Gas Adsorption Performance Research Articles

Poly (Vinyl Alcohol) Composite Membrane with Polyamidoamine Dendrimers for Efficient Separation of CO2/H2 and CO2/N2

Although polyvinyl alcohol (PVA) membranes are commonly used for CO2 separation, there is still large development space in mechanical properties and high selectivity of the gas separation process. In this study, the gas separation performance and mechanical properties of the (PVA/Cu2+) substrate membranes were improved by introducing polyamidoamine (PAMAM). PAMAM had an important effect on the gas adsorption and separation performance of the membrane. In addition, the gas adsorption and separation properties of the PVA/Cu2+/PAMAM membrane (PPCm) were analyzed and studied when the inlet gas pressure and the species of mixed gases were variable. The results showed that the crystallinity and mechanical properties of the membrane with the PAMAM had been significantly improved. Young’s modulus of PPCm with 30% PAMAM was 132% higher than that of the PVA/Cu2+ composite membrane without PAMAM. In addition, efficient separation efficiency and high selectivity of the gas separation process were observed. The separation factors of the PPCm for CO2/H2 and CO2/N2 were about three times higher than that of the PVA/Cu2+ substrate membranes. These results suggested that the introduction of PAMAM was promising for CO2 separation and permeance.

Evaluation of Iron-Based Metal–Organic Framework Activation Temperatures in Acetylene Adsorption

One of the major issues regarding long-term human space exploration is the need for a breathable atmosphere. A major component toward achieving this goal is both the removal of exhaled carbon dioxide (CO2) and the generation or recovery of oxygen (O2). NASA's current technology only operates at about 50% efficiency due to the need to vent the methane that is produced during the CO2 reduction process. One method of improving the efficiency of this process is through plasma pyrolysis, wherein the methane is pyrolyzed to produce hydrogen and various dehydrogenated carbon byproducts. In this process, acetylene is one of the main components of this byproduct stream. Unfortunately, while the concentration of this effluent is generally high in hydrogen (>90% typically), the presence of the acetylene waste product can act as a poison for the ruthenium-alumina catalyst used in the CO2-reducing Sabatier process, requiring a removal step. Metal-organic frameworks (MOFs) represent a valuable method for removing these unsaturated hydrocarbons due to their high tunability, particularly through the incorporation of open metal sites. In this study, two common iron-based MOFs, MIL-100 and PCN-250, were studied for their ability to adsorb acetylene. A combination of gas adsorption analysis and density functional theory calculation results shows the ability of these materials to undergo a thermal-induced reduction event, which results in an improvement in gas adsorption performance. This improvement in gas performance appears to be at least partially due to the increased presence of π-backbonding toward the acetylene molecules.

Methane Adsorption Properties in Biomaterials: A Possible Route to Gas Storage and Transportation

Methane can be stored in biomaterials rapidly in hydrate form with low energy consumption. Considering the high cost of biomaterials (vegetables or fruits), agricultural wastes may be more practical. In this work, the characteristics of methane storage in two low-cost agricultural wastes, eggplant, and static water, are studied and compared. The methane adsorption rates and capacities were greatly enhanced in three biomaterials compared with that in the static water, while only corncob pith maintained relatively high gas adsorption capacity (72 v/v) and adsorption rate (~0.0300 MPa/min) in repeatable gas adsorption-desorption processes. Further investigations on the gas adsorption behavior in the corncob pith revealed that the porous structure of corncob pith generates larger specific surface areas, providing more nucleation sites for hydrate nucleation. In addition, the hydrophobic and hydrophilic performance of corncob pith components also affect the hydrate formation. The porous structure of corncob pith reduces its water activity, which decreases the stability of methane hydrate (~0.6 MPa higher at 273.15 K for equilibrium pressure than bulk phase). These results demonstrate the great gas adsorption performance and mild storage-transportation conditions of low-cost agricultural wastes and provide significant information in promoting their application in gas storage and transportation.

SO2 capture in a chemical stable Al(III) MOF: DUT-4 as an effective adsorbent to clean CH4

Biomethane (CH4) combustion, as a renewable fuel, is an excellent alternative to decrease the CO2 emissions released into the atmosphere. However, this combustion requires catalysts which are normally poising by the presence of SO2 gas. Then, an auxiliary material capable of selective capturing the contaminant SO2 is necessary. In this work, the SO2 gas adsorption performance of a high stable Al(III) MOF known as DUT-4 was studied. In addition to the high SO2 uptake, in dry and wet conditions, and a high SO2 adsorption cyclability, we have explored for the first time a promising purification of CH4 in presence of SO2, taking into account the high affinity for SO2, even at a low concentration of SO2 (a molar gas composition of 1:99 SO2:CH4).

Hydrogen Storage Performance of γ-Graphdiyne Doped Li Based on First Principles for Micro/Nano.

The rapid development of micro/nano systems promotes the progress of micro energy storage devices. As one of the most significant representatives of micro energy storage devices, micro hydrogen fuel cells were initially studied by many laboratories and companies. However, hydrogen storage problems have restricted its further commercialization. The γ-graphdiyne (γ-GDY) has broad application prospects in the fields of energy storage and gas adsorption due to its unique structure with rigid nano-network and numerous uniform pores. However, the existence of various defects in γ-GDY caused varying degrees of influence on gas adsorption performance. In this study, Lithium (Li) was added into the intrinsic γ-GDY and vacancy defect γ-GDY (γ-VGDY) to obtain the Li-GDY and Li-VGDY, respectively. The first-principles calculation method was applied and the hydrogen storage performances of them were analysed. The results indicated that the best adsorption point of intrinsic γ-GDY is H2 point, which located at the centre of a large triangular hole of an acetylene chain. With large capacity hydrogen storage, doping Li atom could improve the hydrogen adsorption property of intrinsic γ-GDY; meanwhile, vacancy defect inspires the hydrogen storage performance further of Li-VGDY. The mass hydrogen storage density for Li2H56-GDY and Li2H56-VGDY model were 13.02% and 14.66%, respectively. Moreover, the Li2H56-GDY and Li2H56-VGDY model had same volumetric storage density, with values that could achieve 5.22 × 104 kg/m3.

Influence of Metal Identity on Light-Induced Switchable Adsorption in Azobenzene-Based Metal-Organic Frameworks.

Energy-efficient capture and release of small gas molecules, particularly carbon dioxide (CO2) and methane (CH4), are of significant interest in academia and industry. Porous materials such as metal-organic frameworks (MOFs) have been extensively studied, as their ultrahigh porosities and tunability enable significant amounts of gas to be adsorbed while also allowing specific applications to be targeted. However, because of the microporous nature of MOFs, the gas adsorption performance is dominated by high uptake capacity at low pressures, limiting their application. Hence, methods involving stimuli-responsive materials, particularly light-induced switchable adsorption (LISA), offer a unique alternative to thermal methods. Here, we report the mechanism of a well-known LISA system, the azobenzene-based material PCN-250, for CO2 and CH4 adsorption. There is a noticeable difference in the LISA effect dependent on the metal cluster involved, with the most significant being PCN-250-Al, where the adsorption can change by 83.1% CH4 and 56.1% CO2 at 298 K and 1 bar and inducing volumetric storage changes of 36.2 and 33.9 cm3/cm3 at 298 K between 5 and 85 bar (CH4) and 2 and 9 bar (CO2), respectively. Using UV light in both single-crystal X-ray diffraction and gas adsorption testing, we show that upon photoirradiation, the framework undergoes a "localized heating" phenomenon comparable to an increase of 130 K for PCN-250-Fe and improves the working capacity. This process functions because of the constrained nature of the ligand, preventing the typical trans-to-cis isomerization observed in free azobenzene. In addition, we observed that the degree of localized heating is highly dependent on the metal cluster involved, with the series of isostructural PCN-250 systems showing variable performance based upon the degree of interaction between the ligand and the metal center.

Creating Optimal Pockets in a Clathrochelate-Based Metal-Organic Framework for Gas Adsorption and Separation: Experimental and Computational Studies.

The rational design and synthesis of robust metal-organic frameworks (MOFs) based on novel organic building blocks are fundamental aspects of reticular chemistry. Beyond simply fabricating new organic linkers, however, it is important to elucidate structure-property relationships at the molecular level to develop high-performing materials. In this work, we successfully targeted a highly porous and robust cage-type MOF (NU-200) with an nbo-derived fof topology through the deliberate assembly of a cyclohexane-functionalized iron(II)-clathrochelate-based meta-benzenedicarboxylate linker with a Cu2(CO2)4 secondary building unit (SBU). NU-200 exhibited an outstanding adsorption capacity of xenon and a high ideal adsorbed solution theory (IAST) predicted selectivity for a 20/80 v/v mixture of xenon (Xe)/krypton (Kr) at 298 K and 1.0 bar. Our extensive computational simulations with grand canonical Monte Carlo (GCMC) and density functional theory (DFT) on NU-200 indicated that the MOF's hierarchical bowl-shaped nanopockets surrounded by custom-designed cyclohexyl groups─instead of the conventionally believed open metal sites (OMSs)─played a crucial role in reinforcing Xe-binding affinity. The optimally sized pockets firmly trapped Xe through numerous supramolecular interactions including Xe···H, Xe···O, and Xe···π. Additionally, we validated the unique pocket confinement effect by experimentally and computationally employing the similarly sized probe, sulfur dioxide (SO2), which provided significant insights into the molecular underpinnings of the high uptake of SO2 (11.7 mmol g-1), especially at a low pressure of 0.1 bar (8.5 mmol g-1). This work therefore can facilitate the judicious design of organic building blocks, producing MOFs featuring tailor-made pockets to boost gas adsorption and separation performances.

Drying Shrinkage Reduction of Korean Loess Using Cations

The loess produced in South Korea is an eco-friendly material with high gas adsorption performance. Korean loess, however, cannot be used as a structural material because it has a very low compressive strength compared to cement. However, even if it is recommended as an interior material, its large drying shrinkage during drying disturbs wet construction. Therefore, this study aimed to develop a method to reduce the amount of water added while maintaining the consistency required for the plastering work of Korean loess. The experimental results showed that the dispersion of clay particles was improved when Na+ and K+, which are monovalent cations, were added to the loess colloid; the reverse occurred, i.e., aggregation of clay particles, when Ca2+ and Mg2+, which are divalent cations, were added. In addition, the dispersion and aggregation of clay particles affect the consistency of loess. The dispersion allows the loess paste to obtain the required consistency using less water, but the aggregation may exhibit the opposite effect. Accordingly, based on the same consistency, the specimens with less water exhibited less drying shrinkage. The drying shrinkage decreased by 9.23% for the specimen fabricated with the 0.01 M Na2SiO3 aqueous solution.

First​ Principles-Based Study Of the Influence of Pressure on the Gas Adsorption Performance of Coal

First​ Principles-Based Study Of the Influence of Pressure on the Gas Adsorption Performance of Coal

Molecular dynamics simulation to explore the impact of wax crystal on the formation of methane hydrate

The combined problem caused by wax and hydrate deposition is the key issue to be considered for the subsea multiphase (crude oil, gas, and water) flow assurance. In our study, molecular dynamics technique was performed to generate the solid state wax crystal and further study the impact of wax crystal on the formation of methane hydrate on the microscopic level. Our simulation results showed that wax crystal played a dual role in methane hydrate formation (i.e. promotion and inhibition effects), depending on its size. Small wax crystal would shorten the hydrate nucleation time from 19 ns to about 12 ns, facilitate the 51262 cage formation and increase the conversion ratio of methane and water molecules to methane hydrate by more than 1.5 times. In this process, the competitive capture of methane in gas–liquid, gas-hydrate and liquid-hydrate phases could be detected. When the size of wax crystal exceeded the critical value, the formation of hydrate would be inhibited and the nucleation time was prolonged beyond 500 ns. In this case, the competition of methane capture between wax crystal and aqueous solution would dominated the whole process. The presence of small wax crystal accelerated the hydrate nucleation and growth by facilitating the molecular migration of H2O and CH4 to a certain extent and promoting the assembly of water and methane molecules into hydrate precursors. However, a further increase in the diffusion velocity of methane and water molecules induced by the stronger gas adsorption performance of more wax would lead to the aggregation of methane molecules into large nano-bubbles, reducing the CH4 concentration in the solution far below the hydrate formation threshold value. Eventually, hydrate cages would not be formed and survival. The results in this work would contribute to a better understanding of the wax-hydrate interaction.

Constructing novel hyper-crosslinked conjugated polymers through molecular expansion for enhanced gas adsorption performance

The porous organic polymers have been considered as effective materials for gas storage and adsorption. Herein, we synthesized highly crystalline nitrogen-rich covalent triazine frameworks (CTFs) by polycondensation for preparing the novel hyper-cross-linked conjugated polymers (HCCPs) with tunable specific surface area and pore volume through coupling Friedel-Crafts reaction, in which 1,4-Bis(chloromethyl)benzene and 4,4-Bis(chloromethyl)biphenyl as the expansion molecules were pillared between the layers of CTF-HUST. This technology not only increased the specific surface area and total pore volume of CTF-HUST by 2.56 and 4.68 times, but also greatly enhanced the utilization of adsorption sites of CTF-HUST. The HCCP2–1.25 exhibited the highest surface area (1349.29 m2g−1) among these HCCPs and demonstrated excellent adsorption performance for ethyl acetate (1605.14 mg/g), ethanol (1371.49 mg/g), 1,2-Dichloroethane (1971.68 mg/g), benzene (1151.77 mg/g) and toluene (1024.28 mg/g) due to the multiple C-H…O, C-H…Cl, O-H…N and C-H…π interactions between volatile organic compounds (VOCs) and HCCPs framework. Moreover, CO2 and H2 storage capacities of the HCCP2–1.25 were 8.02 wt% and 1.54 wt%, 1.66 and 1.67 times higher than CTF-HUST, respectively. This study developed a simple and effective molecular expansion strategy to synthesize a series of novel high-surface-area porous polymers for potential applications in the environmental field.

Failure Mechanism of Gas-Bearing Coal during Outburst and a New Method for Outburst Prediction.

Coal and gas outbursts are among the most serious disasters affecting the safety of coal mines. Gas is an important factor in these types of disasters. To analyze the characteristics of the damage caused by gas to the coal body during the sudden release of the gas process, a self-developed high-pressure gas release cause coal particle ejection experiment device was used to conduct gas release experiments under different conditions. The results show that at the moment of gas release, coal particles and gas are ejected at high speed, crushing coal particles into smaller particles. With the increase in gas pressure and gas adsorption performance, the crushing effect will increase. Also, the coal ejection strength (CES) will increase nonlinearly. By analyzing the mass ratio of ejected coal particles, based on the theory of crushing work and energy, we developed a new coal particle fragmentation index, which can be fitted linearly to CES. The index is based on the f value, which makes up for the limitations of the forecasting method, and can be used more flexibly to predict the coal sample crushing situation. Moreover, the fitting parameter values can more accurately describe the coal particle crushing grade.

The promoting mechanism of doping Mn, Co, and Ce on gas adsorption property and anti-SO2 oxidation over γ-Fe2O3 (001) surface: A density functional theory study

To improve the deNOx and anti-poisoning performance of γ-Fe2O3 catalyst, the effects of three dopants Mn, Co, and Ce on gas adsorption and SO2 oxidation were investigated by a DFT method. Results show that NH3, NO, O2 can be adsorbed stably on the γ-Fe2O3 (001) surface to form coordinated NH3, nitrosyl, and adsorbed oxygen species, respectively. SO2 and H2O bind to Fe site on the catalyst surface by weak chemisorption. Doped Mn, Co, and Ce atoms simultaneously improve the gas adsorption performance of its own site and the surrounding Fe sites, especially for Ce doping. Furthermore, doping Mn contributes to the oxidation of SO2 to SO3, while doping Co and Ce restrains the formation of SO3, especially doping Ce, which is conducive to sulfur resistance of the catalyst. By comparison, the doping of Ce has more excellent deNOx and anti-poisoning property for the γ-Fe2O3 catalyst, which provides theoretical guidance for the selection of dopant in the subsequent experiments.

Tetraphenyladamantane-based microporous polyaminals for efficient adsorption of CO2, H2 and organic vapors

Herein, a new tetraphenyladamantane-cored triazine-based multiamine (TPADT) was designed and synthesized. Its bulky molecular volume, strong rigidity, and high amine functionality enable it easy to prop up the polymer backbone and form a high hypercrosslinking degree to obtain high microporosity. A series of highly microporous tetraphenyladamantane-based polyaminals (Ad-MALPs) were prepared through the catalyst-free copolymerization of TPADT and commercial aromatic aldehydes. By changing the strut length and functionality of aldehyde monomers, the resulting polymers exhibit tailored BET surface area (1541–1779 m 2 /g) and narrow ultramicropore size distribution (0.52–0.93 nm). Ad-MALP-2 with the largest microporosity possesses the highest CO 2 uptake (21.1 wt %, 273 K/1.0 bar) and CO 2 /N 2 adsorption selectivity (35.2). Interestingly, Ad-MALP-3 shows the highest H 2 uptake (2.26 wt%, 77 K/1.0 bar) due to larger total pore volume. In addition, highly microporous Ad-MALPs simultaneously contain aromatic and cycloaliphatic components, and thus show exceptionally large aromatic and cycloaliphatic organic vapor adsorption capacity under low pressure. At P/P 0 = 0.1, the benzene and cyclohexane vapor uptakes of Ad-MALPs are up to 44.8 wt% and 39.0 wt %, far exceeding that of most previously reported porous organic polymers. Considering that Ad-MALPs have outstanding gas adsorption performance, simple preparation, good stability, and cycle ability, they are expected to be promising adsorbent materials for CO 2 adsorption/separation, H 2 storage and low-concentration volatile organic vapors capture. • A new tetraphenyladamantane-cored diaminotriazine multiamine is designed and synthesized. • A series of tetraphenyladamantane-based polyaminals (Ad-MALPs) with tunable and remarkable microporosity are fabricated. • Ad-MALPs exhibit large CO 2 uptakes and good adsorption selectivities. • Ad-MALPs possess exceptionally large H 2 uptakes and low-pressure benzene, cyclohexane vapor adsorption capacity.

Metal Exchange Boosts the CO2 Selectivity of Metal Organic Frameworks Having Zn-Oxide Nodes.

A large number of metal organic frameworks (MOFs) synthesized to date have nodes with a Zn metal, and a detailed understanding of their gas separation efficiency upon metal exchange is needed to pave the way for designing the next generation of MOFs. In this work, we implemented a protocol to identify MOFs with Zn nodes out of 10,221 MOFs and classified them into two main groups. Depending on the pore properties and adsorption selectivities, two MOFs from IRMOFs and two MOFs from ZnO-MOFs were selected. The metal atom (Zn) of the selected four MOFs was exchanged with eight different metals (Cd, Co, Cr, Cu, Mn, Ni, Ti, and V), and 32 different metal-exchanged MOFs (M-MOFs) were obtained. By performing grand canonical Monte Carlo simulations, we investigated the influence of the metal type on the CO2/H2 and CO2/CH4 separation performances of these 32 M-MOFs. Physical properties of the MOFs such as the pore size and surface area, and chemical properties such as the partial charges of the atoms in the framework were investigated to understand the effect of metal exchange on the gas adsorption and separation performances of materials. Exchange of Zn with V and Cr led to a remarkable increase in the CO2 uptakes of selected MOFs and these increases were reflected on the adsorption selectivity, working capacity, and the adsorbent performance score of MOFs. The exchange of Zn with V increased the selectivity of one of the MOFs from 119 to 355 and the adsorbent performance score from 70 to 444 mol/kg, while for another MOF, exchange of Zn with Cr increased the selectivity from 161 to 921 and the adsorbent performance score from 162 to 1233 mol/kg under the condition of vacuum swing adsorption. The molecular level insights we provided to explain the improvement in the gas separation performances of M-MOFs will serve as a guide to design materials with exceptional CO2 separation performances.

Synergistic Effect of Active Sites and a Multiple-Micropore System for a Metal-Organic Framework Exhibiting High Separation of CO2/CH4 and C2H2/CH4.

Efficient gas separation and purification play a vital role in the current advanced development of industry, and the application of MOF adsorbents in this area with highly technical materials shows obvious advantages. On the basis of reticular chemistry, the 4-c lvt MOF adsorbent [CuDTTA]·3DMF·CH3CN has been constructed (CuDTTA; H2DTTA = 2,5-bis(1H-1,2,4-triazol-1-yl)terephthalic acid). CuDTTA reveals a multiple-micropore system and high-density active sites decorated on the channel surfaces, which are conducive to its extraordinary selectivity of CO2/CH4 and C2H2/CH4 (29 and 166, 1:1). In combination with an analysis of Qst values, CuDTTA possesses the synergistic effect of size sieving and abundant functional sites, significantly improving the gas adsorption and separation performance. Meanwhile, the results also reveal that functional sites have a stronger binding affinity toward C2H2 with respect to CO2. Such a conclusion renders CuDTTA to be a promising adsorbent material for industrial applications.

Preparation of Activated Carbon Doped with Graphene Oxide Porous Materials and Their High Gas Adsorption Performance.

It is still a great challenge to develop a new porous carbon adsorbent with excellent separation performance and to recover low-concentration CH4 in coal mine gas. This work provides a new idea for the study of CH4 adsorption on activated carbon (AC) composites. Composite materials with microporous structures were prepared from coconut-shell activated carbon (CAC) doped with graphene oxide (GO) by a chemical activation process in this paper. The expansion and dissociation of GO at high temperatures indirectly improve the specific surface area (SSA) of the composite. The interlayer aggregation is reduced, the activation effect is improved, and a new low-cost adsorption material is prepared. The SSA of CAC-50 is more than 3000 m2·g–1. A high SSA and a narrow pore size distribution lead to a higher total adsorption capacity of CH4. The breakthrough test also confirmed that AC/GOs had a better adsorption capacity for CH4. The separation performance of the CH4/N2 mixture is not good at room temperature, which is due to the influence of a high SSA and average pore size. As a low-cost and rich material, CAC has a wide range of application prospects. The composite is a potential material for recovering low-concentration CH4 from the coal mine, which is worthy of attention. In the future, the selectivity of AC/GOs to CH4 can be increased by loading functional groups or modification.

General synthesis of ultrahigh-surface-area porous carbons with superior yield via preferential removal of sp2-hybridized atoms

A grand challenge in the state-of-the-art porous carbons is the lack of reliable synthesis strategy for achieving ultrahigh surface areas while maintaining a high carbonization yield. Generally, the realization of the ultrahigh surface area depends on the inherent properties of the starting precursors. Meanwhile, excessive development of porosity (>3500 m2 g−1) will undoubtedly give rise to low carbonization yield (<10%), thus far restricting cost-effective applications. Here, we report a general protocol via constructing nitrogen-doped sp2-hybridized carbon atoms in the carbonaceous matter, which guides the pore-creating agents (e.g., KOH) to preferentially etch over sp2-rather than sp3-hybridized atoms, thus greatly increasing the activation reaction efficiency to simultaneously accomplish ultrahigh porosity without sacrificing carbonization yield, a critical paradox in producing carbons. A highest Brunauer-Emmett-Teller surface area (i.e., 4376 m2 g−1) with 10 wt% carbonization yield and 3829 m2 g−1 with an unparalleled yield of 35.1 wt% are achieved so far, which enables great potential in adsorptive-related applications as exemplified by their record-high gas adsorption and supercapacitve performances. Our findings reveal important insights on directed synthesis of ultrahigh-surface-area carbons and provide an impetus for their on-demand applications.

Multi-objective genetic algorithm optimization with an artificial neural network for CO2/CH4 adsorption prediction in metal–organic framework

The industry requirement of separating gas mixtures via adsorption techniques is rapidly being imposed, as the adsorption method is regarded as superior in terms of thermodynamic efficiency and cost. Gas mixture adsorption investigations with metal–organic frameworks (MOFs) have been conducted both in experimental and molecular simulations. Molecular simulation studies are faster in predicting CO2 adsorption performance but are difficult to conduct because they require detailed information on the characteristics of the MOF. Therefore, in this study, the separation factor of CO2/CH4, the gas adsorption performance, and the heat of adsorption were predicted using artificial neural networks (ANNs). MOF texture properties that contribute to the performance are the input in this simulation. Operating working pressure and temperature are also inputs in this simulation. Optimization is conducted using the multiobjective genetic algorithm method to maximize the separation factor and CO2 uptake with mild heat of adsorption. Moreover, the optimal values will be determined via the technique for order of preference by similarity to the ideal solution (TOPSIS). Interestingly, the amount of CO2 adsorption, selectivity, and heat of adsorption are in satisfactory agreement with the values that are predicted by ANN with high validity regressing (R = 0.99). The output optimum point to get maximum capacity of CO2 and selectivity with mild heat of adsorption are 9.97 mmol/g, 362.92 kJ/kg, and 11.01 respectively. These results provide a basis for the use of machine learning algorithms in conjunction with multiobjective optimizations to investigate the output performance of gas adsorption under the requirements of industrial applications.

First-principles study of pristine and Li-doped borophene as a candidate to detect and scavenge SO2 gas

In this research, the potential application of borophene as gas sensor device is explored. The first-principles theory is employed to investigate the sensing performance of pristine and Li-doped borophene for SO2 and five main atmospheric gases (including CH4, CO2, N2, CO and H2). All gases are found to be adsorbed weakly on pristine borophene, which shows weak physical interaction between the pristine borophene and gases. The gas adsorption performance of borophene is improved by the doping of Li atom. The results of adsorption energy suggest that Li-borophene exhibits high selectivity to SO2 molecule. Moreover, analyses of the charge transfer, density of states and work function also confirm the introduction of Li adatom on borophene significantly enhances the selectivity and sensitivity to SO2. In addition, desorption time of gas from pristine and Li doped borophene indicates the Li-borophene has good desorption characteristics for SO2 molecule at high temperatures. This research would be helpful for understanding the influence of Li doping on borophene and presents the potential application of Li-borophene as a SO2 gas sensor or scavenger.