispersity and hydrodynamic radius of 4.0 nm at 2.0 mg/mL protein concentration, which was comparable with the radius of gyration of 3.2 nm determined by MD simulation showing the protein to be in monomeric form. Communicated by Ramaswamy H. Sarma

Thermodynamic analysis of bio-oil model compounds to light hydrocarbon

The present work uses the total Gibbs free energy minimization approach to analyze the thermodynamic equilibrium analysis of bio-oil model compounds to light hydrocarbons. A mixture of model compounds was subjected to co-cracking with methanol and ethanol, and at a range of temperatures (300–1200 °C) and pressures (1–50 bars), the equilibrium compositions were calculated as a function of the hydroxypropanone-acetic acid-ethyl acetate/methanol ratio (HAEM) and the hydroxypropanone-acetic acid-ethyl acetate/ethanol ratio (HAEE). Possible reactions were analyzed, revealing that methane is the predominant product, followed by hydrogen, carbon monoxide, carbon dioxide, and propionic acid. The production of light hydrocarbons, including ethylene, ethane, propylene, and propane, was minimal. Notably, the co-reactant ethanol (HAEE 1:12) in the co-cracking of bio-oil model compounds demonstrated a significant effect on the production of methane, ethylene, and propylene at 1 bar pressure and 300 °C (for methane production) and 1200 °C (for ethylene and propylene production).

Physics-informed machine learning and stray field computation with application to micromagnetic energy minimization

We study the full 3d static micromagnetic equations via a physics-informed neural network (PINN) ansatz for the continuous magnetization configuration. PINNs are inherently mesh-free and unsupervised learning models. In our approach we can learn to minimize the total Gibbs free energy with additional conditional parameters, such as the exchange length, by a single low-parametric neural network model. In contrast, traditional numerical methods would require the computation and storage of a large number of solutions to interpolate the continuous spectrum of quasi-optimal magnetization configurations. We also consider the important and computationally expensive stray field problem via PINNs, where we use a basically linear learning ansatz, called extreme learning machines (ELM) within a splitting method for the scalar potential. This reduces the stray field training to a linear least squares problem with precomputable solution operator. We validate the stray field method by means of numerical example comparisons from literature and illustrate the full micromagnetic approach via the NIST μMAG standard problem #3.

Theoretical Study of Hydroxylation of α- and β-Pinene by a Cytochrome P450 Monooxygenase Model

Previous studies on biocatalytic transformations of pinenes by cytochrome P450 (CYP) enzymes reveal the formation of different oxygenated products from a single substrate due to the multistate reactivity of CYP and the many reactive sites in the pinene scaffold. Up until now, the detailed mechanism of these biocatalytic transformations of pinenes have not been reported. Hereby, we report a systematic theoretical study of the plausible hydrogen abstraction and hydroxylation reactions of α- and β-pinenes by CYP using the density functional theory (DFT) method. All DFT calculations in this study were based on B3LYP/LAN computational methodology using the Gaussian09 software. We used the B3LYP functional with corrections for dispersive forces, BSSE, and anharmonicity to study the mechanism and thermodynamic properties of these reactions using a bare model (without CYP) and a pinene-CYP model. According to the potential energy surface and Boltzmann distribution for radical conformers, the major reaction products of CYP-catalyzed hydrogen abstraction from β-pinene are the doublet trans (53.4%) and doublet cis (46.1%) radical conformer at delta site. The formation of doublet cis/trans hydroxylated products released a total Gibbs free energy of about 48 kcal/mol. As for alpha pinene, the most stable radicals were trans-doublet (86.4%) and cis-doublet (13.6%) at epsilon sites, and their hydroxylation products released a total of ~50 kcal/mol Gibbs free energy. Our results highlight the likely C-H abstraction and oxygen rebounding sites accounting for the multi-state of CYP (doublet, quartet, and sextet spin states) and the formation of different conformers due to the presence of cis/trans allylic hydrogen in α-pinene and β-pinene molecules.

TELP theory: Elucidating the major observations of Rieger et al. 2021 in mitochondria

The transmembrane-electrostatically localized protons (TELP) theory may represent a complementary development to Mitchell's chemiosmotic theory. The combination of the two together can now excellently explain the energetics in mitochondria. My calculated transmembrane-attractive force between an excess proton and an excess hydroxide explains how TELP may stay within a 1-nm thin layer at the liquid-membrane interface. Consequently, any pH sensor (sEcGFP) located at least 2–3 nm away from the membrane surface will not be able to see TELP. This feature as predicted from the TELP model was observed exactly in the experiment of Rieger et al., 2021. In contrast to their belief “the Δp at ATP synthase is almost negligible under OXPHOS conditions”, I find, when TELP activity is included in the energy calculations, there is plenty of total protonic Gibbs free energy (ΔGT) well above the physiologically required value of −24.5 kJ mol−1 to drive ATP synthesis through FoF1-ATP synthase.

Structural and functional insights into the glycoside hydrolase family 30 xylanase of the rumen bacterium Ruminococcus flavefaciens

The family 30 glycoside hydrolase (RfGH30) from Ruminococcus flavefaciens expressing xylanase activity was homology modeled. The structure revealed a (β/α)8 TIM barrel topology along with an associated ‘side β-structure’. Secondary structure analysis by circular dichroism displayed 28.09% α-helices and 21.02% β-strands, which corroborated with the prediction results. Multiple Sequence Alignment and structure superposition of RfGH30 with its homologue indicate that Glu200 and Glu302 are the catalytic residues displaying a retaining-type of catalysis. Molecular Dynamics (MD) simulation of RfGH30 confirmed the structural compactness and steadiness of modeled structure. Molecular docking studies showed maximum binding affinity with xylobiose that was corroborated by the total binding Gibbs free energy of -160.5 kJ/mol calculated by g_mmpbsa tool. MD simulation of RfGH30-xylobiose confirmed the structural specificity of catalytic residues and its increased stability in presence of ligand. Small angle X-ray scattering (SAXS) analysis of RfGH30 confirmed its monodispersed, fully folded and elongated structure in solution form. Dummy atom model revealed monomeric form of RfGH30 at 2.8 mg/ml, while at 4 mg/ml as dimer. Dynamic light scattering analysis of RfGH30 showed monodispersity and increase in hydrodynamic radius (Rh) from 2.0 to 4.0 mg/mL, displaying possible dimerization of RfGH30 at 4.0 mg/mL as corroborated by SAXS analysis. The lowered zeta potential of RfGH30 at 4 mg/mL also indicated the formation of a dimer.

Physical Insight into the Conditions Required in the Solid-Phase Molecular Self-Assembly of SDS Revealed by Coarse-Grained Molecular Dynamics Simulation.

Molecular self-assembled materials have attracted considerable interest in recent years. As part of the efforts to overcome the shortcoming that the solution-based methods were hardly applicable in preparing bulk macroscopic molecular self-assemblies, Yan [ CCS Chem. 2020, 2, 98-106] developed a strategy of solid-phase molecular self-assembly (SPMSA) that allows scaling up the generation of massive supramolecular films. It is highly desired to understand the physical insight into the SPMSA at a molecular level. Here, in combination with the experimental study, we report molecular dynamics (MD) simulations on the SPMSA of the surfactant sodium dodecyl sulfate (SDS) using a coarse-grained method with the Martini force field model. The MD simulations clearly manifest that a small amount of water is required to endow the SDS molecules with sufficient mobility to self-assemble, and the smaller size of the preassembled SDS particles favors their further fusion into mesophases by reducing the total surface Gibbs free energy, while the smaller interparticle distance decreases the time for the particle fusion. The simulation results agree well with the conditions required in the experiment, confirming that SMPSA is a free-energy-favored process leading to bulk self-assembled materials.

DFT study of 6-amino-3-(1-hydroxyethyl) pyridine-2,4-diol (AHP) adsorption on Coronene

• Dissemination of charges all over the molecular system is a confirmation of chemical enhancement. • Increasing the interaction with doping (N, B) Corenene complexes. • Coronene sheets could be a good contestant for drug discovery. • Solvent effects of AHP in quantum complexes greatly affect the stability of the complex. Adsorption of 6-amino-3-(1-hydroxyethyl) pyridine-2,4-diol (AHP) on Corenene and NNP (Nitorgens doped on para position), NBP (Nitrogen and Boron on ortho position), and NBO (Nitrogen and Boron on ortho position) doped Coronene has been studied with Density Functional Theory (DFT) and Time-dependent DFT simulations. The bond distance, adsorption energy, charge analysis, frontier molecular orbital analysis (FMO), dipole moment, AIM, RGD, UV–Vis, and density of states (DOS) along with their solvent effect has been considered while conducting this study. The nucleophilic part of the AHP act as an electron-donating and the Corenene sheet acts as an electron acceptor and resulting and intermolecular interaction vis nucleophilic and electrophilic region approach. The total Gibbs free ( ΔG ) adsorption energy of AHP was calculated to be −5.07, −10.51, and −11.22 kcal/mole respectively to the CC, BBP, and NNP graphene quantum dots. Moreover, the change in interaction energy ( ΔE ) and change of enthalpy ( ΔH ) were found to be −3.66 and −2.75, –22.13 and −21.44, −20.94 and −20.08 kcal/mole correspondingly. Our calculations show that AHP–NNP complex is the most stable complex among the other studies system.

Bir Florlu Aminoimidazolin Olan Midaflur'un Karşılaştırmalı Kuantum Kimyasal Analizi

Inspired by the striking achievements of fluorine-containing heterocyclic compounds in pharmaceutical chemistry, in this study quantum chemical calculations were carried out on the midaflur compound, which has skeletal-muscle relaxant and central nervous system (CNS) depressant properties. First of all, the total energy (ΔETotal), enthalpy (ΔH), and Gibbs free energy (ΔG) values for both tautomeric structures of midaflur were calculated and it was determined which form was more stable and the rest of the study was continued on this structure. For the stable amino form, the HF method and B3LYP/B3PW91 DFT functionals with different basis sets were used in order to examine the geometric parameters. The results were found to be in good agreement with the experimental values given in the literature. Furthermore, FT-IR analysis, Mulliken population analysis, frontier molecular orbital (FMO) analysis, natural bond orbital (NBO) analysis, nonlinear optical (NLO) properties, and electrostatic surface properties were studied in detail. In another part of the study, the logPow (logarithm of the n-octanol/water partition coefficient) value, which is the numerical expression of the lipophilicity of a drug for entry into the CNS, was estimated for midaflur. For this purpose, the calculations were repeated for the water and n-octanol phases using the universal solvation model based on density (SMD) for all the methodologies used in this study, and the free energies of solvation were predicted. It was concluded that the predictive power of the computational methods increased in the order of HF < B3PW91 < B3LYP.

Bio-additives from glycerol acetylation with acetic acid: Chemical equilibrium model

In this work, the chemical equilibrium of glycerol (G) acetylation with acetic acid (AA) to form mono- (MAG), di- (DAG) and tri- (TAG) acetylglycerols has been studied. These compounds are biodegradable and renewable options as high-quality bio-additives to improve the antiknock properties and the viscosity of fuels and biofuels.Due to the absence of thermodynamic data, the physicochemical and thermodynamic properties of the compounds were determined, such as the specific heat, and the enthalpy and entropy of formation, by employing a second-order group-additivity predictive method. The values obtained were validated with few experimental data available in the literature (298 K, 101.325 kPa), showing differences in the range 0.2–8.9%.The compositions at equilibrium were calculated by minimizing the total Gibbs free energy of the system and considering the non-ideality of the liquid phase. For this purpose, different temperatures (350–500 K), reactant molar ratios (1–12) and initial water contents (0 and 40 wt%) were studied. The results revealed the global exothermicity of the system, showing that total glycerol conversion (∼100%) and high yields to TAG (>90%) can be achieved in the 350–500 K range by employing AA:G molar ratios between 9 and 12. As the presence of water in the glycerol solution produces a decrease of the glycerol conversion and selectivity to TAG, its removal from the reaction medium should be considered. A comparison between our results with the reported data based on different catalytic systems indicates that this model could successfully describe the chemical equilibrium of the system.

Solid dispersions of quercetin-PEG matrices: Miscibility prediction, preparation and characterization

Quercetin is a bioflavonoid compound with low water solubility in both foods and the gastrointestinal tract, which limits the exploitation of its health-promoting properties. This study aims to formulate solid dispersions (SDs) of quercetin with hydrophilic polyethylene glycol PEG matrices, using the melt-mixing method, to improve the dissolution and antioxidant activity of quercetin. Initially, the total Gibbs free energy for different binary mixtures was modelled to predict the miscibility of the compounds. Then, the physicochemical properties of the formulated SDs were characterised and dissolution tests and antioxidant activity measurements were performed in vitro to evaluate the improved profiles and antioxidant activity of the SDs developed. The group contribution methods of Hoy and Van Krevelen and Hoftyzer, used for PEG solubility parameter calculations, presented a suitable prediction of interaction and miscibility behaviour. The results suggested the presence of amorphous quercetin precipitates in the crystalline matrix of PEG 4000 and PEG 6000, and the formation of an amorphous SD between quercetin and PEG 1000. These formulations achieved good radical scavenging activity and better dissolution, especially the quercetin-PEG 1000 SDs.

Thermo-electrochemical modeling of oxygen ion-conducting solid oxide fuel cells with internal steam reforming in the water-energy nexus

The precise estimation of chemical equilibrium state is highly crucial when simulating electrochemical and thermodynamic aspects of oxygen ion-conducting solid oxide fuel cells (SOFC). One way to determine the equilibrium state of an internal reforming solid oxide fuel cell system is to compute the total Gibbs free energy of the system (G) and then, adjust the molar amounts of each substance, subject to element balances, so as to minimize G. Multi-dimensional optimization algorithms can be used for this purpose. In this paper, a powerful analytical solution method called Lagrange's method of undetermined multipliers is used for estimating the chemical equilibrium state. The effects of each current density, reaction temperature and pressure of the stack, and fuel and carbon dioxide utilization ratios on the voltage losses and output voltage and power of the stack, efficiency, and molar portions of the exhaust chemical species in anode and cathode, are investigated. The solid oxide fuel cell stack simulations by Lagrange's method at a definite state shows an efficiency of 54.6% and output power of 158.3 kW.

Hydrogen production from steam and dry reforming of methane-ethane-glycerol: A thermodynamic comparative analysis

Glycerol is produced as a by-product waste during the biodiesel manufacturing process. In recent researches, glycerol has been extensively studied for its potential to be converted into higher value-added compounds because it is renewable and bioavailable compound to reduce the high biodiesel production cost. As a result, various methods and technologies, such as steam reforming and dry reforming, were utilized to convert glycerol to higher value added products. The straightforward route of dry and steam reforming techniques uses carbon dioxide and other greenhouse gases to create added-value products like syngas, which may be considered renewable alternatives to fossil fuels as global CO2 emission issues get higher and near-uncontrollable. Therefore, this article presents a novel thermodynamic equilibrium analysis of steam and dry reforming with methane-ethane-glycerol mixture based on the total Gibbs free energy minimization method for hydrogen generation. Equilibrium product compositions were determined as a function of molar ratio between H2O/methane-ethane-glycerol (WMEG) from 1:1 to 12:1 and CO2/methane-ethane-glycerol (CMEG) from 1:1 to 12:1 for steam and dry reforming respectively, where the molar basis of the methane-ethane-glycerol mixture is 1:1:1. The reforming temperatures are ranged from 573 K to 1273 K at atmospheric pressure of 1 bar. The production trends of H2, CO, CO2, CH4 and C were compared between both reforming of glycerol. From to the result of the study, the optimal operating parameter for the highest hydrogen production was under steam reforming with WMEG of 3:1 at 1273 K and zero carbon deposition is achieved. In comparison with CO and CO2 production, dry reforming produced higher yields than steam reforming. Furthermore, a significant increment of hydrogen production was not observed at higher ratios of WMEG and CMEG. Steam reforming inhibited the carbon formation thermodynamically better than dry reforming.

Reliable estimate of minimum miscibility pressure from multiple possible EOS models for a reservoir oil under data constraint

Multiple Equation of State (EOS) models are possible for a reservoir oil if limited laboratory data is used in the EOS model development; each EOS model has its own predicted minimum miscibility pressure (MMP) value with unknown reliability. This article presents a novel approach to estimate a reliable MMP value using the multiple MMP values calculated from multiple EOS models developed with limited laboratory data such as bubble point and density at bubble point. MMP predicted using the proposed approach has better accuracy than the estimated MMP from an EOS model developed using a large set of data at the regression stage. Each possible EOS model for a reservoir oil has a specific set of values of total Gibbs free energy of mixing (g) at bubble point and predicted MMP for a given injection gas. The MMP estimate is developed using the trend of g versus MMP (predicted) from multiple EOS models in the proposed approach. The AARD in MMP prediction for 22 oils is 5.21% using SRK EOS and 6.65% using PR EOS, which is lower than the earlier approach (7.6%) that uses all PVT, swelling test, and multi-contact test data in EOS model development.

Application of Polarisable Continuum Modelling to assess Minoxidil solubility in mixed solvents

ABSTRACT Experimental solubility of minoxidil was obtained in binary aqueous mixtures of ethanol, methanol and acetonitrile at 298.2 K. The effects of pH and micellisation were investigated on the solubility of the drug. Experimental solubility data was correlated by three co-solvency models, i.e. Yalkowsky, CNIBS/R-K, and the modified Wilson model. Density functional theory and hybrid functional B3LYP method was used with Polarisable Continuum Model (PCM) to correlate the experimental solubility data in various mass fractions of the binary solvent mixtures. We report the results of solute–solvent interaction energy as free energy of solvation (∆G sol ) of minoxidil in various mass fractions of ethanol + water mixtures. Total electrostatic energy, dipole moment, total Gibbs free energy and dielectric constant (ε) of minoxidil were also investigated.

Confinement of all-inorganic perovskite quantum dots assembled in metal-organic frameworks for ultrafast scintillator application.

Nucleation and growth of quantum dots (QDs) are thermodynamic processes driven by the total Gibbs free energy change (ΔG). We discuss the nucleation and growth theory of perovskite quantum dots (PeQDs) inside a metal-organic framework (MOF) as a strong constraint framework, which can effectively confine the size of QDs below 3 nm and achieve a scintillator with an ultra-fast transient lifetime of fluorescence. Therefore, based on the requirements for the optical properties of ultra-fast scintillation materials, two kinds of suitable MOFs (UiO-67-bpy and MIL-101(Cr)) were selected for synthesis. The method of 'ship-in-bottle' was adopted to embed perovskite quantum dots CsPbBrCl2 into MOF cages to form PeQDs@MOF composite materials, which is different from the one-pot method. In order to further improve the stability of PeQDs@MOF, polystyrene was used to cure the composite scintillator, which can resist exposure to UV light and withstand the ISO level 4 test, with the fastest transient lifetime of 2.13 ns and a fluorescence emission wavelength of 445 nm.

Optimized conditions for reduction of iron (III) oxide into metallic form under hydrogen atmosphere: A thermodynamic approach

Incomplete reduction of Fe2O3(s) iron oxide into metallic Fe(s), under hydrogen, is a challenge for iron-based catalysts limiting their industrialization for methane reforming or decomposition. This work provides thermodynamic models generated using the HSC 7.1 Chemistry software, based on minimization of total Gibbs free energy and provides amount of species resulting from the reduction of iron oxide under hydrogen. Molar ratios of Fe2O3 to H2(g) were varied from stoichiometric till hydrogen excess. An optimum molar ratio for highest reduction degree of iron oxides into metal was defined. Results show that direct reduction of Fe2O3(s) into Fe(s) is not possible, but a series of H2-induced reduction steps along with other side-reactions take place yielding, partially reduced iron oxides species. An optimized Fe2O3:H2 molar ratio exceeding 0.25:3 is needed to favor reduction of FeO(s) into Fe(s)0. For validation, simulated values were compared with experimental ones from literature (reduced amounts of iron oxide).