Adsorption Of Molecules Research Articles

Triggering Asymmetric Layer Displacement Polarization and Redox Dual-Sites Activation by Inside-Out Anion Substitution for Efficient CO2 Photoreduction.

Sluggish bulk charge transfer and barren catalytic sites severely hinder the CO2 photoreduction process. Seeking strategies for accelerating charge dynamics and activating reduction and oxidation sites synchronously presents a huge challenge. Herein, an inside-out chlorine (Cl) ions substitution strategy on the layered polar Bi4O5Br2 is proposed for achieving layer structure-dependent polarization effect and redox dual-sites activation. Cl ions in the bulk phase shrink the halogen layer interspace by 8‰, triggering asymmetric [Bi4O5]2+ layer displacement polarization, prolonging the average photocharge lifetime to 201.8ps. Meanwhile, surface substituted Cl ions enhance the electron-donating capability of neighboring Bi atoms, activating the intrinsic Bi reduction sites, and increasing H2O molecule adsorption on nearby intrinsic O oxidation site (cal. by 0.105eV), also self-donating as an alien oxidation site. Besides, Cl upshifts the p-band center closer to the Fermi level, facilitating the reactant adsorption. Therefore, the energy barrier for CO2 activation and rate-limiting *COOH intermediate formation steps are significantly decreased. Without cocatalysts and sacrificial reagents, inside-out Cl-substituted Bi4O5Br2 delivers a remarkable CO2-to-CO photoreduction rate of 50.18µmol g-1 h-1, being one of the state-of-the-art catalysts. This finding offers insights into exploiting polarization at the molecular-level and enhances understanding of catalytic site activation.

Preparation and Performance Study of Zinc Dibenzyl Dithiocarbamate Self‐Assembled Film on Electrodeposited Cu–Ni Alloy Surface

ABSTRACTThis study developed a green and efficient surface protection method for Cu–Ni alloys. A zinc dibenzyl dithiocarbamate film was prepared on the surface of electrodeposited Cu–Ni alloys using the self‐assembly method to improve the material's corrosion resistance in seawater. The influence of zinc dibenzyl dithiocarbamate concentration and self‐assembly time on the corrosion resistance of the self‐assembled films was investigated through electrochemical testing. The findings revealed that at a zinc dibenzyl dithiocarbamate concentration of 10 mmol/L and a self‐assembly time of 20 min, the self‐assembled film exhibited the most robust corrosion resistance, achieving a maximum corrosion inhibition efficiency of 97.70%. The self‐assembly and adsorption mechanism of zinc dibenzyl dithiocarbamate were explored using molecular dynamics simulations and adsorption isotherms. The protective effect of self‐assembled films was visually observed through salt spray testing. Zinc dibenzyl dithiocarbamate self‐assembled film technology has high application prospects in the field of marine anti‐corrosion.

Reversible Tuning Electrical Properties in Ferroelectric SnS with NH3 Adsorption and Desorption.

Two-dimensional (2D) ferroelectrics usually exhibit instability or a tendency toward degradation when exposed to the ambient atmosphere, and the mechanism behind this phenomenon remains unclear. To unravel this affection mechanism, we have undertaken an investigation utilizing NH3 and two-dimensional ferroelectric SnS. Herein, the adsorption and desorption of NH3 molecules can reversibly modulate the electrical properties of SnS, encompassing I-V curves and transfer curves. The response time for NH3 adsorption is approximately 1.12 s, which is much quicker than that observed in other two-dimensional materials. KPFM characterizations indicate that air molecules' adsorption alters the surface potentials of SiO2, SnS, metal electrodes, and contacts with minimal impact on the electrode contact surface potential. Upon the adsorption of NH3 molecules or air molecules, the hole concentration within the device decreases. These findings elucidate the adsorption mechanism of NH3 molecules on SnS, potentially fostering the advancement of rapid gas sensing applications utilizing two-dimensional ferroelectrics.

Environmental Impact of Synthetic Dyes on Groundwater in Malaysia: Sources, Distribution, Transport Mechanisms, and Mitigation Strategies

Synthetic dyes, extracted from natural sources like insects, plants, coal, and ochre, have become prevalent due to their advantages over natural dyes. However, their production has led to increased environmental pollution, particularly in groundwater. Groundwater contamination from synthetic dyes occurs through advection, dispersion, and retardation. This review aims to highlight the environmental impacts of synthetic dyes on groundwater, elucidate the mechanisms of dye transport, and propose effective strategies for monitoring and mitigating contamination. Urban runoff carries dyes from surfaces such as roofs, parking lots, and roads into stormwater systems, while agricultural runoff transports dyes from products like soil conditioners, fertilizers, and seed coatings into water bodies. In groundwater, dyes move through the aquifer via advection, dispersion, and retardation, all influenced by groundwater flow and geological conditions. The advection process involves the bulk movement of groundwater carrying dissolved dyes, while dispersion causes dyes to spread and dilute over time and distance. Retardation, which involves the adsorption of dye molecules onto soil particles, slows dye movement, prolonging their presence in groundwater. Understanding the sources, distribution, and movement of synthetic dyes in groundwater is crucial for developing strategies to protect water resources and reduce environmental and health impacts. The extensive use of dyes in industrial and domestic activities necessitates comprehensive monitoring and management to ensure sustainable groundwater quality.

Paper-Based Analytical Devices Based on Amino-MOFs (MIL-125, UiO-66, and MIL-101) as Platforms towards Fluorescence Biodetection Applications

In this study, we designed three promising platforms based on metal–organic frameworks (MOFs) to develop paper-based analytical devices (PADs) for biosensing applications. PADs have become increasingly popular in field sensing in recent years due to their portability, low cost, simplicity, efficiency, fast detection capability, excellent sensitivity, and selectivity. In addition, MOFs are excellent choices for developing highly sensitive and selective sensors due their versatility for functionalizing, structural stability, and capability to adsorb and desorb specific molecules by reversible interactions. These materials also offer the possibility to modify their structure and properties, making them highly versatile and adaptable to different environments and sensing needs. In this research, we synthesized and characterized three different amino-functionalized MOFs: UiO-66-NH2 (Zr), MIL-125-NH2 (Ti), and MIL-101-NH2 (Fe). These MOFs were used to fabricate PADs capable of sensitive and portable monitoring of alkaline phosphatase (ALP) enzyme activity by laser-induced fluorescence (LIF). Overall, amino-derivated MOF platforms demonstrate significant potential for integration into biosensor PADs, offering key properties that enhance their performance and applicability in analytical chemistry and diagnostics.

Novel tempo oxidized polyvinyl alcohol/ cellulose nanocrystal-based nanocomposite membrane for malachite green dye removal.

In this study, in-situ modification by TEMPO oxidation was performed after nanocomposite synthesis to improve its properties toward dye molecule removal. The unoxidized and oxidized polymeric-based nanocomposite was denoted as PNC6 and PNC6O respectively. The nanocomposites were characterized using FESEM, FTIR, contact angle, XRD and BET analysis. Measurements of swelling ratio and chemical stability were also performed to provide insight into the durability of the nanocomposites. The effects of changing variables included contact duration, pH of aqueous solution, initial pollutant concentration, and temperature were observed. The kinetic study showed that the experimental data is best fitted with pseudo-second-order kinetics (R2 = 0.988 and 0.997 respectively), whereas on observing isotherm data, in both unoxidized and oxidized nanocomposite it fits well with Langmuir isotherm (R2 = 0.951 and 0.993 respectively). In addition, the effects on Gibb's free energy, Enthalpy, and Entropy were measured in terms of thermodynamic characteristics, it was established that dye molecules adsorption mechanism is endothermic and spontaneous in behaviour. To check regeneration tendency of the nanocomposite seven consecutive adsorption desorption cycles were run and about 90% and 80%, regeneration ability could be seen in an unoxidized state (PNC6) and an oxidized state (PNC6O) respectively upto 5th cycle after that the tendency get reduced. This study suggests that this novel polymeric nanocomposite can be employed as an efficient and relatively inexpensive adsorbent for dye removal from aqueous solutions.

Theoretically design of 2D penta-BN2/penta-Graphene wdW heterostructure for NO gas sensing implications: a first-principles study

As air pollution becomes more and more serious, the detection of harmful gas of NO has become an urgent need in daily life. In this paper, the electronic and gas-sensing properties of penta-BN2/penta-Graphene heterojunction (P-BN2/P-G) are studied by density functional theory and non-equilibrium Green's function method. The analysis results indicate that the P-BN2/P-G heterojunction has metallic properties. The electronic structures in combination with the adsorption behavior shows that the P-BN2/P-G heterojunction can chemically adsorb NO gas molecules, and there is obvious charge transfer, indicating that it has high gas sensitivity to NO gas. In addition, the sensing performance of the gas sensor constructed by NO adsorption on upper, middle and lower layers of the P-BN2/P-G heterojunction is deeply studied. Transport calculations show that when NO is adsorbed on the upper and middle layers of the P-BN2/P-G heterojunction-based gas sensor, the current of the device decreases significantly. When adsorbed on the lower layer, the current shows a trend of first decreasing and then increasing. Under a bias of 0.1 V, the gas sensitivity can reach up to 49% when NO is adsorbed in the middle layer, which is substantially higher than that of the P-BN2 monolayer device. It can be seen that the gas sensitivity is significantly improved after forming the heterojunction. In addition, the bias transport spectrum and scattering state can reveal the change in device current caused by the adsorption of NO gas molecules, thereby clarifying its microscopic mechanism. Finally, all the findings indicate that penta-based materials can be used as a very promising gas-sensitive material for detecting NO.

Nano-MnOx prepared by redox method for toluene oxidation removal from air

Catalytic oxidation is an efficient VOCs removal technology with great potential and development advantages. The key to the oxidative elimination of VOCs lies in the development and application of the catalyst with high efficiency. In this work, the nano-MnOx catalysts were prepared by redox method and the catalytic oxidation performance of toluene was studied. The calcination temperature could effectively change the surface chemical composition and the nano-MnOx catalyst structures, which could effectively regulate the number of active centers on the catalyst surface to improve the adsorption, activation, and oxidation ability of the nano-MnOx catalysts for toluene molecules. The nano-MnOx catalyst dominated by the MnO2 phase, which was prepared at the calcination temperature of 400 °C, had a high specific surface area, developed porosity, abundant reactive oxygen species, and oxygen vacancies. The structural characteristics are conducive to the adsorption, activation, and oxidation of toluene molecules, and thus exhibited excellent toluene catalytic oxidation activity. At the reaction temperature of 140 °C, the toluene oxidation conversion was as high as 99.4 %, and the toluene conversion remained above 96.6 % after experiencing a 690 min stability test.

Electrochemical, surface, and theoretical investigations of palm kernel shell extract as an effective inhibitor for carbon-steel corrosion in 1M HCl solution.

Herein, we employed palm kernel shell extract (PKSE) as an eco-friendly inhibitor for carbon steel in acidic-induced corrosion. The corrosion inhibition of PKSE on carbon steel in 1M HCI solution was investigated by electrochemical impedance spectroscopy, weight loss, and potentiodynamic polarization measurements. The surface was characterized by scanning electron microscopy equipped with energy-dispersive X-ray spectroscopy. Moreover, the elastic modulus and hardness tests were conducted. Weight loss measurements revealed that the optimum concentration of inhibitors is 500ppm with 95.3% inhibition efficiency in 1M HCl solution. Electrochemical results showed that the inhibitor could exhibit excellent corrosion inhibition performance and displayed mixed-type inhibition. The electrochemical impedance spectroscopy analysis shows that the inhibition performance increases by increasing the concentration of PKSE. The surface studies ensure the PKSE effectiveness in carbon steel surface damage reduction. Also, the adsorption of PKSE molecules on the carbon steel surface occurs according to the Langmuir isotherm model. The primary goal of this investigation was the utilization of palm kernel shell extract as corrosion inhibitor for 1018 low carbon steel in 1M HCl solution, which highlights its novelty. The present results will be helpful to uncover the versatile importance of palm kernel shell compounds in the corrosion inhibition process.

Molecular Simulation of Cyclohexane in Nanoporous Materials: Adsorption of Conformers and Coadsorption with Water and Carbon Dioxide.

Molecular simulation is used to investigate the adsorption of an organic molecule and its different conformers into various nanoporous adsorbents. In more detail, we perform grand canonical Monte Carlo simulations to determine the adsorption isotherms for cyclohexane with its three conformers (chair, boat, and twisted boat) at three different temperatures into a molecular model of active carbons and two metal-organic frameworks (MOFs) (Cu-BTC and Al-Fum). By considering the adsorption of each conformer separately, we show that the adsorption isotherms are weakly dependent on the molecular conformation. When considering the concomitant adsorption of the three conformers under realistic conditions (to verify the population of each conformer in bulk mixtures), we show that the chair conformer is predominantly adsorbed in each material. However, such favorable adsorption mostly reflects the fact that this conformer has the largest population in the bulk mixture under the same thermodynamic conditions. On the contrary, with an increase in the cyclohexane gas pressure, the adsorption of boat and twisted boat conformers increases, while that of the chair conformer decreases as packing (entropy) effects become predominant during confinement. The adsorption of cyclohexane in the active carbon and MOF materials is also considered in the presence of water and CO2 atmospheres. In the case of the Al-fumarate material, the material is found to be strongly organophilic so that water and CO2 adsorption are negligible, and cyclohexane adsorption is not affected by competitive adsorption under any considered thermodynamic condition. On the contrary, for the active carbon and Cu-BTC material, competitive adsorption between cyclohexane and water or CO2 is observed even if cyclohexane adsorption remains preferred. While the different molecules coexist in the adsorbed phase at low pressures, increasing the cyclohexane pressure beyond 103 Pa promotes cyclohexane adsorption concomitantly with water and/or CO2 desorption.

Temperature-induced evolution of CuOx clusters in CuOx/TiO2 catalyst for boosting auto-exhaust oxidation

Developing non-noble metal oxides, replacing platinum group catalysts for auto-exhaust purification, where their usage amount exceeds 40 % of global demand, remains a challenge. Herein, we presented a combined approach on the synthesis and application of robust CuOx/TiO2 catalysts with ultra-fine CuOx clusters (ca. 1 nm). The strong interaction between CuOx and TiOx induces favorable interfacial charge accumulation, facilitating the extraction of the interfacial oxygen atoms in Cu2-x-O-Ti4-y chains and the surface lattice oxygen on CuOx clusters. Isotope 18O2 experiments and DFT calculations jointly confirmed that these oxygen atoms preferentially participate in the oxidation through the Mars-van Krevelen mechanism below 250 °C. The resulted oxygen vacancies facilitate the adsorption and activation of O2 molecules, which will participate the oxidation above 250 °C through Eley-Rideal mechanism. The increase in the temperature also drives the synergy of active oxygen species in the interfacial Cu2-x-O-Ti4-y bond chains and on CuOx clusters, cooperatively promoting the conversion of NO to NO2. As a result, the CuOx/TiO2 catalyst exhibits exceptional catalytic performance in soot oxidation, with a four-fold higher reaction rate (4.17 μmol g−1 min−1) than that of single-atom Cu₁-TiO2 catalyst. Such findings provide a novel strategy for the advancement of Cu-based cluster catalysts in environmental applications.

A first-principles study of the effects of temperature on the atomic and electronic structures of Mg-montmorillonite with H2O molecule adsorption

The interaction between water and soft rock rich in clay minerals is one of the main factors causing damage in soft rock tunnel engineering. The effects of temperature on the atomic structure and water absorption capacities of clay minerals cannot be ignored. In the present study, the influence of temperature on the microstructure of Mg-montmorillonite and the thermal stability of the Mg-montmorillonite (010) surface were calculated based on density functional theory. Furthermore, the adsorption properties of H2O molecules within different coverages (0 < Θ ≤ 1.0 ML) on the (010) surface were investigated in the temperature range of 0–900 K. First, the volume of Mg-montmorillonite expanded significantly with increasing temperature along the z-axis direction. The surface energy of the Mg-montmorillonite (010) surface decreased with increasing temperature, indicating that the high temperature weakened the interatomic interactions on the surface. Moreover, the calculations demonstrated that H2O molecules could still be stably adsorbed on the Mg-montmorillonite (010) surface at different temperatures, and the order of stable adsorption configurations for a single H2O molecule was hollow > bridge > interlayer bridge > top sites. With increasing coverage of H2O molecules, the adsorption energies increased for the top sites, while decreased for the bridge, hollow, and interlayer bridge sites at high temperature. In addition, the changes in atomic structure and electronic characteristics during water absorption were further explored by calculating the ICOHP, PDOS, and lattice relaxation.

Study on the effect of spatial adsorption orientation on the preferential selection mechanism of dust suppression surfactants

Surfactants are widely used in the field of coal dust control. However, the dust suppression effect of different surfactants varies significantly, and the preferential selection mechanism of dust suppressants for mining is not clear. In this study, the water/surfactant/lignite system was constructed by molecular simulation to investigate the adsorption behavior of surfactants with different structures on the lignite surface at the molecular level. The reasons for the differences in the wettability adsorption of sodium dodecyl sulfate (SDS), sodium dodecyl benzene sulfonate (SDBS), fatty alcohol polyoxyethylene ether-9 (AEO-9), and alkyl polyglycoside (APG1214) on the lignite surface were also investigated based on the quantum chemical calculations and macroscopic experimental analysis. The results showed that the adsorption orientation of surfactant molecules at the solid–liquid interface exerted a pivotal influence on the surface wettability of lignite. According to molecular orbital and electrostatic potential analysis, surfactant molecules with LUMO distributed in the tail chain were more inclined to form a positive adsorption orientation than that concentrated in the polar headgroups; and the stronger the interaction between the polar headgroups and the coal surface with the like charge, the more stable the adsorption of surfactant molecules with the positive arrangement at the interface was. Furthermore, the stronger potential difference between SDS molecules and the hydroxyl-rich structure of the APG1214 molecules are conducive to the formation of hydrogen bonds with water molecules. Wettability experiments showed that the ability of surfactants to improve the wettability of coal dust was positively correlated with the adsorption orientation.

Temperature-Dependent Oxidation Behavior of Silicon Carbide Surface: Reactive Molecular Dynamics Simulations.

The high-temperature oxidation mechanism of silicon carbide (SiC) is crucial for designing thermal protection systems in aircraft. This study explored the oxidative chemical reaction processes and mechanism on SiC surface and interfaces within the temperature range of 300-2300 K by using reactive molecular dynamics simulation. The oxygen impact on the silica (SiOx) growth of the SiC surface was analyzed, which shows a progressive increase of silica thickness. The simulation results indicated that the oxidation process of SiC was a typical passive oxidation mechanism. With the environmental temperature rising and oxygen impact, the increase of oxidation thickness on the SiC surface undergoes three oxidizing reaction processes: little chemical adsorption of oxygen molecules on the initial surface, rapid oxidation of silicon and carbon, and dramatic oxidation of the interface between the oxidation layer and SiC. Additionally, this work studied the mechanism of oxidation thickness growth and chemical diffusion of oxygen. The oxidation rate is weakened according to the oxygen atom diffusion barrier effect of silica repulsion. Moreover, the kinetic parameters were statistically calculated by fitting the growth of Si-O bonds and their reaction rate constants. Subsequently, the activation energy and pre-exponential factors were derived by using the Arrhenius equation to model the chemical reaction kinetics of the thermal oxidation process. The chemical reaction behaviors of the two stages could be concluded as follows: (i) in stage I, the initial oxidation is reaction rate limiting; (ii) in stage II, SiC oxidation is limited by both the oxidation reaction rate and the oxygen diffusion coefficient of the oxidation layer. The activation energy of stage II increased compared with stage I due to the oxygen atoms diffusion barrier between the oxidation layers. This study on the oxidation and ablation mechanism of the SiC surface at the atomic scale would provide insight into understanding thermal oxidation behavior and the design of ceramic materials.

Boosting photocatalytic nitrogen fixation performance by adjusting the intramolecular D-A structure and band gap of thiophene-based COFs

Herein, we successfully synthesized two photoactive donor–acceptor (D-A) covalent organic frameworks by incorporating electric-deficient triazine and electric-rich benzotrithiophene moieties into the framework. The introduction of sulfur atom and triazine unit significantly change the intrinsic band gap of JLNU-COFs, this leads to an expanded range of light absorption, encompassing wavelengths from ultraviolet to visible. The narrow band gap of JLNU-311 allows for efficient utilization of visible light while maintaining the thermodynamic activity required for nitrogen reduction within appropriate energy bands. JLNU-311 modified with strong electron absorbing groups has higher activity to NH3 production without co-catalyst or sacrificial agent, and yield can reach 325.6 µmol/g/h. Theoretical calculation further confirm that acceptor structure can effectively regulate the band gap width, promote the adsorption, dissociation and protonation of N2 molecules on JLNU-COFs, and thus reduce the energy barrier of photocatalytic nitrogen reduction reaction (PNRR). Therefore, this study provides an effective strategy for design of active nitrogen fixing photocatalysts.

Balanced adsorption and oxidation in a porous P, N-doped carbon prepared by melt-salt-mediated strategy for enhanced fenton-like reaction

The activation of persulfate oxidation processes using carbon-based catalysts is attractive for eliminating persistent aromatic organic pollutants in wastewater treatment. Herein, N and P co-doped carbonaceous (NPC) catalysts with an ultrahigh surface area were synthesized using a melt-salt-mediated strategy, employing Zeolitic Imidazolate Framework-8 as a self-sacrificing template. The NPC(1:1) carbon, prepared under optimized conditions, exhibited the highest surface area of 2001.5 m2/g, characterized by the highest number of defects and a high dispersion of N (1.89 %) and P (0.30 %) atoms on the carbon. This carbon catalyst exhibited a high capacity for adsorption and potential for activating persulfates in the removal of p-Nitrophenol (p-NP). Experimental data indicate a balance between adsorption and oxidation in the NPC(1:1)/PDS/p-NP system, with the highest catalytic removal rate achieved through moderate pre-adsorption of p-NP. Evidence from quenching, electron paramagnetic resonance (EPR), and amperometric i-t experiments suggests that the NPC(1:1)/PDS system primarily degrades p-NP through an electron transfer pathway. Defects in carbon and graphitic N were identified as catalytic sites. These defects resulted in an electron-deficient state, which leads to the activation of PDS and graphitic N was more reactive than both pyridinic and pyrrolic N in the adsorption of PDS molecules. Additionally, P-containing groups such as C-P-O, C-O-P, and C3-P were pinpointed as active sites on the carbons through DFT calculations. The intermediates during p-NP degradation were identified, and possible degradation pathways were proposed. A toxicity analysis indicated a significant reduction in overall toxicity following the oxidation treatment. This study provides innovative insights into the balance between adsorption and catalytic activity in porous carbon-activated persulfate oxidation reactions, thereby aiding in the development of enhanced oxidation catalysts for environmental remediation.

Effects of Cosolvent on the Intermolecular Interactions between an Analyte and a Gold Nanostar Surface Studied Using SERS.

For surface-enhanced Raman scattering (SERS), reproducible solution-phase results are typically obtained using nanoparticles functionalized with surface-stabilizing molecules that can prevent the adsorption of analyte molecules with surface affinities lower than those of the stabilizing agent. Herein, we investigate the effects of intermolecular interactions between a nonthiolated analyte and cosolvent to facilitate and modulate analyte adsorption to gold nanostars. SERS, extinction spectroscopy, transmission electron microscopy (TEM), and density functional theory (DFT) calculations are employed in this regard. Tetrahydrofuran (THF) is utilized as a cosolvent in water to facilitate the detection of acetylsalicylic acid (aspirin) on anisotropic gold nanoparticles. Intermolecular interactions between the analyte, solvent, and surface are modulated by changing the solution composition to understand how THF facilitates the SERS detection of aspirin in THF-water cosolvents. SERS signals for 5 mM aspirin arise only in the presence of THF at and above 60 mM, while no signal with or without THF below 60 mM is observed. SERS detection of aspirin is hypothesized to depend on THF forming a hydrogen-bonded complex with aspirin that reduces aspirin hydrophobicity, thus stabilizing the acid form of the molecule and allowing it to weakly interact with the gold nanoparticles. The aspirin-THF complex adsorbs to the gold surface through π-orbital overlap between the aromatic ring and gold, where additional THF weakens orbital overlap. Understanding the mechanism by which organic cosolvents facilitate the SERS detection of nonthiolated analytes such as aspirin, in aqueous media, allows other cosolvents, nonthiolated analytes, and other surfaces to obtain a SERS signal in a variety of systems.

Alkali Metal‐Doped Fullerenes as Hydrogen Storage—A Quantum Chemical Investigation

AbstractThe quest for alternative energy sources has been spurred by the drawbacks and environmental risks of fossil fuels, with hydrogen emerging as a viable contender. But finding materials that can effectively store hydrogen with the best adsorption energy is a major obstacle to building a hydrogen‐based economy. As a result, a significant amount of research has been conducted worldwide to examine fullerene's (C60) potential for hydrogen adsorption. The results of extensive DFT calculations are presented here, pertaining to the adsorption of hydrogen molecules onto fullerenes doped with alkali metals, namely Rubidium (Rb), Ceasium (Cs), and Fransium (Fr). The study analyzes a number of parameters, such as global properties, electronic, optical, and surface annihilation energy. These analyses are performed using the Gaussian 09 simulation package with the 6–31G/B3LYP level of theory DFT methodology. The findings show that an exothermic process is involved in the adsorption of hydrogen onto fullerene doped alkali elements, as evidenced by the negative adsorption energy. The attractive interactions between the polarized dipole of hydrogen molecules and the surface dipole of doped fullerenes can be the cause of this exothermicity. These results imply that fullerenes decorated with alkali metals are promising as likely hydrogen storage media.

Nitrogen-Doped Borophene Quantum Dots: A Novel Sensing Material for the Detection of Hazardous Environmental Gases

Toxic gases emitted by industries and vehicles cause environmental pollution and pose significant health risks which are becoming increasingly dangerous. Therefore, the detection of the toxic gases is crucial. The development of gas sensors with high sensitivity and fast response based on nanomaterials has garnered significant interest. In this work, we studied the adsorption behavior of B9− wheel structures of pristine and nitrogen functionalized borophene quantum dots for major hazardous environmental gases, such as NO2, CO2, CO, and NH3. The self-consistent-charge density-functional tight-binding method (SCC-DFTB) method was performed to investigate structural geometries, the most favorable adsorption sites, charge transfer, total densities of states, and electronic properties of the structures before and after adsorption of the gas molecules. Based on calculated results, it was found that the interaction between the borophene quantum dots and the gas molecules was chemisorption. The functionalized nitrogen atom contributed to impurity states, leading to higher adsorption energies of the functionalized borophene quantum dots compared to the pristine ones. Total densities of states revealed insights into electronic properties of gas molecules adsorbed on borophene quantum dots. The nitrogen-doped borophene quantum dots demonstrated excellent performance as a sensing material for hazardous environmental gases, especially CO2.

Preparation of attapulgite nanoparticles modified polypropylene adsorption membrane and its application in small molecular pollutant adsorption

In this study, a novel surface covalent reaction method was used to modify attapulgite nanoparticles on the surface of polypropylene adsorption membrane to adsorb various small molecular pollutants for the first time. The surface covalent reaction method has the advantage of step control. Therefore, the uniformity and stability of attapulgite nanoparticles can be ensured, and then could effectively improve the adsorption performance of polypropylene adsorption membrane. On the other hand, compared with various materials modified on the surface of polypropylene adsorption membrane currently, attapulgite nanoparticles has the characteristics of low cost and environmental friendliness, which is more conducive to the large-scale practical application. The polypropylene adsorption membrane modified with attapulgite nanoparticles was characterized by field emission scanning electron microscopy, fourier transform infrared spectrometer and X-ray diffractograph, and it was confirmed that the attapulgite nanoparticles was successfully modified on the surface of the polypropylene adsorption membrane. The experimental results showed that the adsorption capacities of polypropylene adsorption membrane modified with attapulgite nanoparticles could reach 11.53 mg/g, 8.7 mg/g and 5.78 mg/g for cyromazine, malachite green and dagenan respectively within 10 s. In the case of the above three analytes, the minimum detected concentration could reach 0.02 mg/mL, and the relative standard deviation was about 10 %. At the same time, the adsorption performance of polypropylene adsorption membrane modified with attapulgite nanoparticles did not decrease significantly after 50 cycles. A standard recovery of 76.8 % − 89.5 % and a relative standard deviation of 7.2 % − 15.2 % were obtained by using the polypropylene adsorption membrane modified with attapulgite nanoparticles to adsorb cyromazine in cucumber skin samples, indicating that the polypropylene adsorption membrane modified with attapulgite nanoparticles has the ability to treat complex samples.