Ratio Of H2O Research Articles

Molecular hydrogen storage in binary H2-CH4 clathrate hydrates

Clathrate hydrate has emerged as a promising candidate for hydrogen storage, but the major challenge is the high pressure required for its formation. The addition of natural gas can significantly reduce the formation pressure, but also can improve the energy density. In this work, we estimated the hydrogen storage capacity of the H2-CH4 binary hydrate by performing the first-principles calculations and simulations. The thermodynamical and mechanical stability of the hydrate was studied as a function of the cage occupancy of both 512 and 51264 cages. For the most stable structure, the molar ratio of H2 and H2O is 0.353:1. The H2-CH4 binary hydrate can maintain its structure during dynamics under the moderate temperature and pressure. The self-preservation effect was observed at ∼270 K, which can be used for the hydrogen storage and transport. These findings provide a better understanding of the mixed hydrate as a viable hydrogen storage technology, which could enable us to achieve a sustainable hydrogen economy.

Three-dimensional modeling of Venus photochemistry and clouds

We present here three-dimensional simulations of the Venus photochemistry and clouds from the ground to the bottom of the thermosphere. For that purpose, we have implemented a state-of-the-art photochemical and equilibrium cloud model in the Venus Planetary Climate Model (Venus PCM). The interactive coupling between dynamics, radiation, chemistry and clouds allows a comprehensive description of the CO2, CO, sulfur, chlorine, oxygen, and hydrogen species, with tracking of the condensed phase. Regarding the clouds, the Venus PCM calculates the composition, number density, and sedimentation rates of the binary H2SO4-H2O liquid aerosols, based on observed altitude-dependent size distributions. The article describes in detail the new components implemented in the Venus PCM. It then presents an overview of the results concerning clouds and atmospheric chemistry, which are compared with a wide range of observations. The modeled cloud characteristics and vertical profiles of minor species are found to be in broad agreement with most of the measurements available between 30 and 100 km. In particular, the Venus PCM reproduces the steep decrease of H2O and SO2 mixing ratio inside the cloud layer, as well as the observed vertical distribution of species well identified above the clouds, such as CO and O3. The model also agrees with the ground-based measurements of HCl, but not with the conflicting HCl vertical profiles derived from Venus Express. On the quasi-horizontal plane, latitudinal contrasts in the modeled trace species mostly result from the Hadley-type mean meridional circulation. Large-scale longitudinal variations are essentially created by the diurnal thermal tide above the clouds, and by photolysis above 80 km.

A novel approach to mineral carbonation using deep eutectic solvents for the synthesis of nano-sized amorphous CaCO3

This paper proposes a novel synthesis method for nanosized amorphous CaCO3 based on advanced mineral carbonation using the macromolecular properties of deep eutectic solvents (DESs). DESs are generally synthesized by mixing hydrogen bond acceptors (HBAs) and hydrogen bond donors (HBDs), and their properties vary depending on the HBDs and HBAs used for the synthesis. To synthesize DESs with CO2-philic properties, monoethanolamine (MEA) was selected as the HBD because it possesses a CO2-active site. However, alkanolamine-based DESs are difficult to use in practical applications because of their high viscosity following CO2 absorption. To mitigate the onset of high viscosity, H2O was added to the synthesized DESs, with the molar ratio HBA:HBD:H2O as 1:5:10 and 1:5:15. In the proposed process, CO2 was captured by the DESs-H2O system and converted into particle-size- and morphology-controlled CaCO3. Nanosized amorphous CaCO3 (ACC) with average particle sizes of 38.1 and 48.0 nm was formed by DESs based on the molar ratio of 1:5:10. The results demonstrated the need for an adequate ratio of H2O to DES to form nanosized ACC, implying that the strength of hydrogen bonding in DES-H2O systems is the primary factor affecting the performance of the solvent. The DES-H2O systems with inter- and intramolecular hydrogen bonding inhibited the crystallization of CaCO3. The findings of this study are applicable to CO2 utilization processes designed for the production of nanosized ACC.

EtOH/H2O ratio modulation on carbon for high-Voc (1.03 V) printable mesoscopic perovskite solar cells without any passivation

Based on an improved Stöber strategy, a phenol-formaldehyde resin-based carbon was developed for p-MPSCs. With optimum ratio of EtOH and H2O, the open-circuit voltage (Voc) increases from 0.97 V to 1.03 V with a maximum PCE of 17.64%.

Efficient synthesis of Co2+–Co3+ hydrotalcite-like compounds via NaOH precipitation in methanol–water under mild alkaline conditions

Divalent/trivalent cobalt hydrotalcite-like compounds (Co2+–Co3+ HTlc) were synthesized via precipitation under mild alkaline conditions by using NaOH as precipitant and methanol–water as solvent. The influences of synthetic parameters including CH3OH:H2O volume ratio, precipitation pH, and hydrothermal treatment on the HTlc formation were investigated. The crystalline phase, morphology, and chemical composition of the synthesized samples were characterized by XRD, FTIR, SEM, TG–MS, and iodometric titration. The formation of Co2+–Co3+ HTlc was strongly affected by the methanol content and a single Co2+–Co3+ HTlc phase was obtained by raising the CH3OH:H2O ratio to 4:1–8:1. It was suggested that the presence of methanol increased the concentration of dissolved oxygen and promoted the oxidation of Co2+ into Co3+, leading to complete transformation of α-Co(OH)2 into Co2+–Co3+ HTlc. Moreover, single-phased Co2+–Co3+ HTlc was available at pH between 10 and 12, and they were hydrothermally stable by treatment at 60 °C for 24 h. Under the synthetic conditions, complete precipitation of cobalt ions was achieved. This highlights that the developed synthesis process is an efficiency way for quantitative synthesis of cobalt HTlc.

Ultra-high resolution near-infrared spectrum by wavelet packet transform revealing the hydrogen bond interactions

Resolution is always an obstacle to analyzing the fine structure of a spectrum. The problem is particularly serious in the analysis of the near-infrared (NIR) spectra of aqueous solutions, because the spectrum is generally composed of overlapping broad peaks making the understanding of the structures and the interactions notoriously difficult. In this work, wavelet packet transform (WPT) was adopted to enhance the resolution of the NIR spectra of aqueous mixtures. Due to the microscopic ability of WPT in both position and frequency, the fine details of a spectrum can be observed in the spectral components of different frequencies obtained by WPT decomposition. Ultra-high resolution spectrum can be obtained from the high-frequency component representing the spectral features. Spectral features of different hydrogen-bonded OH, as well as the OH in HOH and HOD, were identified from the high-resolution NIR spectra of water and heavy water mixtures and validated by the variation of the spectral intensity with the mole ratio of H2O and D2O. The high-resolution spectrum was further applied in analyzing the interaction of amine and water. The spectral features of the hydrogen bonding between CH/NH in tert-butylamine (TBA) and OH in water were observed. The structures of CH bonded to one water molecule, and the structures of NH connecting with one and two water molecules were identified.

The parallel pathways of hydrogen oxidation reaction on high active decorated Ni–YSZ electrode in electrochemical cell with GDC protective layer

In this study, we considered the electrochemical behavior of a symmetrical electrochemical cell with a highly conductive supporting La0.88Sr0.12Ga0.82Mg0.18O2.85 electrolyte, a protective Ce0.82Gd0.18O2–δ layer and highly active Ni + Zr0.84Y0.16O1.92 electrodes in H2 + H2O + Ar gas mixtures at constant partial pressure of H2, H2O and constant ratio pH2/pH2O. It is shown that the presence of a protective Ce0.82Gd0.18O2–δ layer makes it possible to significantly increase the electrode activity by about 7 times at 800 °C and about 24 times at 700 °C. After the introduction of highly dispersed particles of cerium oxide into the electrode by the method of solution impregnation, the polarization resistance of electrode was about 0.03 Ω cm2 at 800 °C. It is shown that in the case of decorated electrodes, the mechanism of hydrogen oxidation includes two parallel pathways. One is similar to the hydrogen oxidation route for conventional nickel–ceramic electrodes, and the second includes slow stages of oxygen ions transport both in ceria particles and in the protective Ce0.82Gd0.18O2–δ layer. It is shown for the first time that with an increase in oxygen partial pressure the ratio of the rates of these pathways changes.

Nature of support plays vital roles in H2O promoted CO oxidation over Pt catalysts

Pt nanoparticle catalysts supported on a series of TiO2-SiO2 composites with different molar ratios were prepared, characterized, and their CO oxidation activities were evaluated under dry and humid conditions. Among the catalysts, Pt/1Ti-3Si showed the best performance under both conditions and potentials for future industrial applications. H218O experiments were designed and the CO2 composition was calculated to quantify the promotion effect of H2O, which was highly correlated with the concentration of H2O and Ti-Si ratio. The XRD, XPS and BET results revealed that the defects on the supports inhibited phase transformation and lattice growth for anatase TiO2. These defects also led to an increase in the number of acid sites on Pt/TiO2-SiO2. The TEM, EDS mapping, and CO chemosorption results indicated that metallic Pt0 particles were formed, which was beneficial for CO oxidation during reaction. It was found that the generation of OH from H2O dissociation and the desorption of OH on TiO2 were much easier than those on SiO2, illustrating that the H2O promotion effect could be controlled by regulating the nature of support. The mechanism of H2O promotion was proposed by experimental and theoretical methods, which confirmed the carboxyl intermediate pathway rather than the formate pathway.

Probing the initial stages of iron surface corrosion: Effect of O2 and H2O on surface carbonation

Iron plays a vital role in natural processes such as water, mineral, iron, and nutrient cycles. Iron undergoes reduction-oxidation and catalytic reactions to produce various corrosion films depending on its chemical environment. Near ambient pressure X-ray photoelectron spectroscopy, polarized modulated infrared reflection absorption spectroscopy, and Auger electron spectroscopy were used to study the key reactants, from O2(g), H2O vapor, Na+ and Cl− on the initial stages of iron surface corrosion. With increasing the ratio of O2 and H2O, surface hydrocarbons were shown to oxidize into carbonates, while the Cl− was found to migrate into the interface. The effect of each individual reactant was measured separately and water was shown to have a first order rate dependence on the carbonate growth at low pressures, with little dependence for O2. Near ambient pressures, both H2O and O2 were found to increase the carbonate growth, which was estimated using the Langmuir isotherm model, yielding Gibbs energies between −9.8 to −8.5 kJ/mol. A mechanism is suggested to explain the oxidation is catalyzed by NaCl on iron surfaces and the adventitious hydrocarbons served as the source for surface carbonation. These findings have implications for understanding other surface catalytic and redox interface chemistry in complex environments.

Formation of Para-H2O by Vacuum-UV Photolysis of O2 in Solid Hydrogen: Implication for Astrochemistry.

The observation that the ortho to para ratio (OPR) of interstellar H2O is smaller than 3 is an important yet unresolved subject in astronomy. We irradiated O2 embedded in solid H2 at 3 K with vacuum-ultraviolet (VUV) light and observed IR lines associated with para-H2O (denoted as pH2O) and nonrotating H2O-(oH2)n (where oH2 denotes ortho-H2) but no lines associated with ortho-H2O (denoted as oH2O). After maintaining the matrix in darkness for ∼30 h, the amount of pH2O decreased, accompanied by an increase in H2O-(oH2)n via diffusion of oH2. After that, the continuous nuclear-spin conversion from oH2 to para-H2 (denoted as pH2) in solid H2 over time resulted in the conversion of nonrotating H2O-(oH2)n to rotating pH2O in solid pH2. The observation of the formation and conversion of pH2O in our experiment suggests a plausible route in which VUV irradiation of O2 and H2 adsorbed on grain surfaces might be responsible for the smaller OPR of interstellar H2O.

Thermal stability of synthetic high basicity calcium silicate hydrates substituted with Cr3+ ions

In this work, the formation mechanism, the thermal stability (280–1000 °C) and the surface area properties of calcium silicate hydrates substituted with Cr3+ ions under hydrothermal conditions were investigated. In this experiment, CaO, amorphous SiO2·nH2O raw materials and Cr(NO3)3·9H2O (5 or 15 g Cr3+/dm3 (accordingly, Cr:Ca:Si:H2O ratios were equal to 0.002:1.5:1:1.098 and 0.006:1.5:1:1.094)) solutions were used. Hydrothermal synthesis was performed in unstirred suspensions, in an autoclave, under saturated steam pressure (∼ 10 bar) at a temperature of 200 °C for 1 h. The thermal stability of the synthesized samples was investigated at 280, 500 and 1000 °C with a temperature increase rate of 8.33 °C/h. It was determined that Cr3+ ions changed the formation mechanism of high basicity calcium silicate hydrates and yielded different synthesized compounds: a lower amount of Cr3+ ions accelerated the reaction of the raw material and promoted the crystallization of α-C2SH and xonotlite, while a higher concentration of Cr3+ ions effected only the formation of semicrystalline type compounds (C-S-H (I) and C-S-H (II)). Calcium silicate hydrates substituted with Cr3+ ions remained stable up to 250 °C temperature because, at a higher temperature, calcium chromate started to form. Also, when the calcination temperature was equal to 1000 °C, the Cr3+ ions additive accelerated the crystallinity of calcium silicates (wollastonite and belite). The results of the SBET measurements showed that the Cr3+ ions additive positively influenced the values of the specific surface area (total of 76.17 m2/g). However, these values decreased after the samples were calcinated at a temperature of 500 °C (the value dropped to 48.02 m2/g).

Design Optimization of Highly Efficient SOEC Co-Electrolysis Processes

Introduction Research is underway to produce synthetic fuels such as hydrocarbon fuels by reacting hydrogen derived from renewable energy with carbon dioxide and other substances, and their use towards a decarbonized society is being considered.1 In this study, we focus on high-temperature co-electrolysis of CO2 and H2O using a solid oxide electrolysis cell (SOEC), which is one of the promising CO2 conversion technologies. The objective of this study is to evaluate the influence of the electrolysis process and operating conditions on the fuel synthesis process based on heat and mass balance analysis and to propose designs for a new fuel production system. Experimental A commercial chemical process simulation software Aspen Plus was used to simulate a fuel synthesis process using SOEC high-temperature co-electrolysis. In this simulation, H2O and CO2 were considered to be supplied to the SOEC for co-electrolysis, and a fuel synthesis process such as a CH4 production reactor was connected to the outlet of the SOEC to calculate the overall system efficiency. Figure 1 describes an SOEC and a fuel synthesis reactor of the SOEC high-temperature co-electrolysis process created by Aspen Plus. Results and discussion Figure 2 shows one of the simulation results calculated using the process model shown in Figure 1, where the operating temperature of the SOEC is 800 ℃ and the reaction pressure is 1 bar. Figure 2 shows the change in gas composition after the co-electrolysis process in the SOEC by varying H2O flow rate from 1 to 5 mol min-1 relative to CO2 flow rate of 1 mol min-1. As shown in Figure 2, the conversion rate of CO2 to CO increases with increasing H2O flow rate due to the reverse water-gas shift reaction, and the ratio of H2O to CO peaked at H2O/CO2=2, and then gradually decreased. Since the ratio of these gases affects the efficiency of fuel synthesis to CH4 and other downstream gases, we have studied the appropriate fuel synthesis ratio based on the simulation results. In this presentation, we report on the results of the performance evaluation of co-electrolysis and fuel synthesis process based on the obtained simulation results, by conducting electrolysis tests using SOEC cells and evaluating cell performance and downstream gas composition under different operating conditions, based on actual experimental results. Acknowledgements This work was partially supported by JSPS KAKENHI Grant Number JP21K04981. Figure 1

Sensitivity Analysis of 1,3-Butadiene Monitoring Based on Space-Based Detection in the Infrared Band

The monitoring of the Volatile Organic Compounds (VOCs) in the atmosphere is of great significance for reducing chemical pollution, warning of fires, and improving air quality. Among the VOCs, 1,3-butadiene is essential to monitor as a carcinogenic environmental pollutant. The space-based detection of 1,3-butadiene was made possible by recently development of infrared detection satellites and advances in spectroscopic techniques. In this work, based on the demand for space-based infrared detection of 1,3-butadiene, a modeling method of Earth background radiance characteristics coupled with remote sensing data and physical model is proposed, which can effectively simulate the Earth background radiance field distribution under any atmospheric conditions. Specifically, infrared spectral radiance of 1,3-butadiene was simulated from absorption cross-section data. Further, combined with the radiative transfer model and atmospheric profiles of satellite sensor data, such as temperature, pressure, and H2O and O3 mixing ratio, the atmospheric transmittance and atmospheric background radiance are simulated. Finally, infrared space-based detection of 1,3-butadiene is simulated by coupling Earth background radiance and the detectability is analyzed and discussed by using signal-to-clutter ratio (SCR). The results show that 1,3-butadiene has an absorption effect in space-based infrared detection. The detectability of the narrow band 9.8–10.0 μm and 10.9–11.1 μm is better than that of the wide band 9.0–12.0 μm, and 10.9–11.1 μm is a better detection band for 1,3-butadiene than other bands. This paper provides a method for the space-based infrared detection of 1,3-butadiene. It also provides a reference for selecting the appropriate band for the detector.

Study on Properties of Magnesium Oxychloride Cement Solidified Soil

Due to the poor performance of ordinary Portland cement (OPC) as a solidified soil road and the large pollution in the production process, environment-friendly magnesium oxychloride cement (MOC) was used as the soil curing agent to prepare the solidified soil, exploring the optimal ratio of various raw materials when MOC is used as a curing agent. Analyzing the properties of MOC solidified soil in the application of road subgrade. This paper tests compaction, mechanical properties, and durability of the MOC solidified soil, simulates the development trend of 7 days unconfined compressive strength of MOC solidified soil, and then analyzes the hydration process and strengthens the formation mechanism of MOC in solidified soil. The study found that the addition of MOC as a curing agent to the soil can effectively improve the compaction and mechanical properties of the soil. Matlab simulation found that when the MgO content is 5.5% to 6% and the ratio of raw materials MgO, MgCl2, and H2O is 2.45 : 1 : 14 to 6.3 : 1 : 14, the performance of MOC solidified soil is excellent. Fitting UCS data, it is found that MOC solidified soil has early strength characteristics. The excellent compaction and mechanical properties of MOC solidified soil are due to the formation of a small amount of phase 5 and layered Mg(OH)2 by the hydration of MOC, and the formation of amorphous gel with SiO2 in the soil. This reaction improves soil compaction and reduces internal porosity from a microscopic perspective. The strength loss rate of MOC solidified soil is higher after immersion in water at the initial stage of curing, but it is still better than that of traditional cement-based solidified soil. Poor performance after immersion in water is associated with disruption of the network-like structure. As an environment-friendly soil curing agent, MOC can be used in engineering practice with low environmental humidity.

Anisotropic assembly and fluorescence enhancement of conjugated polymer nanostructures

AbstractThe electronic properties of conjugated polymers depend sensitively on their conformation and morphology. However, control over the morphology of conjugated polymers is highly challenging. Here, we demonstrate a facile approach for assembling conjugated polymers into anisotropic nanostructures. In a water–tetrahydrofuran (H2O–THF) binary solvent, we prepared ellipsoidal nanoparticles, which can subsequently self‐assemble into triangle‐ring and rod‐like nanostructures in a stepwise manner. The transitions among these morphologies can be rationally regulated by tuning the volume ratio of H2O to THF and the polymer concentration. The nanostructures show shape‐dependent absorption from 383 to 403 nm and significant fluorescence enhancement with a quantum yield up to 70%. The oxetane groups in the polymer side chains and the presence of surfactant in the solvent are decisive for the anisotropic assembly. We further demonstrate multicolor fluorescent nanowires with good structural integrity over doping of dye molecules or other fluorescent polymers. Single nanowires were characterized by high‐order super‐resolution optical fluctuation imaging, which revealed spatial distribution of the photooxidation sites along single nanowire for easily generating hole polarons.

A MEMS modulator-based dual-channel mid-infrared laser heterodyne radiometer for simultaneous remote sensing of atmospheric CH4, H2O and N2O.

The performance of a micro-electro-mechanical system (MEMS) modulator-based dual-channel mid-infrared laser heterodyne radiometer (MIR-LHR) was demonstrated in ground-based solar occultation mode for the first time. A MEMS mirror was employed as an alternative modulator to the traditional mechanical chopper, which makes the system more stable and compact. Two inter-band cascade lasers (ICL) centered at 3.53 µm and 3.93 µm, were employed as local oscillators (LO) to probe absorption lines of methane (CH4), water vapor (H2O) and nitrous oxide (N2O). The system stability greater than 1000 s was evaluated by Allan variance. The experimental MIR-LHR spectra (acquired at Hefei, China, on February 24th 2022) of two channels were compared and were in good agreement with simulation spectra from atmospheric transmission modeling. The mixing ratio of CH4, H2O and N2O were determined to be ∼1.906 ppm, 3069 ppm and ∼338 ppb, respectively. The reported MEMS modulator-based dual-channel MIR-LHR in this manuscript has great potential to be a portable and high spectral resolution instrument for remote sensing of multi-component gases in the atmospheric column.

A Simple Method for the Analysis of Fumarolic Gases Using Response-Adjusted Sensors with a UAV

Recent developments in unmanned aerial vehicle (UAV) technology have made it possible to measure gas compositions in volcanic plumes using lightweight compact gas sensors. However, the differences in the responses of each gas sensor can be critical in estimating gas compositions based on regression scatter plots, particularly for small plumes emitted during volcanic unrest and non-eruption periods. Based on the laboratory experiments, we show that air blowers easily adjust sensor responses and improve correlation on regression scatter plots, allowing quick composition estimates without the use of mathematical applications. Applying our measurement system, lightweight compact gas sensors for H2S, SO2, CO2, and H2O, with air blowers suspended from a UAV, were used to determine the compositions of a small plume at Io-yama, Kirishima volcano, Japan. The compositions of the plume estimated by our system were reasonably consistent with those obtained by laboratory analysis of volcanic gas collected at ground level near the vent, with fluctuations in CO2 ratios and lower H2O ratios, relative to other gases, being observed. For more accurate estimations of CO2 and H2O concentrations, low humidity conditions at a distance from the fumarole are preferable for analysis of plumes diluted by ambient dry air. Our measurement system is simple, easy to set up, and useful for estimating the compositions of small passive fumarolic gas plumes during volcanic unrest and non-eruption periods, without mathematical applications.

Optimisation of Vitamin B12 Extraction from Green Edible Seaweed (Ulva lactuca) by Applying the Central Composite Design.

Vitamin B12, only found naturally in animal-based foods, is essential for brain functions and various chemical reactions in the human body. Insufficient vitamin B12 leads to vitamin B12 deficiency, common among strict vegetarians due to their limited intake of animal-based foods. Nevertheless, extensive studies have demonstrated that macroalgae, specifically the Ulva lactuca species, are rich in vitamin B12 and could be further exploited in future dietary applications. In the current study, the ideal extraction method of vitamin B12 from dried U. lactuca was developed and optimised to achieve the maximum vitamin B12 yield. The effects of several extraction parameters, including the solvent-to-solvent, methanol:water (MeOH:H2O), and solute-to-solvent ratios, and pH on the total vitamin B12 content were analysed through a two-level factorial and central composite design. The highest vitamin B12 content, particularly cyanocobalamin (CN-Cbl), was recovered through the ultrasonic-assisted extraction (UAE) of oven-dried U. lactuca at 3 g:60 mL of solute-to-solvent and 25:75% of MeOH to H2O ratios at pH 4. The extraction of CN-Cbl from oven-dried U. lactuca that employed the UAE method has elevated CN-Cbl content recovery compared to other extraction methods.

Bridging H2O and H2S homomeric clusters via H2O-H2S mixed clusters: Impact of the changing ratio of H2O and H2S moieties

PESs of H2O-H2S mixed clusters up to tetramer have been investigated to study how replacement of conventional H-bonds by sulfur-centered H-bonds systematically modulates structure and energetic. A total of two, eight, and seventyconformers were obtained for dimers, trimers, and tetramers, respectively. Six types of noncovalent interactions were found in the studied clusters;OH---O, OH---S, SH---O, and SH---S H-bonds, andO---S and S---S interactions. Dimer and trimer are boundsolely by H-bonds, while O---S and S---S interactions along with H-bonds were identified in tetramer. Binding energies and its spread, defined by energy gaps between most and least stable conformers, were found to increase with the number of H2O monomers. Cage structures become preferable overcyclicwith increasing H2S moieties and vice versa. Relative strengths of various types of H-bondsandsignificantly higher cooperativity of classical H-bonds over their sulfur centered counterparts could be potential reasons forstructural and energetic differences.

A Compact WSGG Formulation to Account for Inhomogeneity of H2O–CO2 Mixtures in Combustion Systems

Abstract An alternative weighted-sum-of-gray-gases (WSGG) model is proposed with a single set of constant pressure-based absorption coefficients that accounts for different mole fraction ratios (MRs) of H2O–CO2. The method requires no further interpolation, which in turn brings not only less uncertainty into the model but also simplifies its use. The hitemp2010 spectral database along with the line-by-line (LBL) integration is employed to generate a set of accurate total emissivities from which the WSGG coefficients are fitted. The fitting procedure employs a novel formulation to account for the MR dependence, leading to a more compact set of WSGG correlations when compared to the alternatives available in the literature. The new formulation takes advantage of the weak interdependence of temperature and molar fraction ratio in the weight factors and therefore separates their effects by two independent correlations. As oxy-fired combustion usually occurs in two distinct scenarios, dry- and wet-flue gas recirculation (FGR), the paper also proposes two other sets of coefficients intended to support the MR ranges corresponding to these specific conditions. Comparisons made against the benchmark LBL integration and other WSGG models, for one- and three-dimensional calculations, show the satisfactory level of accuracy of the proposed sets of correlations. In particular, the three-dimensional test case illustrates that the new model is also applicable to conditions observed in air–fuel combustion.