Adsorption Of Toxic Gas Research Articles

Chemical Safety Assessment of Pitch-Based Activated Carbon Pellets via Highly Toxic Gas Adsorption Properties

This study focuses on the preparation of activated carbon using a petroleum-residue-based pitch, as well as the HCl gas adsorption properties of the resulting activated carbon pellets relative to their specific surface area and pore structure. Activated carbon was prepared under various oxidation and chemical activation conditions using pitch with a softening point of 220 °C. The activated carbon was mixed with distilled water, an acrylic binder, and carboxymethyl cellulose in a specific ratio to form pellets. These pellets were then dried in an oven at 80 °C. Scanning electron microscopy, energy-dispersive X-ray spectroscopy, and Brunauer–Emmett–Teller analyses were performed to evaluate the surface structure and specific surface area of the finalized pellets. HCl gas was adsorbed at a concentration of 50 ppm while examining the adsorption characteristics relative to the pore structure and specific surface area.

Monolayer Penta-BeAs2: A Promising 2D Materials for Toxic Gas Sensor with High Selectivity.

The discovery of novel materials with high gas sensing selectivity is a key driver of gas sensor technology. Based on the recently reported two-dimensional (2D) pentagonal BeP2, we introduce penta-BeAs2 as a new member of the pentagonal family of materials for toxic gas sensors based on density functional theory (DFT). For electronic applications, a band structure calculation showed that penta-BeAs2 has indirect band gaps of 0.38 and 0.79 eV, using GGA-PBE or HSE functionals. Stability analysis confirmed that penta-BeAs2 is dynamically, mechanically, and thermally stable. The adsorption of toxic gases (CO, NO, and NO2) and nontoxic gases (H2, N2, H2O, and CO2) on the penta-BeAs2 monolayer was studied. The contrasting adsorption behavior observed between toxic and nontoxic gases on penta-BeAs2 (physisorption vs chemisorption) underscores its high selectivity for toxic gas-sensing applications. Adsorption energies for toxic gases fall within a moderate range (0.4-0.8 eV), indicating good reversibility and short recovery times at room temperature. Additionally, the quantum transport properties of penta-BeAs2 were studied using the nonequilibrium Green's function (NEGF) approach, confirming strong sensitivity and selectivity toward toxic gases.

High Performance of the Metal Organic Framework CPO‐27 for Toxic Gas Capture (NO2)

AbstractMetal‐organic frameworks of the CPO‐27 (MOF‐74) series are known for their high adsorption capacities for nitrogen oxides. On the other hand, significantly varying and partly contradictory results were reported regarding their stability to moisture. This aspect has hampered the use of these MOFs in air filtration applications. Here, we show that the stability of CPO‐27 materials towards moisture and CO2 crucially depends on the synthesis parameters. By precisely adjusting the synthetic parameter‐property relationship, it is possible to prepare a highly stable CPO‐27(Ni) MOF by a simple precipitation in water. To demonstrate the capacity for NO2, breakthrough experiments were performed under dry and wet conditions (55% relative humidity). Extremely high values of nearly 0.74 g/g in dry conditions and 1.23 g/g under wet conditions were achieved. These results pave the way for the toxicologically safe and cost‐effective preparation of a moisture‐stable CPO‐27(Ni), bridging the gap to a potential industrial application of the material for the selective adsorption of toxic gases, such as NO2.

Development of a Multiparticulate Metal-Organic Framework/Textile Fiber Swatch.

The versatility of metal-organic frameworks (MOFs) has led to groundbreaking applications in a wide variety of fields, especially in the areas of energy, environment, and sustainability. For example, MOFs can be designed for high uptake of toxic gases and pollutants, such as CO2, NH3, and SO2, but designing a single MOF that shows tangible uptake for all of these gases is challenging due to the differences in the chemical and physical properties of these molecules. To this end, integrating multiple MOFs onto textile fibers and crafting various structures have emerged as pivotal developments, enhancing framework durability and usability. MOF composites prepared on readily available textile fibers offer the flexibility essential for critical applications, including heterogeneous catalysis, chemical sensing, toxic gas adsorption, and drug delivery, while preserving the unique characteristics of MOFs. This study introduces a scalable and adaptable method for seamlessly embedding multiple high-performing MOFs onto a single textile fiber using a dip-coating method. We explored the uptake capacity of these multi-MOF composites for CO2, NH3, and SO2 and observed a performance similar to that of traditional powdered materials. Along with harmful gas adsorption, we also have evaluated the permeation and reactivity of these MOF/textile composites toward chemical warfare agents (CWAs) like GD (soman), HD (mustard gas), and VX. In combination, these results demonstrate a fundamental advancement toward establishing a consistent strategy for the hydrolysis of nerve agents in real-world scenarios. This approach can substantially increase the protection toward CWAs and enhance the effectiveness of protective equipment such as fabrics for protective garments. This dip-coating method for the integration of multiple MOFs on a single textile fiber unlocks a wealth of possibilities and paves the way for future innovations in the deployment of MOF-based composites.

First-principles study of the monolayer SnSSe for gas sensing applications

Based on first-principles calculation, we investigated the properties of toxic gases (CO, H2S, NH3, NO2, SO2) adsorption on different sides of monolayer SnSSe. Results show that all the toxic gas molecules tend to adsorb on the hollow sites above Sn. The adsorption energies of all the gas molecules are negative, ranging from −0.1026 eV to −0.2494 eV, suggesting that the adsorption of the gases is spontaneous. We also calculated the charge transfer between the gas molecules and the SnSSe. The results showed that all the gas molecules were charge donors except NO2. The recovery time of the adsorption of toxic gases on the monolayer SnSSe are also discussed through the transition state theory, and the results showed that the adsorption times of these gas molecules were below the millisecond level. Calculations of electronic properties show that the adsorption of NO2, NH3 changes the electronic structure of SnSSe near the Fermi level, while the remaining gases have little effect on the electronic structure of monolayer SnSSe near the Fermi energy level, demonstrates the potential of monolayer SnSSe for N-based gas detection. Our study is expected to provide theoretical guidance for the fabrication of SnSSe-based gas-sensitive sensor devices and performance improvement.

First principles study on toxic gas adsorption of PtSe2/GaN heterostructure modified by Cu-group elements

Monitoring and identifying toxic gases is essential due to their detrimental effects on human health and the environment. Consequently, developing high-efficiency sensors for the detection of these harmful gases is of paramount importance. Herein, we present a theoretical study on the adsorption and sensing properties of toxic gases CO, NO and NO2 on intrinsic and Cu, Ag and Au atom-decorated PtSe2/GaN van der Waals (vdW) heterostructures, based on first principles calculation investigations. The adsorption energy, charge transfer, band structures, density of states, charge density difference, electron localization functions and recovery time are analyzed. The findings reveal that the intrinsic system demonstrates weak adsorption capabilities. However, when the surface is modified with elements from the Cu-group, there is a significant improvement in the behavior related to gas adsorption. Particularly, the Ag-decorated system demonstrates optimal gas adsorption performance. Incorporating Ag atoms notably enhances the adsorption energy and the quantity of charge transfer for CO, NO and NO2, thereby promoting a shift from physical to chemical adsorption. This alteration significantly boosts the efficiency of adsorption processes for these gases. As for the recovery time, the decorated systems indicate potential application in gas detection devices and gas adsorbers at various temperatures.

Adsorption of toxic gases by Janus MoSeTe monolayers doped with transition metals and surface defects: A first-principles study

In recent years, two-dimensional TMDs materials have been proved to be high-performance gas sensor materials. Janus material is a member of the TMD family, and its gas sensing performance research is particularly important. Gas sensing mechanism of toxic gases on transition metal dichalcogenides based Janus MoSeTe monolayers is investigated using the density functional theory. Six transition metals are considered to modify the MoSeTe surface, by comparing the adsorption energies of the transition metal on both sides of the MoSeTe monolayer, it is found that the transition metal doping is more stable on the Se side. The MoSeTe surface is activated by transition metal modification, and the gas behavior is improved by transition metal modification, it is found that Ir-MoSeTe had the best sensing performance for NO2, Os-MoSeTe had the best sensing performance for CO, and Ru-MoSeTe had the best sensing performance for H2S, NO, and SO2. After that, we explain the adsorption mechanism of gas molecules by calculating the band structure, state density, differential charge density and work function of the adsorption structure, and the recovery time explain the reuse performance of the sensor. The results show that transition metal doped MoSeTe is a promising toxic gas sensor, which provides a theoretical basis for the development of new gas sensors.

A first-principles investigation of BF3 and ClF3 gas sensing on N-defected AlN nanosheets

We conducted theoretical calculations to examine the energetic stability of pristine aluminum nitride (AlN) and N-defected AlN nanosheets, along with their structural, electronic, and optical properties, utilizing density functional theory. Furthermore, we explored the adsorption properties of BF3 and ClF3 toxic gases on both pristine AlN and N-defected AlN nanosheets. Our findings reveal that the N-defect on the AlN nanosheet enhances the gas adsorption energies (−1.354 and −13.263 eV) compared to the pristine AlN nanosheet. Additionally, the absolute value of the bandgap for the N-defected AlN nanosheet increases to 3.032 eV, exceeding the 2.997 eV value of the pristine AlN nanosheet. The gas molecules suffer significant deformation due to their interaction with adsorbents. Upon BF3 gas adsorption, the bandgap of the N-defected AlN nanosheet diminishes to zero. Moreover, the recovery time after gas adsorption on the N-defected AlN nanosheet surpasses that of the pristine AlN nanosheet. Both adsorbents showed a high absorption coefficient of over 104 cm−1 in the UV region. Significant peak shifting in the optical spectra of the N-defected AlN nanosheet was observed due to gas adsorption. The pronounced changes in structural, electronic, and optical properties following toxic gas adsorption suggest that N-defected AlN nanosheets are suitable for the adsorption (dissociation) of BF3 (ClF3) gases.

Transition metals doped Zr2CF2 as promising sensor and adsorbent for NH3

The effective adsorption and treatment of toxic gases have attracted great attention amongst researchers, particularly the use of new two-dimensional materials for achieving the adsorption of toxic gases. We applied the density functional theory to investigate the stability, geometric structural, electrical, and magnetic properties of NH3 molecules adsorbed on pristine, F-vacancy defected, and transition-metals (V, Cr, Mn, Y, Nb, and Mo) doped Zr2CF2. The charge transfer and adsorption energy of the original substrate were low, indicating that the interaction between NH3 and Zr2CF2 was primarily physical adsorption. After introducing F-vacancy and TM-doping, the adsorption stability was enhanced, with the large charge transfer and high adsorption energies indicating that the adsorption of NH3 transitioned to chemisorption. Electronic density of state diagrams suggested that the enhanced interaction was mainly caused by the hybridization of the d orbitals of dopants and p orbitals of the adsorbed NH3 molecules. The adsorption energy of NH3 molecules on Y-doped Zr2CF2 was the highest at a value of −1.425eV, and the material was also explored as an adsorbent for NH3 gas. After adsorbing six NH3 molecules, the Y-doped substrate had an average adsorption energy of −1.350eV and still maintained a good thermal stability at a temperature of 300 K. These results can provide insights into the development of sensors and adsorbents based on MXenes.

Understanding sensing mechanism of N-doped graphene-based toxic gas sensors using electronic, thermal, mechanical, electrical, and sensing properties:A DFT study

A facile and feasible protocol for the evolution of sensing characteristics of three dissimilar nitrogen-doped graphene (N-G)-based ethanol, methanol, and nitrogen-oxide gas sensors using first-principle calculations. Simulated X-ray diffraction (XRD) investigation demonstrates the sharp peak located at 7.9, 11, 13.8, and 15.4° represents (100), (111), (026), and (012) facets. Electronic properties calculations predict that toxic gas adsorption reduces the charge carrier concentration and induces internal resistance. Thermal properties analyses suggest that the nature of adsorption depends on changes in Gibbs free energy. Charge density and distribution analysis disclose that the adsorption of toxic gases leads to charge transfer between toxic gases and N-G. Mechanical properties analyses predict the mechanical superiority. The N-G's electrical conductivity and resistivity of are 49.95 × 103 Ω/m, and 2 × 10−5 Ω-m respectively. The electrical properties demonstrate that the adsorption of toxic gases would be a reason for the change in electrical conductivity and resistivity. The sensing response of N-G-M in terms of resistivity is 96.04 %. The sensing response of ethanol, NO are 17.12 %, and 5.95 %. Responses of N-G-E, N-G-M, N-G-N″-Z are 0.01, 0.06, 0.14 respectively.

The Effect of Mn Doping and Ti3+ Defects at TiO2 Surfaces in NO and SO2 Gas Capture Investigated Using Near-Ambient Pressure X-ray Photoelectron Spectroscopy

The removal of air pollutants is an important research topic in order to improve the environment. In addition, many common pollutants can affect human health to varying degrees. In this work, we investigate NO and SO2 conversion by reaction with a commonly used metal oxide catalyst, TiO2. Rutile TiO2(110) single crystals and industrial powder samples used in sunscreen are studied using near-ambient pressure X-ray photoelectron spectroscopy (NAP-XPS) as a main tool. This allows in situ monitoring of the gas conversion process. We find Ti3+ defects (oxygen vacancies) or Mn oxides/cations (MnO) at the TiO2 surfaces can improve the conversion of NO and SO2 to surface-bound species. MnO and Ti3+ defects at the surface of rutile TiO2(110) exhibit a synergistic effect on the conversion of NO and SO2 that is significantly improved by nearly an order of magnitude. The by-products are mainly in the form of NO3−, SO32−, and SO42−. We find the main oxidation products formed on the single crystals are subtly different from those on the industrial powder samples. For TiO2 nanopowders (undoped and Mndoped), the presence of Mn also shows improvement in toxic gas adsorption capacity. Overall, it is believed that the outcome obtained from NAP-XPS in this research provides useful insights for the future use of TiO2 in pollutant gas capture.

First principle analysis of toxic gas adsorption on pristine WS2 and Fe-doped WS2: Implications for gas sensing

Transition metal dichalcogenides (TMDs), such as MoS2 and WS2, are the focus of current research. TMDs are employed in many applications, including optoelectronic, solar cells, gas sensing, rechargeable batteries, and spintronic devices. In the existing work, we have explored the stability of pristine and Iron (Fe) doped WS2 and the adsorption property towards harmful gases such as NO, NO2, NH3, BCl3, and SO2 by executing the first principles calculations. To analyse the electronic properties of pristine and Iron (Fe) doped WS2, band structure, the density of states, the projected density of states, electrostatic difference density, electrostatic localisation function, binding energy and charge transfer of the systems have been calculated. To study the adsorption property of the systems, adsorption energy, adsorption distance, recovery time and work function have been evaluated. Our findings represented that Fe-doped WS2 has higher magnitude charge transfer and good conductivity than pristine WS2. Also, the adsorption analysis towards the gas molecules shows that the Fe-doped WS2 shows prominent adsorption for NO, BCl3 and SO2 compared with pristine WS2. And the physisorption nature of gas molecules is noticed through no electron localisation overlap for Fe-doped WS2 and pristine WS2 systems. Therefore, we concluded that Fe-doped WS2 is ideal for gas-sensing applications.

Adsorption and Sensing of NO2, SO2, and NH3 on a Janus MoSeTe Monolayer Decorated with Transition Metals (Fe, Co, and Ni): A First-Principles Study.

This paper reports the adsorption of toxic gases (NO2, SO2, and NH3) on a MoSeTe structure based on first principles. It was found that the gas (NO2, SO2, and NH3) adsorption on a pure MoSeTe monolayer was weak; however, the adsorption performance of these gas molecules on transition-metal-atom-supported MoSeTe monolayers (TM-MoSeTe) was better than that on pure MoSeTe monolayers. In addition, there was more charge transfer between gas molecules and TM-MoSeTe. By comparing the adsorption energy and charge transfer values, the trend of adsorption energy and charge transfer in the adsorption of NO2 and SO2 was determined to be Fe-MoSeTe > Co-MoSeTe > Ni-MoSeTe. For the adsorption of NH3, the effect trend was as follows: Co-MoSeTe > Ni-MoSeTe > Fe-MoSeTe. Finally, by comparing their response times, the better gas sensor was selected. The Ni-MoSeTe system is suitable for NO2 gas sensors, and the Fe-MoSeTe and Co-MoSeTe systems are suitable for SO2 gas sensors. The Fe-MoSeTe, Co-MoSeTe, and Ni-MoSeTe systems are all suitable for NH3 gas sensors. Janus transition-metal dichalcogenides have the potential to be used as gas-sensing and scavenging materials.

Graphene-based resistant sensor decorated with Mn, Co, Cu for nitric oxide detection: Langmuir adsorption & DFT method

PurposeThe purpose of this paper is to investigate the ability of transition metals (TMs) of iron-, nickel- and zinc-doped graphene nanosheet for adsorption of toxic gas of nitric oxide (NO). The results of this paper have provided a favorable understanding of the interaction between TM-doped graphene nanosheet and NO molecule.Design/methodology/approachA high performance of TM-doped graphene nanosheet as a gas sensor is demonstrated by modeling the material’s transport characteristics by means of the Langmuir adsorption and three-layered ONIOM/ density functional theory method. The Langmuir adsorption model has been done with a three-layered ONIOM using CAM-B3LYP functional and LANL2DZ and 6–311G (d, p) basis sets by Gaussian 16 revision C.01 program towards the formation of of NO→TM(Mn, Co, Cu)-doped on the Gr nanosheet.FindingsThe changes of charge density for Langmuir adsorption of NO on Mn-, Co- and Cu-doped graphene nanosheet orderly have been achieved as: ΔQCo-doped = +0.309 >> ΔQMn-doped = −0.074 > ΔQCu-doped = −0.051. Therefore, the number of changes of charge density have concluded a more remarkable charge transfer for Mn-doped graphene nanosheet. However, based on nuclear magnetic resonance spectroscopy, the sharp peaks around Cu doped on the surface of graphene nanosheet and C19 close to junction of N2 and Co17 have been observed. In addition, Cu-doped graphene sheet has a large effect on bond orbitals of C8–Cu 17, C15–Cu 17 and C16–Cu17 in the adsorption of NO on the Cu-doped/Gr which has shown the maximum occupancy. The amounts of through IR computations based on polarizability have exhibited that has indicated the most energy gap because of charge density transfer from the nitrogen atom in NO to Mn-doped graphene nanosheet, though Originality/valueThis research aims to explore the adsorption of hazardous pollutant gas of “NO” by using carbon nanostructure doped by “TM” of iron, nickel and zinc to evaluate the effectiveness of adsorption parameters of various TM-doped graphene nanosheets.

Trace SO2 Gas Capture in Stable 3D Viologen Ionic Porous Organic Framework Microsphere.

Eliminating trace sulfur dioxide (SO2) using nanoporous adsorbents is industrially preferred yet of great challenge due to the competitive adsorption of CO2. Herein, we reported a highly stable 3D viologen porous organic framework (Viologen-POF) microsphere via one pot polymerization reaction of 4,4'-bipyridine and tetrakis(4-(bromomethyl)phenyl)methane. Compared to the previously reported irregular POF particles, viologen-POF microsphere shows better mass transfer uniformity. Owing to the intrinsic separated positive and negative electric charges center in viologen-POF microspheres, it exhibits excellent SO2 selective capture performance, which can be collaboratively confirmed by static single-component gas adsorption, time-dependent adsorption rate, and multicomponent dynamic breakthrough experiments. Viologen-POF exhibits high SO2 absorption capacity (1.45 mmol g-1) at ultralow pressure of 0.002 bar and high SO2/CO2 selectivity of 467 at 298 K and 100 kPa (SO2/CO2, 10/90, v/v). The theoretical calculations based on density functional theory (DFT) and DMol3 modules in Material Studio (MS) were also performed to elucidate the adsorption mechanism of viologen-POF toward SO2 at the molecular level. This study represents a new type of viologen porous framework microsphere for trace SO2 capture, which will pave the way on the applications of ionic POF for toxic gas adsorption and separation.

Structural design and development of multilayered polymeric nanofibrous membrane for multifaceted air filtration/purification applications

ABSTRACT Developed a bilayered nanofibrous membrane, aimed to achieve a new class of air filtering media that can capture particulate matter, microbes and can also adsorb the harmful toxic gaseous components like formaldehyde (primary indoor pollutant). A layer of oriented nanofibers prepared via coaxial electrospinning with poly(m-phenylene isophthalamide) as core, polyacrylonitrile/polyethylenimine blended polymer as shell and another layer of randomly aligned nanofibers (polyacrylonitrile-silver nanoparticle nanofibers produced using single-nozzle electrospinning) were put together, to provide stable porous structure and induce multilevel filtration. The successful synthesis of this robust coaxial-based nanofibrous filter medium would not only make it a promising candidate for air filtration, but it will provide a new insight into designing and fabricating composite coaxial nanofiber-based membranes by incorporating various functional materials into shell for toxic gas adsorption related applications and the core can be of a mechanically robust material to address the easily collapsing cavity structure of nanofibers. The results revealed that the developed filter with superior mechanical property (11.88 MPa by virtue of poly(m-phenylene isophthalamide) fiber macromolecule that existed as rigid skeletal structure) can provide high removal efficiencies of 99.23% toward particulate matter, 99.6% toward bacterial aerosols, adsorb formaldehyde an indoor toxic gaseous pollutant and have potential antimicrobial effects against Escherichia coli and Bacillus subtilis while maintaining low pressure drop of 53.03 MPa, which to the best of our knowledge, has never been accomplished with a single filter medium before.

Adsorption of toxic gases by metal-organic frameworks


 
 
 
 Along with global economic development and population growth, the discharge of highly toxic and corrosive anthropogenic byproducts into the atmosphere or aquatic habitats creates a serious threat to human health. In order to remove such byproducts, more attention should be paid to innovative materials with high uptake capacity and performance. Metal-organic frameworks (MOFs) are crystalline, porous, hybrid materials that are made up of organic ligands as linkers and metal cluster-based nodes. Because of their beneficial features such as their large surface area, tailorable pore sizes, structural diversity, catalytic activity, and wide range of chemical and physical properties, MOFs offer significant potential as adsorbents. As a result, these materials have drawn a significant amount of attention for the capture and/or detoxification of hazardous and toxic chemicals. This review will focus on recent advancements on MOF based experimental and computational studies related to the capture of toxic gases including hydrogen sulfide (H2S), ammonia (NH3) sulfur dioxide (SO2) carbon monoxide (CO), and nitrogen oxides (NOx).
 
 
 

Fabrication of Rigid Isocyanate-Based Polyimide Foam Achieved Excellent Use Safety via Synergy between Expandable Graphite and Phosphorus-Containing Polyol

For the advantages of low cost, excellent thermal insulation, and sound absorption properties, the rigid isocyanate-based polyimide foam (RPIF) presents great application prospects as a building insulation material. However, its inflammability and the accompanying toxic fumes create huge safety hazard. In this paper, reactive phosphate-containing polyol (PPCP) is synthesized and employed with expandable graphite (EG) to obtain RPIF with excellent use safety. EG can be considered as an ideal partner for PPCP to weaken the drawbacks in toxic fume release. Limiting oxygen index (LOI), cone calorimeter test (CCT), and toxic gas results show that the combination of PPCP and EG can synergistically enhance flame retardancy and the use safety of RPIF owing to the unique structure of a dense char layer possessing a flame barrier and toxic gas adsorption effects. When EG and PPCP are simultaneously applied to the RPIF system, the higher EG dosage will bring higher positive synergistic effects in the use safety of RPIF. The most preferred ratio of EG and PPCP is 2:1 (RPIF-10-5) in this study; RPIF-10-5 shows the highest LOI, low CCT results and specific optical density of smoke, and low HCN concentration. This design and the findings are of great significance to improving the application of RPIF.

In Situ Synthesis of Hierarchical Porous Zr-MOFs on Columnar Activated Carbon and Application in Toxic Gas Adsorption.

Metal organic frameworks (MOFs) have been explored as adsorption materials owing to their diversity, controllable structure, high specific surface area, and abundant active sites. However, the shaping of MOFs has become a critical issue hindering their commercial application. A binder or high pressure is commonly used in traditional powder shaping, causing pores to be blocked or collapsed and porosity to be decreased, eventually leading to the degradation of adsorption performance. In this paper, Zr-MOFs were in situ grown on a columnar activated carbon (CAC) matrix, and a series of Zr-MOFs/CAC composites were prepared. The adsorption properties for SO2 and NO2 were measured by dynamic adsorption tests, and the Wheel-Jonas model was used to calculate the saturated adsorption capacity. Abundant mesopores can be formed between MOF crystals and activated carbon particles, and the mesoporosity of Zr-MOFs/CAC composites reached over 50%. Owing to the abundant mesoporous, increased activated sites as well as the synergistic effect between MOFs and activated carbon, the as-obtained HP-Zr-MOFs/CAC exhibited the best adsorption performance both for SO2 and NO2, which are 34.2 and 17.4 mg g-1, respectively, while the adsorption capacities of CAC for SO2 and NO2 are 20.9 and 6.6 mg g-1, respectively. The outstanding performance and facile synthesis process of HP-Zr-MOFs/CAC composites could provide ideas to develop other hierarchical porous MOFs/activated carbon composites.

Theoretical Study and Application of Doped 2D PbSe for Toxic Gases

Herein, 2D doped PbSe is used to design a gas sensor to monitor the presence of SO2 and Cl2. The stability and feasibility of doped materials are studied. Based on first principles, the adsorption of toxic gases by 2D doped PbSe is verified by density of states, Bader charge, electron localization function, and differential charge density calculations. The calculation results show that Ge1Ge3 and Sn1 are suitable for adsorption of Cl2, and the bandgap decreases by roughly 69%. Ge1Ge2 and Sn1 are suitable for adsorption of SO2, and the bandgap decreases by roughly 38%. This provides the possibility of designing gas sensors for SO2 and Cl2 based on 2D doped PbSe.