Density Functional Theory Calculations Research Articles

Efficient degradation of Enrofloxacin with novel magnetic MnFe2O4/NiS2 composite as an activator of peroxymonosulfate

The development of highly active and recoverable heterogeneous catalysts for peroxymonosulfate (PMS) activation to remove the persistent presence of antibiotics in aquatic environments, such as Enrofloxacin (ENR), remains a significant challenge. Here, we introduce a pioneering magnetic nanocomposite catalyst, MnFe2O4-NiS2, synthesized via a two-step hydrothermal process, which activates PMS to efficiently degrade ENR. The optimized 0.25MnFe2O4-NiS2/PMS system reached an ENR removal efficiency of 89.9 % within 90 min, outperforming both NiS2/PMS and MnFe2O4/PMS by 5.6 and 2.5 times, respectively. Quenching experiments and electron spin response analysis confirmed SO4•- and •O2– as the primary reactive oxygen species. The enhanced mediated electron transfer capability of the 0.25MnFe2O4-NiS2 nanocomposite improved the redox cycling of Ni (Ⅱ), Mn (Ⅱ) and Fe (Ⅲ) on its surface, as verified by Density Functional Theory calculations. Furthermore, the activation of surface PMS complexes (PMS*) played a crucial role in ENR degradation. The proposed degradation pathways of ENR were confirmed, and toxicity analysis indicated a decrease in intermediate toxicity with the 0.25MnFe2O4-NiS2/PMS system. This study presents an innovative magnetically recoverable, multifunctional catalyst with easy reusability for potential applications in the degradation of organic pollutants.

Structural analysis and theoretical studies of 2-(2-chlorobenzylidene) malononitrile (CS) “a riot controlling agent”

In solvent methanol, malononitrile and 2-chlorobenzaldehyde were stirred in the presence of base piperidine to synthesise the target chemical 2-(2-chlorobenzylidene) malononitrile (CS). The crystal structure of the target compound C10H5ClN2 has been elucidated through X-ray crystallographic analysis. It crystallises in the monoclinic crystal system within the P21 space group, containing four molecules per asymmetric unit. The unit cell dimensions are a = 3.8825(3) Å, b = 21.0202(18) Å, c = 21.3481(18) Å, and β = 95.096(4)°. The phenyl and malononitrile groups, which make up the molecular components, are each planar but slanted towards one another at a dihedral angle of 12.7° (4). Besides this, target molecule is also stabilized by hydrogen bonding, halogen bonding and π stacking interactions. Solid-state structure has been analysed through Hirshfeld surface analysis, including the evaluation of the different energy frameworks, indicating that the molecular sheets are primarily formed by hydrogen bonds and halogen bonds and the stabilization is dominated via the electrostatic energy contribution. Fingerprint plots were carried out to study the relative contribution of noncovalent interactions in the target compound CS. Further, the density functional theory calculations were employed using B3LYP hybrid functional with 6-311++G level basic set to optimize the structural coordinates in gas phase and in different solvents (chloroform, water, and methanol). The chemically active regions of the target compound were identified by the analysis of molecular electrostatic potential surface. Further, from PASS analysis and literature reports, molecular docking of title compounds was carried out with human transient receptor potential ankyrin 1 ion channel (hTRPA1) (PDB-ID 6PQO). ΔGb (docking energy) and inhibition constant was calculated to be −7.53 kcal/mol and 3.33 μM respectively, with the target ion channel.

Turning waste into Wealth: Collaborative enhancement of sucralose degradation and ilmenite aeration purification

Integrating sucralose degradation with the aeration purification of reduced ilmenite presents an untapped opportunity for enhancing aeration efficiency and promoting wastewater utilization. Herein, aeration experiments conducted at 80 °C with a 2 % sucralose concentration yielded an 18 % enhancement in aeration efficiency, a 21.5 % decrease in energy expenditure, and the sucralose content was reduced to 2.5 %. Density functional theory calculations and computational fluid dynamics confirm the formation of Fe-O interactions between sucralose and γ-FeOOH colloids, which produce flocculation, decrease slurry viscosity, and enhance oxygen transfer, thereby improving aeration efficiency. Furthermore, FeCl3, generated during aeration, catalyzes sucralose degradation. This study provides a theoretical foundation and practical experience for the synergistic application of wastewater and mineral processing.

Evaluate the potential adsorption of graphynes (perfect and doped) for nitrogen mustard gas: A first principles study

Density functional theory (DFT) calculations are used to thoroughly examine the reactivity and electronic sensitivity of pristine and BN-doped graphyne (BNG) toward nitrogen mustard (NM). Graphyne’s electrical conductivity is unaffected by the weak adsorption of NM, which occurs via the Cl atom on the material with an adsorption energy of roughly −3.1 kcal.mol−1. In addition to decreasing graphyne’s reactivity and work function, substituting isoelectronic BN linkages for CC linkages enhances the HOMO-LUMO energy gap (Eg). BNG’s electrical conductivity increases when Eg drops from 2.99 to 1.82 eV due to the adsorption of NM. Additionally, a significant change in BNG’s work function results in a variation in the field electron emission current. Lastly, it is anticipated that the desorption of NM from the BNG surface will take a brief recovery time of roughly 0.05 s at room temperature. It has also been demonstrated that NM concentration affects changes in electrical conductivity. The findings also suggest that BNG could be a promising NM sensor.

Removal of phosphate from wastewater using zirconium/iron embedded chitosan/alginate hydrogel beads: An experimental and computational perspective

Adsorptive removal of phosphate plays a crucial role in mitigating eutrophication. Herein, the Zr/Fe embedded chitosan/alginate hydrogel bead (Zr/Fe/CS/Alg) is reported as an effective phosphate adsorbent. This polymer nanocomposite is synthesized by the in-situ reduction of the metals on the polymer matrix. The synthesized adsorbent was characterized by the FTIR, SEM-EDX, TGA, BET, and XPS. The adsorbent showed a maximum phosphate adsorption capacity of 221.72 mg/g at pH 3. The experimental data fit well with the Freundlich isotherm and pseudo-second-order kinetics model, indicating a heterogeneous multilayer surface formation and a chemisorption-dominated adsorption process. Density Functional Theory (DFT) and Monte Carlo (MC) calculations revealed high negative adsorption energy due to the chemisorption of phosphate on the adsorbent. Hence, the major interactions such as electrostatic attraction, hydrogen bonding, and inner-sphere complexation of phosphate adsorption and Zr/Fe/CS/Alg hydrogel beads were investigated from the experimental and computational analysis. The negative values of thermodynamic parameters indicated a spontaneous, exothermic, and less random adsorption process. The synthesized adsorbent exhibited excellent selectivity toward phosphate and maintained 73 % efficiency after six adsorption/desorption cycles. The Zr/Fe/CS/Alg hydrogel beads reduced the phosphate concentration in real wastewater samples from 19.02 mg/L to 0.985 mg/L, suggesting that these nanocomposite hydrogel beads could be a promising adsorbent for real-world applications.

Efficient sodium ion transport enhanced by anionophilic sites in polymer-supported plastic crystal electrolyte for high performance sodium metal anode

The design of sodium metal batteries (SMBs) is seen as an excellent solution to solve the request of next-generation energy storage technologies with high energy density, high safety, low cost, and environmental friendliness. However, the direct use of sodium metal as an anode produces the dendritic sodium, which harms the normal operation of battery. Inspired by solid-state lithium metal batteries, solid-state electrolyte (SSE) designed for SMBs effectively solves this shortcoming. Herein, a novel SSE with mask-based polymer membrane supporting plastic crystal electrolyte with ZIF-67 (MPPZ) is designed. The experimental results and density functional theory (DFT) calculations indicate that the addition of ZIF-67 in MPPZ electrolyte availably fixes TFSI− and achieves high Na+ transference number. Additionally, a protective layer of NaF is formed in situ on the surface of sodium metal to avoid side reactions between Na and MPPZ electrolyte while further guide the uniform deposition of Na. Accordingly, Na||Na symmetric battery with NaF-coated Na metal anode and MPPZ electrolyte has a stable deposition and stripping of Na for 3000 h. The assembled room temperature solid-state sodium-sulfur battery (RTSSSSB) exhibits a good cycle stability. This study provides an innovative thinking for the construction of high performance dendrite-free SMBs.

Investigation of the effect and mechanism on the flotation performance of alkylglycine-based collectors by acyl group

The structure difference of the flotation reagent has a significant influence on its flotation performance. In this work, sodium N-lauroyl glycinate (SNG) was synthesized by introducing an acyl group into sodium N-dodecylglycinate (SN), and was using the collector in the oxide ores flotation. Properties of these two collectors were compared, and the effects behavior and mechanism of introducing the acyl group on the flotation performance of alkylglycine-based collectors to the zinc oxide minerals were systematically investigated. Flotation results proved that the introduction of C = O group into SN barely affected the floatability of smithsonite, hemimorphite and calcite, while the floatability of quartz was greatly reduced. Contact angle tests, surface tension tests, and froth collapse measurements indicated that the introduction of the acyl group into SN could selectively weaken its ability to improve the hydrophobicity of mineral surfaces, reduce its surface tension, adsorption capacity and intensity on the mineral surface, and the froth stability, thereby enhancing its selectivity, consistent with the flotation results. Fourier transform infrared spectroscopy (FTIR) analyses and density functional theory (DFT) calculations revealed that the introduction of the acyl group could increase the cross-sectional area and reduce the charge of the SNG polar groups to selectively weaken the adsorption interaction, particularly by significantly reducing the electrostatic adsorption between SNS and quartz surfaces. These also confirm that SNG is a promising highly selective collector for the flotation separation of zinc oxide minerals.

Simultaneous dehalogenation and oxidation of dichloroacetamide by Cu-modified CoFe-LDH in three-dimensional continuous flow aerated electrocatalytic reactor

Searching for catalysts and degradation systems for synchronous dehalogenation and oxidation of haloacetamides (HAcAms) is pressing. In this study, a novel three-dimensional continuous flow aerated electrocatalytic reactor (3D CFAER) system, which employed Cu-modified CoFe layered double hydroxides (CoFe-LDH) composite/activated carbon as a catalytic particle electrode for the degradation of dichloroacetamide (DCAcAm) was constructed. Under the experiment’s optimal operating parameters, the maximum degradation rate of DCAcAm reached 91.7 %. The superior performance for the degradation of DCAcAm was due to the enhanced electron transfer induced by the modification of Cu in CoFe-LDH. Moreover, Density Functional Theory (DFT) calculations indicated that Cu doping improved the ability of LDH to dissociate water, thereby enhancing its electrocatalytic performance. Scavenger experiments and Electron Paramagnetic Resonance (EPR) results revealed that •OH, O2•– and electrochemical direct dehalogenation were responsible for DCAcAm removal. Additionally, the electrocatalytic stability of the electrode was tested upon repeated use with DCAcAm degradation remaining as high as 81.7 % after five consecutive experiments. More importantly, in 3D CFAER, electrocatalytic treatment lasting 90 min reduced the TOC and COD of the actual chlorine disinfection wastewater by 64.1 % and 74.9 %, respectively. This study provides new theoretical basis and technical support for control of HAcAms.

Immobilization mechanism of heavy metals by crystals and liquid phase during melting treatment of MSWI fly ash

Melting treatment has emerged as a promising technology for managing municipal solid waste incineration (MSWI) fly ash owing to its advantageous features of effective detoxification and volume reduction. The melting treatment of MSWI fly ash involves the immobilization of heavy metals by crystals and liquid phase. Herein, the immobilization mechanism of heavy metals (Cu, Pb and Cd) by the crystals and the liquid phase was investigated using melting experiments, thermodynamic calculations and density functional theory (DFT) calculations. Results demonstrate that the immobilization of heavy metals is influenced by a combination of factors: the reaction of heavy metals, physical encapsulation ability of the liquid phase and chemical fixation ability of both the crystals and the liquid phase. An increase in the content of SiO2 and Al2O3 promotes the conversion of heavy metals oxides into heavy metals chlorides. Furthermore, an increase in the content and polymerization degree of the liquid phase facilitates the physical encapsulation of heavy metals chlorides. The chemical fixation ability of the crystals and the liquid phase differs for Cu and Pb, while Cd cannot be immobilized through chemical fixation. To enhance the immobilization of heavy metals during melting treatment, the chemical composition of MSWI fly ash should be adjusted within the anorthite region of the ternary phase diagram. This study provides valuable insights into the immobilization mechanism of heavy metals by the crystals and the liquid phase during the melting treatment of MSWI fly ash.

Enhanced Absorption Capacity and Fundamental Mechanism of electrospun MIL-101(Cr)-NH2/PAN nanofibrous Membranes for Mo(VI) Removal

Amidst the escalating global concern over heavy metal discharge from industrial effluents, Mo(VI), as a potentially toxic trace element, poses significant risks to human and environmental health. Traditional treatment methods such as biodegradation and ion exchange have low removal efficiency, hence, the efficient removal of Mo (VI) ions from industrial wastewater assumes paramount importance. Emerging materials, Metal-Organic Frameworks (MOFs), have garnered extensive attention in water treatment due to their strong adsorption properties, and MOFs membrane materials are hailed as the most promising adsorbents. Therefore, this study aims to prepare a novel membrane material with high efficiency for the removal of Mo (VI) by loading MOFs into nanofibers. Given the water stability of MIL-101, MIL-101-R(-H, -NH2, -NO2) with different functional groups were prepared and subsequently loaded into PAN nanofibrous for the adsorption of Mo(VI). Adsorption kinetics and isotherm studies revealed PAN/MIL-101(Cr)-NH2 to exhibit superior adsorption performance, achieving a maximum adsorption capacity of 171.81 mg/g. Density functional theory (DFT) calculations and molecular dynamics simulations elucidated the adsorption mechanism, highlighting the role of amino modification in facilitating Mo(VI) adsorption through electrostatic attraction and high reactivity. This work not only offers novel materials and approaches for Mo(VI) wastewater treatment but also advances the industrial application of MOF materials in the domain of heavy metal wastewater treatment.

A DFT study on the sulfur resistance mechanism of elemental mercury catalytic oxidation over Mn-Mo/CNT

The strong sulfur resistance of Mn-Mo/CNT during the process of elemental mercury catalytic oxidation at low temperature has been demonstrated in experiment. However, there remains a dearth of in-depth research on the sulfur resistance mechanism. This work aims to explore the sulfur resistance mechanism through density functional theory (DFT) calculations. The results reveal that SO2 can be effectively oxidized to SO3 through lattice oxygen on the surface of Mn-Mo/CNT. The speed control step is the step of SO3 dissociation, with an energy barrier of 2.50 eV. Additionally, O2 can adsorb onto active sites to supplement the consumed lattice oxygen. The adsorbed O2 can also oxidize SO2, and the highest energy barrier of this reaction is only 0.26 eV. SO3 can further react with the adsorbed Hg0 to form HgSO4, and the speed control step is the step of Hg0 oxidation. Specifically, when Hg0 is adsorbed onto Mo active sites, its energy barrier of speed control step reaches 4.06eV. Whereas, when Hg0 is adsorbed on Mn site, the energy barrier of speed control step reduces to 3.18eV. Generally, the coupling reaction process of Hg0 oxidation and SO2/SO3 conversion over Mn-Mo/CNT is the reason of the promotion in sulfur resistance of this catalyst.

Electrocatalytic degradation of naphthenic acids using reduced graphene oxide modified nickel foam cathode: Role of surface structure and superoxide radical

In this work, the reduced graphene oxide (RGO) modified nickel foam (Ni-foam) was prepared via the hydrothermal reduction self-assembly method and was applied as the cathode for the effective electrocatalytic (EC) degradation of recalcitrant naphthenic acids (NAs) that are abundantly present in the petroleum industrial wastewater. The Ni@RGO cathode has greatly enhanced the production of H2O2 in the system to boost the degradation of 1-adamantanecarboxylic acid (ACA) that was a model NA compound. Results showed that the EC/Fe(III)/Ni@RGO system achieved complete ACA degradation within 15 min due to its elevated H2O2 generation and Fe(III)/Fe(II) circulation, compared to EC/Fe(III)/Ni-foam and EC/Fe(III)/Graphite systems. Interestingly, abundant ·O2– radicals, which were produced in EC/Fe(III)/Ni@RGO system as a key intermediate for 2e- oxygen reduction reaction (ORR), could effectively accelerate the circulation of Fe(III)/Fe(II) to activate H2O2 to generate ·OH for ACA degradation. Results of material characterization, electrochemical analysis and density functional theory (DFT) calculations showed that Ni@RGO cathode has obtained elevated electron transfer efficiency compared to that of Ni-foam cathode. Surface structure of RGO, such as carbon edge and vacancy with specific configuration, residual –COOH oxygenation groups on RGO surface are main catalytic sites to enhance the capacity of 2e- ORR and electron capture processes in the system. This study provides new insights regarding the synthesis process of catalytic electrodes, the influence of carbon-based material structure on catalytic activity, and the critical role of free radicals in the electro-Fenton system with Ni@RGO cathode

S-type Bi2S3/BiOBr heterojunction with robust piezo-photocatalytic dye removal activity: degradation performance and mechanism investigation

In this work, an efficient S-type Bi2S3/BiOBr piezo-photocatalysts was prepared by the decoration of Bi2S3 nanorods on the surface of BiOBr nanosheets. The piezo/photo/piezo-photocatalytic performance of samples were evaluated under the irradiation of ultrasonic and/or simulated-sunlight employing methyl orange (MO) as a target reactant, indicating that above catalytic activity of BiOBr is able to be elevated after Bi2S3 attachment. Particularly, the 10%Bi2S3/BiOBr sample exhibits the optimal catalytic performance. It is worth noting that the 10%Bi2S3/BiOBr sample achieves much higher piezo-photocatalytic MO removal efficiency than its photocatalysis and piezocatalysis, demonstrating a remarkable synergistic improvement between piezocatalysis and photocatalysis with a synergistic enhancement factor (SF) of ∼1.29. The formation of S-type heterojunction in the Bi2S3/BiOBr composite was directly confirmed by the combination of density functional theory (DFT) calculation and in-situ irradiated X-ray photoelectron spectroscopy (ISI-XPS) measurement, elevating the surface separation of generated charges. Meanwhile, the ultrasonic-excited piezoelectric polarization field in BiOBr nanosheets excited by ultrasonic irradiation promotes the bulk segregate of generated charges. Benefiting from above two aspect effects, the overall separation of generated charges can be effectively achieved, leading to outstanding piezo-photocatalytic degradation activity of Bi2S3/BiOBr composite.

Density functional theory study on vanadium selective leaching separation from iron in stone coal via Fe2O3 (001) surface passivation

When vanadium is extracted from stone coal, iron impurities readily precipitate and reduce the purity of the vanadium product. Thus, separating vanadium from iron impurities at source is essential. The mechanism of surface passivation of Fe2O3 (001) for the selective leaching separation of vanadium from iron in stone coal was established in the present work. Analysis of mineral phase transformation and microscopic morphology indicates that Fe2O3 in stone coal can undergo a reaction with HF and F-. Subsequently, the hematite surface was covered with FeF3 passivation layer, resulting in the inhibition of hematite dissolving reaction. The results of density functional theory (DFT) computations demonstrate that the HF and F- can reform the Fe2O3 (001) surface via sedimentary behavior at mineral interface, and the adsorption energy can be down to -99.93kJ/mol for the F- adsorption configuration. During sulfuric acid leaching with CaF2 as an aiding agent, the transfer of electrons from Fe atoms to F atoms can weaken the stable Fe-F bonds and decrease the reactive activation of Fe atoms in Fe2O3. This study demonstrates the separation of vanadium from iron by means of hematite passivation in the attendance of fluoride at the atomic level of analysis.

Fabrication, Structural, DFT, Biological and Molecular Docking Studies of Fe(III), Ni(II), and Cu(II) Complexes Based on Schiff-base derived from benzene-1,4-diamine and 2-hydroxy-1-naphthaldehyde

This study presents the design & comprehensive characterization of three novel metal complexes derived from a Schiff base compound (H2PDN) synthesized from benzene-1,4-diamine and 2-hydroxy-1-naphthaldehyde, coordinated with Fe (III) (FePDN), Ni (II) (NiPDN), & Cu (II) (CuPDN). Structures of both the H2PDN ligand & its metal complexes were proposed utilizing various analytical methods, having elemental analysis, ultraviolet-visible spectroscopy, mass spectrospcopy, infrared spectroscopy, magnetic properties, conductivity measurement, & thermal analysis. The obtained data revealed octahedral geometries for both FePDN and CuPDN complexes, denoted as [Fe2(PDN)(H2O)4(Cl)4] and [Cu2(PDN)(H2O)6(Cl)2], respectively, while the NiPDN complex exhibited a distorted tetrahedral structure, represented as [Ni2(PDN)(H2O)2(Cl)2]. Density functional theory (DFT) computations were employed to validate the molecular structures & explore quantum chemical parameters of both H2PDN & its metal complexes. The synthesized H₂PDN Schiff base and its metal complexes (FePDN, NiPDN, CuPDN) showcased significant antimicrobial, anti-inflammatory, and antioxidant activities. NiPDN exhibited the highest inhibition zone against P. aeruginosa (21.44±0.28 mm) and S. aureus (19.37±0.40 mm), while CuPDN showed strong inhibition against E. coli (18.42±0.13 mm). NiPDN demonstrated excellent antibacterial efficacy with a low MIC against B. cereus (21.00±0.98 μM), and CuPDN displayed potent anti-inflammatory (IC50: 121.65 μM) and antioxidant activity (IC50: 84.7±0.77 μM). These results indicate the therapeutic potential of the H₂PDN complexes. Molecular docking studies targeting specific proteins (2VF5 for Escherichia coli, 3CKU for Aspergillus flavus, 5IKT for Human Cyclooxygenase-2, & 5IJT for human peroxiredoxin 2) were performed to assess the binding affinities & interactions of H2PDN & its metal complexes. The results propose promising potential for the application of H2PDN and its metal complexes as novel therapeutic agents with diverse biological activities.

Transition metals tailoring of phosphorus-doped gallium nitride nanotubes as sensors for N-butenyl homoserine lactone (BHL): A computational study

This investigation is focused on the impact of transition metals (Ag, Au, and Cu) encapsulations of phosphorus-doped gallium nitride nanotubes (P@GaNNTs) to achieve precise detection and sensing of N-Butenyl homoserine lactone (BHL), which is a biomarker for urinary tract infection, within the framework of density functional theory (DFT) computation at the B3LYP-D3(BJ)/def2SVP method. Adsorption studies unveil the adsorption energies for BHL detection across the systems, with BHL_Cu_P@GaNNT displaying the most favorable adsorption energy of −1.79247 eV and BSSE correction (−1.7685 eV). Additionally, sensor mechanisms are elucidated through Fermi energy level (EFL) calculations, revealing distinct values of 4.748, 4.242, 5.052, and 3.864 for BHL_Ag_P@GaNNT, BHL_Au_P@GaNNT, BHL_Cu_P@GaNNT, and BHL_P@GaNNT, respectively. These values signify variances in charge transfer dynamics upon BHL interaction. In essence, this study lays the foundation for the development of highly efficient biosensors with exceptional biomarker detection capabilities, particularly in the context of urinary tract infections (UTIs). It opens new avenues in the realm of biosensing technology, promising innovative solutions for healthcare and diagnostics.

One-step synthesis of magnetic catalysts containing Mn3O4-Fe3O4 from manganese slag for degradation of enrofloxacin by activation of peroxymonosulfate

Landfill disposal of manganese slag is a significant environmental concern on both local and global levels. Using manganese slag to synthesis catalysts to degrade organic pollutants in wastewater is a promising pathway for the solid waste treatment. Here, we propose a simple method to prepare magnetic catalysts containing Mn3O4-Fe3O4 (MMF) using manganese slag as raw materials. The MMF exhibits excellent degradation performance for enrofloxacin (ENR) with 97 % removal efficiency within 30 min and can be rapidly isolated from wastewater by magnet. Electron paramagnetic resonance (EPR) and quenching experiments demonstrated that 1O2 produced by the non-radical pathway is the principal active substance for ENR degradation. X-ray photoelectron spectroscopy (XPS) and density-functional theory (DFT) calculations indicate that Mn and Fe in MMF provide electrons for PMS activation and that the presence of Fe promotes the activation of the PMS and the cycling of Mn. This work paves the way for developing magnetic catalysts from manganese slag for the treatment of organic pollutants via advanced oxidation process.

Composition-optimized NiGa-LDH on MOF-derived and cobalt-nanoparticles-embedded carbon flakes for enhanced potassium-ion storage

Layered double hydroxides (LDHs), renowned for their distinct nanostructures, efficient ion channels, and high specific capacitance, are promising electrode materials for supercapacitors (SCs). However, commercial applications remain limited due to constraints in the rate capabilities and cycling. The synergistic effects of the composites can be leveraged by pairing LDHs with carbon materials to enhance the conductivity for better SC characteristics. Herein, flaky Zeolitic Imidazolate Framework(ZIF)-67 is deposited on carbon cloth and calcined to produce the MOF-derived composite of carbon nanosheet-embedded nano-cobalt particles (CPEC) on the surface of the carbon cloth. Afterward, NiGa-LDH with a controllable Ni to Ga ratio is synthesized on the CPEC to form a flower-like hierarchical nanostructure NiGa-LDH/CPEC@CC. Co nanoparticles act as nucleation sites for cohesive formation within the carbon cloth framework. Ni2Ga1-LDH/CPEC@CC has the best properties, such as a specific capacitance of 729.6F g−1 at 1 mA cm−2 and 97.3 % capacitance retention at 2 mA cm−2. The asymmetric supercapacitor (ASC) consisting of Ni2Ga1-LDH/CPEC@CC//AC has an excellent energy density of 83.96 Wh kg−1 with a power density of 80 W kg−1. Density-functional theory (DFT) calculations of Ni2Ga1-LDH/CPEC@CC affirm a potassium ion adsorption energy of −2.127 eV and density of state (DOS) near the Fermi level. The study imparts theoretical and technical knowledge about the design of complex nanostructures from MOF precursors.

DFT and Monte Carlo simulation studies of potential corrosion inhibition properties of some basic heterocyclic compounds

ABSTRACT This study utilises a combination of density functional theory (DFT) approach, 6-31G (d, p) basis set, and Monte Carlo (MC) simulations. The goal is to understand the relationship between the structure and properties of heterocyclic inhibitors and how they interact with Fe (110) surfaces. Furan, pyrrole, thiophene, pyridine, pyridazine, pyrimidine, indole, benzofuran, carbazole, quinolone, isoquinoline, and imidazole are the chemicals that were looked at in this study. The DFT calculations provide important insights into various properties of the inhibitors, such as molecular structure, dipole moments, electrostatic potential maps, Reduced Density Gradient (RDG), UV spectroscopy, and thermal characteristics. Carbazole has the smallest energy difference (4.789 eV) and the highest softness (0.209 eV−1), It also has the most chemical activity, Furthermore, the Monte Carlo models demonstrate that these derivatives have favourable adsorption energies on the Fe (110) surface. Among them, carbazole shows significant inhibitory potential. The study confirms that the carbazole compound with the biggest negative adsorption energy (−95.495) actually has the smallest energy difference and fits with the MC simulation for adsorption on Fe (110) when it is not charged. Carbazole has much stronger adsorption than oxazole, showing how the structure of a molecule affects how well an inhibitor works.

Enhanced single-atom cobalt layer in MAX phase for biomass electrooxidation integrated with hydrogen evolution

MAX phases have attracted considerable interest due to their structural diversities and potential applications. More than 150 MAX phases have been synthesized, especially expanding the range of A-site atoms from traditional main group elements to subgroup elements with outer layer d electronic structure. However, the functional applications for MAX phases remain somewhat limited. The A-site elements in MAX phases can amplify their inherent properties, transforming primary structural materials into multifunctional materials. As highly catalytic elements, introducing cobalt into the A-site of MAX phases can reveal surprising catalytic activities. Hence, the MAX phase with single-atom-thick cobalt layers was synthesized via an A-site alloying strategy in this work. The obtained V2(Sn2/3Co1/3)C MAX phase demonstrates efficient electrocatalysis in 5-hydroxymethylfurfural (HMF) oxidation reaction along with hydrogen evolution reaction (HER). In-situ electrochemical studies discover that HMF can prevent the self-reconstruction of MAX phase and oxygen evolution reaction (OER). The overall reaction reaches 94.4 % yield to 2,5-furandicarboxylic acid (FDCA) at 1.60 V. Density functional theory calculations suggest that the Co-Sn bimetallic synergy in the A-site promotes the reaction. This groundbreaking investigation into using MAX phases for biomass upgrading highlights their potential in green chemistry and beyond.