Calculated Adsorption Energies Research Articles

Investigation of the adsorption behaviors of novel Au3 cluster decorated arsenene nanosheets towards thiophene and methanethiol detection: A DFT study

First principles calculations were carried out to describe the interactions between Aun-arsenene nanosheets and methanethiol/thiophene molecules. Both Au-arsenene and Au3-arsenene nanosheets exhibit smaller band gap than the pure arsenene system due to the emergence of new energy bands near the Fermi level. Thus, the conductivity and sensor capabilities are significantly enhanced for the Au functionalized arsenene nanosheets. Calculated formation energies of −2.38 eV and −5.37 eV for Au-arsenene and Au3-arsenene nanosheets indicate their structural stability. The adsorption of methanethiol and thiophene molecules on the Au-arsenene substrates spontaneously occurs due to the negative calculated adsorption energies. Besides, thiophene molecule exhibits the highest adsorption energy (−0.52 eV) on the Au-arsenene substrate through its S atom strongly connected to the Au atom. The moderate adsorption energies indicate the shorter recovery times for sensing applications. Our work sheds light on the exploration of Au-arsenene as an effective candidate for sensing methanethiol and thiophene molecules.

Synthesis and characterization of magnetic aluminum metal-organic frameworks encapsulated with chitosan and carboxymethyl cellulose for effective elimination of atrazine from aqueous solutions: Adsorption evaluation, DFT calculations and Box-Behnken design optimization

The discharge of herbicides is a primary contributor to water contamination, presenting significant environmental and public health hazards. Encapsulating herbicides in a chemical compound called MAl-MOF/CS-CMC hydrogel bead (MACC) made from magnetic aluminum metal-organic frameworks (MAl-MOF) and crosslinked with chitosan (CS) and carboxymethyl cellulose (CMC) shows promise for potential use. The research successfully developed and examined MACC microspheres, utilizing various analytical techniques including PXRD, FESEM, TEM, FT-IR, and XPS. The efficiency of MACC in eliminating atrazine (ATZ) from wastewater was also simulated. Additionally, density functional theory (DFT) was employed to assess the electrical characteristics, reactivity, and arrangement of ATZ at a structural level. The results of the DFT analysis demonstrate a significant relationship between the locations of nucleophilic and electrophilic attacks and the molecular orbitals of the HOMO and LUMO. Using MACC as an adsorbent provides considerable advantages due to its expansive surface area of 860.92 m2/g and a pore size of 1.48 nm, meeting the mesoporous classification criteria outlined by IUPAC standards. In addition, it possesses a pore volume of 1.22 cm3/g. Nevertheless, following the adsorption procedure, the pore volume reduced to 0.78 cm3/g, and the surface area decreased to 650.42 m2/g. Several factors contributing to the capacity to attract and retain substances were analyzed. These factors encompass temperature, duration of contact, quantity of the attracting substance, initial atrazine (ATZ) concentration, and solution pH. The primary method of adsorption that was determined is chemisorption, as evidenced by the calculated adsorption energy of 29.3 kJ per mole. The thermodynamic analysis indicates that the adsorption of ATZ by the micropores of MACC occurs spontaneously and is characterized as endothermic, as evidenced by the positive ΔHo value and negative ΔGo value. It has been proposed that a range of adsorption mechanisms, including chemisorption, π-π interactions, pore filling, hydrogen bonding, and electrostatic interactions, may be responsible for removing the herbicide from the MACC material.

Structural and energetic properties of cluster models of anatase-supported single late transition metal atoms: a density functional theory benchmark study.

Single-atom catalytic systems constitute an intriguing research topic due to their inherently different chemical behavior as compared to classic heterogeneous catalysts. In this study, cluster systems representing single late transition metal atoms adsorbed on anatase were constructed starting from previously generated periodic models and subjected to a density functional theory (DFT) benchmark study. The ability of different density functional approximations representing all rungs of the Jacob's Ladder classification to accurately describe bond lengths and adsorption energies was assessed for these clusters with the aim of revealing the functional that allows to retain the structural characteristics of the initial periodic system, while also delivering reliable energetics. In this regard, our results indicate that optimisation of the clusters with the meta-GGA functionals TPSS or RevTPSS provides the lowest mean unsigned error and root-mean-square deviations with respect to the periodic models. Moreover, these functionals and, to a slightly lesser degree, PW91 were also found to provide adsorption energies that are statistically the least deviating from the CCSD(T) reference data. More complex hybrid functionals appear to be performing less well. Cluster geometries were determined at the Kohn-Sham DFT level using the LANL2DZ basis set for the transition metals and the Pople 6-31G(d) basis set for O and H. The density functional approximations considered were SVWN, PBE, BP86, BLYP, PW91, TPSS, RevTPSS, M06L, M11L, B3LYP, PBE0, M06, M06-2X, MN15, ωB97X-D, CAM-B3LYP, M11, and MN12-SX. Reference adsorption energies of the metals on the support cluster were obtained at the CCSD(T)/LANL2TZ (transition metals)/6-311 + + G(d,p)//RevTPSS/LANLD2DZ (transition metals)/6-31G*. Besides the above-mentioned functionals, energy calculations using the double-hybrid functionals, DSDPBEP86, PBE0-DH, and B2PLYP, were also performed. All adsorption energy calculations were carried out on the RevTPSS geometries.

Unveiling the adsorption mechanism of propanehydrazine derivatives on magnesium oxide surface: Insights from computational approach

The use of green and effective inhibitors for preventing metal oxide (MgO) corrosion in industrial applications is highly significant in promoting environmental protection and sustainable development. This study delves into the adsorption behavior and interfacial mechanism of environmentally friendly inhibitor derived from propane hydrazine (PH) on MgO surface. Specifically, PH1, PH2, PH3, and PH4 were explored for their effectiveness in preventing corrosion by using advanced theoretical simulations-based density functional theory (DFT) for assessing the reactivity and adsorption characteristics. The study considered a detailed exploration of local and global reactivity descriptors, providing insights into the inhibitors’ reactivity and adsorption abilities in both isolated and adsorbed states. These findings focus more in the mechanisms underlying organic-inorganic interactions and present promising prospects for further development and application. Using first-principles DFT calculations alongside quantitative molecular surface analyses, we examined the adsorption patterns of PHs on the MgO(100) surface. These investigations are boosted by the application of independent gradient model (IGM) framework, providing robust verification of PHs' adsorption behavior on MgO(100) surface. Our calculations reveal a substantial decrease in the energy gap following complex formation, suggesting that charge density changes occur upon interaction with MgO surfaces, thereby facilitating direct electron transfer in all the studied systems. Noreover, the results highlight the crucial role of intermolecular interactions in boosting the interaction between PHs and the [Mg(H2O)6]2+ cation. First-principles DFT calculations show that all PH molecules consistently display parallel adsorption on the MgO surface, where the oxygen atoms form bonds with adjacent magnesium atoms. The bond lengths vary from 2.18 to 2.35 Å when PHs bind to the Mg atoms in parallel orientations through the oxygen atom, suggesting a stable parallel arrangement for PH molecules on the MgO surface. The calculated adsorption energy (Eads) varies in the following order: MgO-PH3 (−815.14 Kcal mol−1) > MgO-PH2 (−803.85 Kcal mol−1)) > MgO-PH4 (−695.38 Kcal mol−1) > MgO-PH1 (−125.77 Kcal mol−1). This trend indicates that parallel interactions enhance the adsorption behavior and binding of PH compounds through inter- and intra-molecular interactions, resulting in the PHs being centered at specific sites on the MgO surface. The potential enhancement in electrochemical properties is believed to stem from the synergistic interaction between the PHs and the MgO surface, which theoretically allows for a precise adjustment of their adsorption and interaction within the composite structure. This understanding provides a fundamental framework for examining the complex interfacial dynamics between inhibitor structures and elucidating how these molecular interactions influence the selection of corrosion inhibitors and their adsorption behaviors on the corrosion layer's surface, rather than on metallic Mg.

Group VIII Transition Metal (Fe, Ru & Os) Embedded Graphitic Carbon Nitride as an Acetone Sensor: A First Principle Investigation

This study investigates the acetone sensing behavior of pristine graphitic carbon nitride (gCN) and group VIII transition metal (Fe, Ru & Os) embedded gCN monolayer using DFT calculations. Key structural and electronic properties such as adsorption energy, band structure, and density of states (DOS) have been examined. The calculated adsorption energy of pristine gCN is −1.32 eV, which improves to –3.52, −2.75, and −1.73 eV for Fe, Ru, and Os embedded gCN, respectively. The band structure also indicates a reduction in the band gap of gCN after acetone adsorption due to the introduction of Fe, Ru, and Os. Furthermore, after the adsorption of acetone, the DOS values exhibit a significant increase from 13.48 eV−1 for pristine gCN to 439, 423, and 332 eV−1 for Fe, Ru, and Os embedded gCN, respectively.

Theoretical insights of 2D Fe3GeTe2/In2Se3 multiferroic vdW heterostructure based gas sensors for high-performance NO detecting

The impact of the harmful gas NO on the atmospheric environment cannot be ignored, so it is necessary to develop efficient gas sensors to detect and absorb NO at room temperature. In this work, we systematically explored the electron transport properties and gas sensing properties of Fe3GeTe2, In2Se3 monolayers and its multiferroic van der Waals (vdW) heterostructures of Fe3GeTe2/In2Se3 for detecting NO by using density functional theory and nonequilibrium Green's function methods. The calculated adsorption energies, electron localisation functions, band structures and density of states indicate that its a chemisorption for the adsorption of NO on Fe3GeTe2 and a physisorption on In2Se3, while the specific adsorption style is highly dependent on the stacking and molecular adsorption sites of different Fe3GeTe2/In2Se3 structures. In addition, the pristine Fe3GeTe2 monolayer and Fe3GeTe2/In2Se3 based nanodevices realized a significant anisotropy for electron transport along the zigzag and armchair directions, and their anisotropic maximum current ratios in the zigzag to armchair directions were 1.90 and 1.89. Meanwhile, the NO sensitivity ratio of Fe3GeTe2 and Fe3GeTe2/In2Se3 based gas sensors can be up to 79 % and 107 %, respectively. This highlights a notably superior gas-sensitive performance of the Fe3GeTe2/In2Se3 heterostructure compared to the Fe3GeTe2 monolayer gas devices. These findings provide valuable references for the application of multiferroic heterostructures in the field of gas sensors.

Designing Mo-based transition metal dichalcogenides for sustainable hydrogen production: Anionic substitution and DFT insight

Anionic substitution is an effective approach to optimize the catalytic activity of Mo based transition metal dichalcogenide (TMD)- MoS2 towards hydrogen evolution reaction (HER). By optimizing the S-to-Se ratio, materials with the ideal Gibbs free energy of hydrogen adsorption (ΔGH) values are synthesized (MoS2, MoS1.4Se0.6, MoS1.2Se0.8, MoSSe, MoSe2) and their HER performance is examined in 0.5 M H2SO4 solution. Density functional theory calculations of hydrogen adsorption energy on the surface of the electrocatalysts show that Se substitution facilitates electron transfer between the catalyst surface and the hydrogen donor, thereby lowering the additional potential required for water splitting, making MoS1.2Se0.8 the most favorable HER electrocatalyst with the lowest value of adsorption energy. Further enhancement in the electrocatalytic activity of mixed anion TMDs has been achieved by the incorporation of carbon nanotubes (CNTs). MoS1.2Se0.8-CNT nanocomposite exhibits superior HER performance with an overpotential of 118 mV and a Tafel slope of 63 mV/decade as compared to MoS1.2Se0.8 sample owing to the synergetic effect from CNTs and MoS1.2Se0.8.

Adsorption of phenolic compounds on polymeric ionic liquids: Adsorption isotherms interpretation and thermodynamic study

This study describes the thermodynamic assessment and steric interpretation of the 4-nitrophenol (4-NP) and 4-chlorophenol (4-CP) adsorption on polymeric ionic liquids (PILs) using advanced statistical physics model. A monolayer model with a single energy level was employed to elucidate the adsorption mechanisms of these phenolic compounds. The results showed that the orientation of 4-NP and 4-CP on the surface of this adsorbent was a combination of parallel and non-parallel configurations at the tested adsorption temperatures. The values of the adsorption capacities at saturation were 484.7 and 406.7 mg/g for4-NP and 4-CP, respectively. The modelling results indicated that more active sites from PILs surface were involved in the removal of 4-nitrophenol than those required for the 4-chlorophenol adsorption. The calculation of adsorption energies confirmed that the adsorption of 4-NP and 4-CP on PILs was exothermic and driven by physical forces involving hydrogen bonds and van der Waals forces. Three thermodynamic functions were analyzed to complete the macroscopic analysis of the adsorption mechanism for these relevant phenolic contaminants.

First-principles study of O3 molecule adsorption on pristine, N, Ga-doped and -Ga-N- co-doped graphene

The adsorption of O3 molecules (ozone) on graphene, N-doped graphene, Ga-doped graphene, and -Ga-N- co-doped graphene with an emphasis on O3 detection was examined in this work. The physical characteristics of -Ga-N-co-doped graphene are significantly altered upon O3 adsorption, which makes it a suitable choice for O3 detection molecular sensors. The interaction between the O3 molecule and the adsorbent is explained on the basis of their adsorption energy, adsorption distance and charge transfer. It was found that the adsorption of ozone molecules on the -Ga-N- co-doped graphene was more favorable in energy than that on the pristine one, representing the superior sensing performance of -Ga-N- co-doped system. In our work, we estimated the charge transfer between the O3 molecule and doped graphene nanostructures based on Mulliken population analysis. The calculated adsorption energy value shows the ozone molecule more firmly adsorbs on the surface of -Ga-N- co-doped graphene nanostructures (Eads = –1.74 eV) than that of pristine graphene (Eads = –0.41 eV), deriving from a stronger covalent bond between the ozone molecule and the -Ga- N- co-doped graphene nanostructures. Our findings thus suggest that -Ga-N- co-doped graphene could be a highly efficient gas sensor device for O3 detection in the environment.

Selective Separation of C8 Aromatics by an Interpenetrating Metal-Organic Framework Material.

O-xylene (OX) is an important chemical raw material, but it is often produced in mixtures with other C8 aromatics. Similar physicochemical properties of the C8 isomers make their separation and purification very difficult and energy intensive. There is an unmet need for an adsorbent that would be effective for the separation of OX from the other C8 isomers. This work reports a three-dimensional interpenetrated metal-organic framework, SYUCT-110, that interacts with each of the single-component C8 isomers to form. The selectivity of C8 aromatic hydrocarbons was determined through liquid-phase batch uptake experiments. The results revealed that the selectivity order was OX > PX > MX > ethylbenzene (EB). The selectivity values were found to be 2.63, 1.58, 5.51, 3.71, 1.86, and 3.02 for OX/MX, OX/PX, OX/EB, PX/MX, MX/EB, and PX/EB, respectively. The adsorption capacity of OX was 71 mg/g. Grand Canonical Monte Carlo simulations were used to study the C8 adsorption sites, revealing that π···π interactions are the main reason for the observed adsorption selectivity. The adsorption energy calculation results also verified the selectivity of SYUCT-110 for the synthesis of OX.

Insights into the Effect of a Microwave Field on the Properties of Modified γ-Alumina: A DFT Study

γ-Alumina is often used as a support for hydrodesulfurization catalysts due to its excellent performance. During the catalytic reaction, the strong surface acidity of γ-alumina can induce a strong interaction between the active phase and the support. The reaction activity of the catalyst can be affected by changing the present mode of the active phase on the surface of the support. The (110) crystal plane, acting as the strongest acidity plane of γ-alumina, was selected for modification. The supports modified with boron and phosphorus were successfully constructed, and the acid strengths were quantified by simulating the adsorption of the relevant probe molecules: pyridine in correlation with surface electronic properties via density functional theory. The surface adsorption energy calculation shows that the boron-modified surface is able to moderately reduce the adsorption capacity of alumina, while that of the surface modified by phosphorus is found to be enhanced over the sites of a tetrahedral coordination structure; however, at the other unsaturated Al sites, this is obviously reduced. The results of introducing electric fields imply that applying horizontal electric fields changes the surface acidity of alumina under the premise of a stable structure. With the enhancement of the horizontal electric fields, the adsorption capacity of tetra-coordination sites on the original surface gradually decreases, while those of the others gradually increases. However, for the boron-modified surface, introducing horizontal electric fields can reduce the adsorption capacity of all sites. Hence, microwave-electric-field-assisted modification of B further reduces the surface acidity of alumina, making it beneficial for deep hydrodesulfurization reactions.

A Study Based on the First-Principle Study of the Adsorption and Sensing Properties of Mo-Doped WSe2 for N2O, CO2, and CH4

As industry continues to develop rapidly, the greenhouse effect is becoming increasingly severe. CO2, CH4, and N2O are the three primary greenhouse gases, making their effective monitoring a crucial step in reducing emissions. This paper investigates the gas sensing performance of Mo-doped WSe2 for these three gases, through a theoretical study. First, using first-principles calculations, the doping behavior of Mo in WSe2 is examined. Subsequently, the adsorption properties of Mo-WSe2 for CO2, CH4, and N2O are analyzed by calculating adsorption energy, charge transfer, the electron localization function (ELF), Hirshfeld partition (IGMH), and the density of states (DOSs), culminating in an analysis of its sensing properties. The results indicate that when Mo is positioned above the upper Se atom, the structure is most stable. Therefore, this position is selected as the optimal adsorption site for studying the adsorption of the three gases. The adsorption energies for CO2, CH4, and N2O are 1.349 eV, −1.194 eV, and −0.528 eV, respectively, with corresponding charge transfers of 0.418, 0.450, and 0.115. In the N2O and CO2 adsorption systems, significant adsorption energy and charge transfer are observed, leading to relatively better adsorption compared to the CH4 system. Additionally, considering the adsorption performance, Mo-WSe2 demonstrates good sensor response and desorption times for N2O and CO2 at temperatures above 298 K. The findings of this research provide theoretical guidance for the application of Mo-WSe2 as a gas sensing material for detecting greenhouse gases.

Design of hydrogen sensor relying on Pd-MWCNT/WO3 sensing materials for selective and rapid hydrogen detection

In this investigation, hydrogen sensors were designed based on multi-walled carbon nanotubes (MWCNT) and Pd loaded on WO3 nanosheets by means of hydrothermal synthesis and impregnation reduction. First, WO3 with different morphologies were synthesized, including zero dimension (0D) nanoparticles, one dimension (1D) nanowires and two dimension (2D) nanosheets. After testing, the 2D-WO3 material was selected as the substrate material to form final Pd-MWCNT/WO3 composites. Outstandingly, Pd-MWCNT/WO3 sensor exhibited greatest sensitivity with high response value (371.13), fast response/recovery time (1/4 s) to 1000 ppm hydrogen at 175℃, excellent selectivity and reproducibility. Furthermore, the corresponding hydrogen sensing mechanism was proposed combining with DFT calculation of hydrogen adsorption energy. This was the first report on designing a novel ternary Pd-MWCNT/WO3 composites sensor applied to hydrogen detection and the first time to calculate the hydrogen adsorption energy of Pd-MWCNT/WO3.

Adsorption behavior and mechanism of NH2-MIL-101(Cr)@COFs@SA composite adsorbent for tetracycline removal

Herein, we employed a rational approach to develop a hydrogel composite material by encapsulating NH2-MIL-101(Cr)/covalent organic frameworks (COFs) in sodium alginate (SA) to effectively capture of tetracycline (TC). Experimental tests and various characterizations (including Fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron spectroscopy (SEM), Brunauer-Emmett-Teller (BET), and X-ray photoelectron spectroscopy (XPS)) confirmed that the NH2-MIL-101(Cr)@COFs@SA composite exhibited a more robust, multilayer pore structure with abundant active functional groups. Under conditions of 298 K and pH = 7, the NH2-MIL-101(Cr)@COFs@SA adsorbent demonstrated remarkable TC adsorption capability, achieving a removal rate of 96.38 % in 120 min and a qmax of 252.6 mg/g at 298 K by Langmuir model. Kinetic analysis indicated that the interaction between TC and NH2-MIL-101(Cr)@COFs@SA follows a pseudo-second-order model, suggesting that chemisoption governs the process. The Langmuir model and thermodynamic analysis suggested that TC adsorption follows a monolayer sorption pattern and is spontaneous and exothermic. Even in the presence of other ions, NH2-MIL-101(Cr)@COFs@SA maintained high efficiency for TC adsorption, demonstrating superior selectivity. NH2-MIL-101(Cr)@COFs@SA demonstrated remarkable recyclability, with only a minimal reduction in the removal efficiency (85.5 % and 142 mg/g) after 10 cycles of adsorption and regeneration. Various analytical techniques, including FTIR spectroscopy, SEM, EDX, XPS, and density functional theory (DFT) calculations of adsorption energy were used to elucidate the TC adsorption mechanisms by NH2-MIL-101(Cr)@COFs@SA. The adsorption process primarily involved π-π stacking, hydrogen bonding, electrostatic interactions, and complexation.

Theoretical Investigation of the Effects of Aldehyde Substitution with Pyran Groups in D-π-A Dye on Performance of DSSCs.

This work investigated the substitution of the aldehyde with a pyran functional group in D-π-aldehyde dye to improve cell performance. This strategy was suggested by recent work that synthesized D-π-aldehyde dye, which achieved a maximum absorption wavelength that was only slightly off the threshold for an ideal sensitizer. Therefore, DFT and TD-DFT were used to investigate the effect of different pyran substituents to replace the aldehyde group. The pyran groups reduced the dye energy gap better than other known anchoring groups. The proposed dyes showed facile intermolecular charge transfer through the localization of HOMO and LUMO orbitals on the donor and acceptor parts, which promoted orbital overlap with the TiO2 surface. The studied dyes have HOMO and LOMO energy levels that could regenerate electrons from redox potential electrodes and inject electrons into the TiO2 conduction band. The lone pairs of oxygen atoms in pyran components act as nucleophile centers, facilitating adsorption on the TiO2 surface through their electrophile atoms. Pyrans increased the efficacy of dye sensitizers by extending their absorbance range and causing the maximum peak to redshift deeper into the visible region. The effects of the pyran groups on photovoltaic properties such as light harvesting efficiency (LHE), free energy change of electron injection, and dye regeneration were investigated and discussed. The adsorption behaviors of the proposed dyes on the TiO2 (1 1 0) surface were investigated by means of Monte Carlo simulations. The calculated adsorption energies indicates that pyran fragments, compared to the aldehyde in the main dye, had a greater ability to induce the adsorption onto the TiO2 substrate.

Curvature-Induced Electron Spin Catalysis with Carbon Spheres.

Here, we report curvature-induced electron spin catalysis by using solid carbon spheres as catalysts, which were synthesized using positive curvature molecular hexabromocyclopentadiene as a precursor molecule, following a radical coupling mechanism. The curvature spin of carbon is regarded as an overlapping state of σ- and π-radical, which is identified by the inverse Laplace transform of pulse-electron paramagnetic resonance. The growth mechanism of carbon spheres abiding by Kroto's model, is supported by the density functional theory study of thermodynamics and kinetics calculations. The solid carbon spheres present excellent catalytic behaviour of oxidation coupling of amines to form corresponding imines with the conversion of >99%, selectivity of 98.7%, and yield of 97.7%, which is attributed to the predominantly curvature-induced electron spin catalysis of carbon, supported by the calculation of oxygen adsorption energy. This work proposes a view of curvature-induced spin catalysis of carbon, which opens up a research direction for curvature-induced electron spin catalysis.

Curvature‐Induced Electron Spin Catalysis with Carbon Spheres

Here, we report curvature‐induced electron spin catalysis by using solid carbon spheres as catalysts, which were synthesized using positive curvature molecular hexabromocyclopentadiene as a precursor molecule, following a radical coupling mechanism. The curvature spin of carbon is regarded as an overlapping state of σ‐ and π‐radical, which is identified by the inverse Laplace transform of pulse‐electron paramagnetic resonance. The growth mechanism of carbon spheres abiding by Kroto’s model, is supported by the density functional theory study of thermodynamics and kinetics calculations. The solid carbon spheres present excellent catalytic behaviour of oxidation coupling of amines to form corresponding imines with the conversion of >99%, selectivity of 98.7%, and yield of 97.7%, which is attributed to the predominantly curvature‐induced electron spin catalysis of carbon, supported by the calculation of oxygen adsorption energy. This work proposes a view of curvature‐induced spin catalysis of carbon, which opens up a research direction for curvature‐induced electron spin catalysis.

Insight into the degradation mechanism of mixed VOCs oxidation over Pd/UiO-66(Ce) catalysts: Combination of operando spectroscopy and theoretical calculation

Herein, Pd/UiO-66(Ce) catalysts were successfully synthesized by N2H4, H2, and NaBH4 reduction methods with UiO-66(Ce) as support. The best catalyst was selected via utilizing o-xylene as the probe molecule, and its degradation performance of mixed VOCs was further investigated. It was found that the reduction methods greatly influenced the size of Pd nanoparticles, the state of surface Pd, and the support structure in the catalysts, which in turn affected their catalytic performance. Among them, Pd/UiO-66(Ce)-Na exhibited the best o-xylene degradation activity (T90 = 192 °C) due to its smaller average Pd particle size (Pd Average = 2.93 nm) and higher surface Pd0 content (Pd0/Pdtotal = 0.79). The performance and interaction of Pd/UiO-66(Ce)-Na catalyst for degradation of mixed VOCs (o-xylene and toluene/benzene) were investigated by DFT adsorption energy calculation, in situ DRIFTS and GC–MS. Results suggested that the single adsorption energy of o-xylene was −1.20 eV, while in the system with toluene/benzene, the adsorption energy decreased to −0.78 and −0.6 eV, respectively. This showed the competitive adsorption effect between benzene and o-xylene was stronger than that between benzene and o-xylene. Finally, combined with in situ DRIFTS and GC–MS, the degradation path of mixed components was analyzed and studied systematically, and the mechanism of intermolecular interaction of benzene in the degradation process of mixed components was further revealed.

Photocatalytic CO2 Reduction to Ethanol by ZnCo2O4/ZnO Janus Hollow Nanofibers.

Photocatalytic carbon dioxide (CO2) reduction for high-value hydrocarbon fuel production is a promising strategy to tackle global energy demand and climate change. However, this technology faces formidable challenges, primarily stemming from low yield and poor selectivity of C2 products of the desired hydrocarbon fuels. This study reported ZnO/ZnCo2O4 Janus hollow nanofibers (ZnO/ZCO JHNFs) prepared by electrospinning and atomic layer deposition. Photocatalytic tests revealed an ethanol yield of 4.99 μmol g-1 h-1 for ZnO/ZnCo2O4 JHNFs, surpassing mixed ZnO/ZnCo2O4 nanofibers (ZnO/ZCO NFs) by 4.35 times and pure ZnO by 12.7 times. The selectivity of 58.8% is 2.38 and 4.49 times higher than those of ZnO/ZnCo2O4 NFs and ZnO, respectively. These enhancements are attributed to efficient carrier separation facilitated by the ordered internal electric field of the Z-scheme heterojunction interface, validated by the energy band evaluations from experimentation and density functional theory (DFT) simulations and charge separation characterizations of photocurrent, impedance, and photoluminescence spectra. The Janus structure also effectively exposes the surface of ZnCo2O4 to CO2 molecules, increasing the active site availability, as confirmed by BET nitrogen adsorption/desorption, temperature-programmed desorption tests, and DFT adsorption energy calculations. This study proposes a novel approach for efficient photocatalytic hydrocarbon fuel production, with potential applications in energy and climate crisis mitigation.

Specific adsorption of antiviral drugs on ionic liquid-modified metal–organic framework: Adsorption behavior, mechanism, and DFT analysis

As emerging contaminants, antiviral drugs (ATVs) in water pose an increasing threat to human health and the ecosystem. Using specific and selective adsorption methods to remove ATVs remains challenging due to their trace concentration in real matrices. In this study, pyridine ionic liquid ([BPy][Sal])-modified metal–organic framework (MOF), a type of novel material, was synthesized as [BPy][Sal]@MOF to adsorb ATVs with different molecular structures, i.e., Arbidol (Arb) and Favipiravir (Fav). Arb adsorption followed the pseudo-second-order model, indicating that chemisorption is the dominant process. The Langmuir isothermal model showed that the maximum adsorption capacities toward Arb and Fav were 506.9 and 35.3 mg g−1, respectively, suggesting specific adsorption of Arb on [BPy][Sal]@MOF. Density functional theory (DFT) was used to investigate the specific adsorption mechanism. The molecular electrostatic potential and the intermolecular weak interaction analysis using the DFT method illustrated that the amino hydrogens in MOF could form hydrogen bonds (NHO) with the hydroxyl oxygens in Arb. Simultaneously, the indole ring in Arb could cause π–π interaction with the pyridine ring in [BPy][Sal] part from [BPy][Sal]@MOF. In contrast, the adsorption of Fav only involved π–π interaction between the benzene rings in Fav and the MOF part from [BPy][Sal]@MOF. The adsorption energy and energy gap calculation results verified that the adsorption strength of Arb was higher than that of Fav, and the key role of [BPy][Sal] in [BPy][Sal]@MOF helped achieve specific adsorption was confirmed. [BPy][Sal]@MOF exhibited exceptional recyclability after five adsorption–desorption cycles in environmental waters, demonstrating its excellent adsorption performance in practical applications.