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Oil-immersed power transformers generate characteristic gases after failure,Therefore, it is necessary to analyse and monitor the soluble gases in transformer oil samples. In this study, the DFT calculation method was used to study the adsorption properties of H2, CO, C2H2, and C2H4 gases in oil on both intrinsic MoTe2 and Rh-doped MoTe2 films. In order to analyse the adsorption characteristics, this paper first obtains the most stable Rh-doped MoTe2 monolayer model through the modelling and computational analysis of different doping sites, then, the adsorption of these gases on the material surface is studied by analysing adsorption energy, charge transfer, total state density, parting density, energy band structure, differential charge density map, molecular front orbital and desorption time, and finally concludes that Rh-MoTe2 monolayer film is the ideal material for hydrogen sensing elements, due to the extremely long desorption time of CO gas, indicating that CO gas is hard to desorption on the surface of adsorbent,which shows that this process has played a certain role in promoting CO removal. Highlights Study focused on gas adsorption using DFT: Rh-MoTe2 ideal for hydrogen sensing and effective for CO removal, intrinsic MoTe2 ineffective and required metal doping. Rh doping enhanced conductivity and gas adsorption capacity in MoTe2. Rh-MoTe2 was suitable for detecting H2, C2H2, and C2H4 gases. Desorption times vary with temperature, with CO removal particularly effective at higher temperatures. Findings suggest potential applications for Rh-MoTe2 in gas sensing and removal. [ABSTRACT FROM AUTHOR]

Microporous organic polymers (MOPs) are a new type of porous materials, which have advantages of synthetic diversity, chemical and physical stability, microporous size controllability, etc. MOPs indicate broad applications in various fields such as heterogeneous catalysis, gas adsorption, separation, and storage. In recent years, MOPs have attracted an enormous attention in greenhouse gas capture due to their great potential in physisorptive gas storage. Carbazole and its derivatives have been studied extensively as Metal-Organic Polyhedra (MOPs) building blocks due to their unique structural features and versatile functionalization possibilities. This paper systematically reviews the synthesis, characterization and application of carbazole-based polymers, and relationship of structures and properties of these polymers. The application of the polymers in carbon dioxide (CO2) capture field is analysed taking advantage of their adjustable microporous structure and electron rich properties. This review also provides novel insights regarding functional polymer materials that have high ability of greenhouse gas capture and absorbing selectivity will be obtained by reasonable molecular design and efficient synthesis. [ABSTRACT FROM AUTHOR]

The paper demonstrates the prospects of using an approach for calculating adsorption isotherms of gases on micropore industrial zeolites based on the example of H2, CO2, CO, CH4, N2 adsorption on 13X and 5A zeolites using the Dubinin–Radushkevich–Astakhov (DRA) equation. Experimental adsorption isotherms of H2, CO2, CO, CH4, N2 gases on 13X and 5A zeolites of various manufacturers have been obtained, as well as ranges of the limiting adsorption volume and characteristic adsorption energy have been established. It made it possible to correctly calculate isotherms using the DRA equation in the temperature range 293–323 K and pressure range 0–30 atm. The paper proposes and solves the optimization problem of determining affinity coefficients, which allows the calculation of gas adsorption isotherms on zeolites using only one experimental isotherm of standard gas N2. The mismatch between the experimental isotherms and those calculated by the DRA equation is 14.69% for H2 (maximum) and 1.81% for CO2 (minimum). This approach makes it possible to significantly reduce the number of necessary expensive experiments in comparison with the traditional approach (using the Langmuir equations or equations derived from it), at the same time providing acceptable accuracy for practice. [ABSTRACT FROM AUTHOR]

InN monolayer with graphene-like morphology and desirable electronic property is a promising candidate for gas sensing application. In this paper, we study the adsorption and sensing performances of the Rh-decorated InN (Rh–InN) monolayer upon two typical dissolved gases in the transformers oil, namely H2 and C2H2, to explore its potential to evaluate the working condition of the transformers. Rh atom conducts n-doping on the pristine InN surface with Eb of −2.01 eV. Also, chemisorption is determined for H2 and C2H2 adsorption on the Rh–InN surface given that the Ead of −0.88 and −2.15 eV, respectively. The opposite changing trend of Eg in H2 and C2H2 systems manifests the resistance-based sensing mechanism for selective detection of two gas species. The applied electric field supports the work function analysis that an Rh–InN monolayer possesses a strong potential for field-effect transistor sensor application in terms of H2 and C2H2 detection, wherein the charge-transfer in the gas systems is tunable by altering the voltage. Moreover, the excessive electric field is not considered to be suggestible since it can impact the geometric stability of the Rh–InN monolayer. This theoretical work is meaningful to exploit novel sensing 2D materials to guarantee the good operation of the power system. Highlights Rh-decorating behaviors upon InN monolayer is studied. Expound the potential of Rh-InN monolayer for dissolved gas analysis in transformers. Analyze the effect of applied electric field on gas adsorptions. [ABSTRACT FROM AUTHOR]

Iron-based catalysts can be used as de-NOx catalysts due to their good adsorption performance to gas molecules. However, the adsorption behaviours of NH3, NO, and O2 molecules on ferrous oxide surface are unclear. In this paper, the adsorption properties of NH3, NO, and O2 molecules over FeO (100) surface and oxygen-defected FeO (100) surface were studied by a density functional theory calculation. The Fe-top of the FeO (100) surface is the most active site. NH3 and NO can be adsorbed on the Fe-top sites by N terminal. The adsorption of O2 on the Hollow site of the FeO (100) surface has a larger adsorption energy. When oxygen-defected presents on the FeO (100) surface, the adsorption performances of NH3 and NO on the Fe-top sites are slightly decreased. NO and O2 can be adsorbed on the O-defected site, in which the adsorption energy of O2 is larger. For the adsorption of double molecules, O2 + NH3 or O2 + NO adsorbed on the FeO (100) surface have synergistic effects, respectively, which enhance the adsorption performance. Moreover, the co-adsorption behaviours of O2 + NH3 and O2 + NO on the O-defected FeO (100) surface also occur. [ABSTRACT FROM AUTHOR]

The Soochow University Beamline, located at the National Synchrotron Radiation Laboratory in China, is a Soft X-ray beamline designed for studying energy-related materials and devices. It operates in the energy range of 45 eV–1100 eV and is specifically tailored for investigating Li, B, C, N, O, F K-edges, and most L-edges of transition metals. The beamline offers various capabilities, including X-ray absorption, photon in photon out, and in situ/operando studies of energy materials and devices in gas/liquid environments. It has been successful in producing high-quality research papers and is open to users worldwide. The beamline is a collaborative effort between Soochow University and the National Synchrotron Radiation Laboratory, with funding from Soochow University. It is the first synchrotron radiation beamline in China to be funded by a university. [Extracted from the article]

The zoning of the coal seam gas is zonal, which has a significant impact on the prominent prediction indicators, resulting in different prediction results for the same prominent prediction indicators in the same coal seam soft and hard coal. In this paper, the hard coal and soft coal in the coal seam are highlighted. The adsorption and desorption rules of the soft coal and hard coal in the outburst coal seam and its influence on the sensitivity of the outstanding prediction index are studied. The results show that: (1) the initial desorption of soft coal is larger than that of hard coal; (2) the outstanding prediction index has an exponential function relationship with gas pressure; (3) the sensitivity of prediction indicators is different. And concluded that: (1) the initial desorption rate of soft coal is faster than that of hard coal; (2) the outburst prediction index K1 and Δh2 increase with the increase of gas adsorption equilibrium pressure; (3) outburst prediction index K1 is more reliable than Δh2. [ABSTRACT FROM AUTHOR]

In this paper, we present a brief review of what has been learned about the adsorption characteristics of various organic molecules at the surface of ice, from more than 15 years of computer simulation studies at the molecular scale. In particular, grand canonical Monte Carlo and molecular dynamics calculations were performed to determine the adsorption isotherms, the saturation coverage of the first molecular layer at the ice surface, the preferred orientations of the molecules in their adsorption sites, and the corresponding adsorption energies. The results of the simulations indicated that the main driving force for trace gas adsorption on ice is hydrogen bonding not only between the adsorbate and the water molecules of the ice surface, but also within the adsorbate. When possible, the comparison with available experimental data showed a close agreement, supporting thus the methodology used in the modelling. Finally, the present review demonstrates how computer simulation can nicely complement experimental approaches for studying interactions between trace gases and ice under tropospheric and interstellar condition [ABSTRACT FROM AUTHOR]

Molecular simulation was used to study methane adsorption and its effect on kaolinite swelling. The effects of temperature and pressure were also analysed. The comparisons which validate the force field and model in our paper were made between simulation and experiment. Simulation results demonstrate that adsorption behaviour of methane exhibit Langmuir adsorption behaviour. The temperature has a negative effect on gas adsorption, the adsorption amounts will decrease with increasing temperature at a given pressure. A quantitative relationship between the methane adsorption and the kaolinite swelling was provided. The kaolinite-methane interaction dominates and the methane-methane interaction contributes less than 20% to the total interaction energy. The first peak in the RDFs increases with the increasing pressure, illustrating that the system becomes less structured at higher pressure. Compared with the higher temperature, the first peaks at lower temperature increase as a higher amount of methane adsorbed indicating that the interaction between the kaolinite and methane increase with decreasing temperature. Methane is strongly adsorbed on the sites of the hydrogen and oxygen atoms in kaolinite molecules. [ABSTRACT FROM AUTHOR]

Gas is one of the most important factors which causes coal and gas outburst and can influence the mechanical characteristics of coal. Coal itself is a kind of elastic carbonaceous material which can swell and shrink under the influence of gas adsorption and desorption. Solid deformations influence the porosity of coal which also changes its adsorption and desorption capability. Gas pressure due to gas adsorption in porous materials is the cause of elastic deformation of coal, which can be assessed by direct experimental measurements. In this paper, briquette coal samples are made with different sizes of coal particles and the deformations are tested during the process of gas adsorption and desorption in samples under different gas pressures. The results show that coal swells during gas adsorption and shrinks during desorption. Deformation of different coal samples under different gas pressures is variable. It is further observed that deformation of coal is proportional to gas pressure and particle size. Also, deformation is not recoverable and residual deformation develops. The relationship between residual deformation and gas pressure is derived. This study helps to reveal the damage mechanism of pore gas in cola mass. [ABSTRACT FROM PUBLISHER]

In this paper, we report a comprehensive analysis of the adsorption of argon in cylindrical pores of finite length having different dimensions and adsorbent energies. We determine the mechanisms of adsorption and desorption in the hysteresis region, and use the recently introduced mid-density scheme, as an approximate method, to determine the equilibrium transition, which is found to lie wholly within the loop and closer to the desorption branch. For a given loading in the hysteresis region, we determine the microscopic behaviour of two metastable states (one on the adsorption branch and the other on the desorption branch) and the stable equilibrium state. The adsorption metastable state is characterised by a bulging adsorbed layer, while the desorption metastable state is characterised by a liquid bridge with a meniscus at each end in the shape of a long elliptical cone. The equilibrium state has a configuration that displays a liquid bridge with hemispherically shaped menisci having areas less than those of the two menisci in the desorption metastable state. [ABSTRACT FROM AUTHOR]

Theoretical description of single gas and gas mixture adsorption equilibria can be achieved in many different ways depending on the kind of approach (microscopic or macroscopic). In this paper, we present a statistical thermodynamics approach for the calculation of mixed gas adsorption equilibrium data on uniform surfaces. The non-ideality of both the mixed gas phase and the adsorbed phase is considered by using the Redlich–Kwong EOS associated to the classic Lorentz–Berthelot mixing rules. This is an interesting way to extend the model presented in Part I and to predict multicomponent gas adsorption equilibria for highly non-ideal systems from parameters deduced from pure gas data. We present mixture adsorption isotherms and selectivity curves calculated using our model. [ABSTRACT FROM AUTHOR]

Theoretical description of single gas and gas mixture adsorption equilibria can be achieved in many different ways depending on the kind of approach (microscopic or macroscopic) and on the physical assumptions related to the nature of the adsorbent–adsorbate systems studied as well as temperature and pressure conditions. In this paper, a detailed statistical thermodynamics development is presented. It leads to a generalized expression of adsorption isotherms for pure gases on homogeneous surfaces. The non-ideality of both gas and adsorbed phases are taken into account using the Redlich–Kwong equations of state (EOS) which is adapted for two-dimension phases. Such an approach leads to a symmetrical treatment of both phases resulting in similar expressions of their EOS and of their fugacity coefficients. It allows an easy extension to gas mixtures adsorption equilibria. We present adsorption isotherms calculated using our model, the influence of the non-idealities are presented and discussed. [ABSTRACT FROM AUTHOR]