Favorable Adsorption Sites Research Articles

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.

Dataset for carbon dioxide adsorption on lizardite

This paper presents data on the adsorption of CO2 on the (001) and (00 ) surface lizardite. The data were obtained from calculations using the density functional theory (DFT) method implemented in the CASTEP software package. The calculations were performed using the plane wave basis set and the Perdew-Burke-Ernzerhof (PBE) exchange-correlation functional. A semi-empirical Grimme D2 correction was used to correctly account for dispersion interactions, which play an important role in physical adsorption processes. The data include optimized geometry and electronic properties of equilibrium states of adsorbed CO2 on (001) and (00 ) lizardite surfaces. They contain the most energetically favorable adsorption sites and estimates of the interaction strength between the adsorbate and adsorbent. The analysis of the electronic structure includes calculations of charge distribution, density of states (DOS), and visualizations of electron density difference isosurfaces. These data provide detailed insights into the redistribution of electron density during adsorption and the nature of the bonds formed. All data, including optimized crystal structures, electronic properties, and calculation results, are available in formats that can be read by commonly available text editors and specialized atomic structure visualization and analysis software. The presented dataset can serve as a foundation for further studies on the interactions of various molecules with the lizardite surface.

Small‐Molecule Polycyclic Aromatic Hydrocarbons as Exceptional Long‐Cycle‐Life Li‐Ion Battery Anode Materials

The growing demand for cost‐effective and sustainable energy‐storage solutions has spurred interest in novel anode materials for lithium‐ion batteries (LIBs). In this study, the potential of small‐molecule polycyclic aromatic hydrocarbons (SMPAHs) as promising candidates for LIB anodes is explored. Through a comprehensive experimental approach involving electrode fabrication, material characterization, and electrochemical testing, the electrochemical performance of SMPAHs, including naphthalene, biphenyl, 9,9‐dimethylfluorene, phenanthrene, p‐terphenyl, and pyrene (Py), is thoroughly investigated. In the results, the impressive cycle stability, high specific capacity, and excellent rate capability of the SMPAH electrode are revealed. Additionally, a direct contact prelithiation strategy is implemented to enhance the initial Coulombic efficiency (ICE) of SMPAH anodes, yielding significant improvements in the ICE and cycle stability. Computational simulations provide valuable insights into the electrochemical behavior and lithium‐storage mechanisms of SMPAHs, confirming their potential as effective anode materials. The simulations reveal favorable lithium adsorption sites, the predominant storage mechanisms, and the dissolution mechanism of Py through computational calculations. Overall, in this study, the promise of SMPAHs is highlighted as sustainable anode materials for LIBs, advancing energy‐storage technologies toward a greener future.

DFT study of lithium adsorption on silicon quantum dots for battery applications

Understanding lithium (Li) adsorption in silicon quantum dots (SiQDs) is crucial for optimizing Li-ion battery (LIB) anode materials. We systematically investigated Li adsorption in ten hydrogenated SiQDs (Si10H16, Si14H20, Si18H24, Si22H28, Si26H30, Si30H34, Si35H36, Si39H40, Si44H42, and Si48H46) across five adsorption sites (bridge(B), on-top(T), hollow-tetrahedral inner(Tdinner), hollow-tetrahedral surface(Tdsurface), and hollow-hexagonal(Hex)), utilizing density functional theory (DFT) with the M06–2X hybrid functional and 6-31G+(d) basis set. Findings identify Tdinner as the most favorable adsorption site, with a binding energy (Ebind) of 0.80–1.00 eV, dependent on SiQD size. The adsorption site exerts a more pronounced impact on Ebind than the cluster size. Multiple adsorptions in SiQDs show increased Ebind per Li atom with Li atom number. Molecular volume changes, independent of Li atom number but site-dependent, exhibit a maximum of 2.51 %. SiQD energy gap, influencing conductivity, varies with size, larger SiQDs being more conductive, especially with Li adsorption. Conclusively, our study recommends large-sized SiQDs as optimal LIB anode materials, offering high capacity, minimal volume expansion, and reasonable conductivity. This research addresses a theoretical gap, illuminating the impact of Li adsorption on SiQD molecular volumes and electronic structures, aiding in the design of enhanced capacity silicon anodes for LIB.

Lithium cation-doped tungsten oxide as a bidirectional nanocatalyst for lithium-sulfur batteries with high areal capacity

Lithium-sulfur (Li-S) batteries are promising for high energy-storage applications but suffer from sluggish conversion reaction kinetics and substantial lithium sulfide (Li2S) oxidation barrier, especially under high sulfur loadings. Here, we report a Li cation-doped tungsten oxide (LixWOx) electrocatalyst that efficiently accelerates the S↔Li2S interconversion kinetics. The incorporation of Li dopants into WOx cationic vacancies enables bidirectional electrocatalytic activity for both polysulfide reduction and Li2S oxidation, along with enhanced Li+ diffusion. In conjunction with theoretical calculations, it is discovered that the improved electrocatalytic activity originates from the Li dopant-induced geometric and electronic structural optimization of the LixWOx, which promotes the anchoring of sulfur species at favourable adsorption sites while facilitating the charge transfer kinetics. Consequently, Li-S cells with the LixWOx bidirectional electrocatalyst show stable cycling performance and high sulfur utilization under high sulfur loadings. Our approach provides insights into cation engineering as an effective electrocatalyst design strategy for advancing high-performance Li-S batteries.

Hydrogen storage in M(BDC)(TED)0.5 metal-organic framework: physical insights and capacities.

Finding renewable energy sources to replace fossil energy has been an essential demand in recent years. Hydrogen gas has been becoming a research hotspot for its clean and free-carbon energy. However, hydrogen storage technology is challenging for mobile and automotive applications. Metal-organic frameworks (MOFs) have emerged as one of the most advanced materials for hydrogen storage due to their exceptionally high surface area, ultra-large and tuneable pore size. Recently, computer simulations allowed the designing of new MOF structures with significant hydrogen storage capacity. However, no studies are available to elucidate the hydrogen storage in M(BDC)(TED)0.5, where M = metal, BDC = 1,4-benzene dicarboxylate, and TED = triethylenediamine. In this report, we used van der Waals-dispersion corrected density functional theory and grand canonical Monte Carlo methods to explore the electronic structure properties, adsorption energies, and gravimetric and volumetric hydrogen loadings in M(BDC)(TED)0.5 (M = Mg, V, Co, Ni, and Cu). Our results showed that the most favourable adsorption site of H2 in M(BDC)(TED)0.5 is the metal cluster-TED intersection region, in which Ni offers the strongest binding strength with the adsorption energy of -16.9 kJ mol-1. Besides, the H2@M(BDC)(TED)0.5 interaction is physisorption, which mainly stems from the contribution of the d orbitals of the metal atoms for M = Ni, V, Cu, and Co and the p orbitals of the O, C, N atoms for M = Mg interacting with the σ* state of the adsorbed hydrogen molecule. Noticeably, the alkaline-earth metal Mg strongly enhanced the specific surface area and pore size of the M(BDC)(TED)0.5 MOF, leading to an enormous increase in hydrogen storage with the highest absolute (excess) gravimetric and volumetric uptakes of 1.05 (0.36) wt% and 7.47 (2.59) g L-1 at 298 K and 7.42 (5.80) wt% and 52.77 (41.26) g L-1 at 77 K, respectively. The results are comparable to the other MOFs found in the literature.

Directed growth of quinacridone chains on the vicinal Ag(35 1 1) surface.

The formation of self-assembled domains and chains of monomolecular width of quinacridone (QA) on the vicinal Ag(35 1 1) surface was investigated by scanning tunneling microscopy and low-energy electron diffraction. The focus was on the influence of the steps on the QA structures and their preferential azimuthal orientations with the aim of achieving a selective orientation. After deposition at a sample temperature of 300 K, QA forms the same kind of molecular chains as on the nominally flat Ag(100) surface because of strong intermolecular hydrogen bonds, which we reported in a previous publication [Humberg, N.; Bretel, R.; Eslam, A.; Le Moal, E.; Sokolowski, M. J. Phys. Chem. C 2020, 124, 24861-24873]. The vicinal surface leads to one additional chain orientation, which is parallel to the Ag step edges. However, most chains nucleate on the Ag terraces between steps with four distinct azimuthal orientations that are identical to those on Ag(100), and which are determined by the interactions with the (100) surface. At 300 K, the chains grow across the Ag steps, which do not break the azimuthal chain orientations. In contrast, during the deposition at sample temperatures of 400 and 500 K, the nucleation of the chains takes place at the Ag step edges. Hence, these have a strong influence on the azimuthal orientation of the molecules, resulting in a preferential growth of the chains in two of the four azimuthal orientations. We explain this by the adaptation of favorable adsorption sites, which involve the replacement of Ag atoms by QA molecules with specific azimuthal orientations at the step edges.

Effect of doped heteroatom on monolayer SnSe2 adsorption of Na

Based on the first principles, we have calculated the influence of B, Br, and N atom doping on the adsorption properties and optoelectronic properties of monolayer SnSe2 adsorbed Na. The calculations show that vacancy is the most favorable adsorption site for the Na atom. Among the three doping systems, the B-doped system has the best adsorption energy and height and Na’s adsorption capacity. After the adsorption of the Na atom by intrinsic SnSe2, the system behaves from a semiconductor to a metal nature. Doping Br atom increases the adsorption system’s Fermi energy level, the conduction band’s overall energy increases and the electrical conductivity is enhanced. Doping B and N atoms change the adsorption system from metallic to p-type semiconductor properties. The system’s adsorption performance, electrical conductivity, and energy band tunability are improved. Due to the electrostatic repulsion between Na atoms, the adsorption energy of the system shows an increasing trend with the increase in the number of adsorbed Na atoms on the surface. The maximum specific capacity of the surface of the doped system is 373 mAhg−1, and the system has high storage capacity. Optical property calculations show that the static refractive index of the Br-doped adsorption system is maximum. The static refractive index of the doped adsorption system is minimal. Doping makes the system’s energy loss smaller, complex conductivity decreases, intermolecular interactions decrease, and the adsorption system becomes more stable.

Laser-assisted preparation of vertically aligned reduced graphene oxide/tannic acid arrays for flexible aqueous zinc-ion hybrid capacitors

Aqueous zinc-ion hybrid capacitors (AZHCs) are considered an encouraging energy storage candidate owing to their promising environmental benignity and electrochemical performance. To give full play to the advantages of AZHCs, vertically aligned reduced graphene oxide/tannic acid (V-rGO/TA) arrays are constructed on the laser-pretreated graphite paper (LGP) as flexible carbon-based cathodes (V-rGO/TA/LGP) for AZHCs by a facile laser reduction method. The vertical structure of rGO exhibits abundant physical adsorption sites and ion/electron transfer channels, and the residual oxygen-containing groups of rGO provide favored chemical adsorption sites, which can enhance Zn2+ ion storage. In addition, the TA molecules contribute extra capacity by reversible redox reaction (phenol-quinone transition), further improving the electrochemical performance of the electrode. Consequently, the assembled quasi-solid-state AZHC based on the optimized V-rGO/TA/LGP cathode possesses a high specific capacity of 136.6 µAh cm−2 and a maximum energy density of 109.3 μWh cm−2. In addition, the device exhibits good flexibility with a capacity retention of 97.0 % even after 3000 bending cycles. This design strategy opens up a new approach to construct a vertically aligned carbon material for achieving high-performance flexible AZHCs and realizing their practical applications.

In-situ converting CoO@Co/RGO into Co/Co(OH)2/RGO for improved dye-sensitized photocatalytic H2 evolution

It is of huge challenge to develop stable and efficient non-metal based cocatalysts for photocatalytic hydrogen evolution reaction (HER) via dye sensitization. Herein, we demonstrate a composite featuring Co(OH)2 nanosheets embedded with metal Co nanocrystallines on reduced graphene oxide (Co/Co(OH)2/RGO) as a durable cocatalyst, which is obtained from the CoO@Co/RGO composite in dye-sensitized photocatalytic HER process via the dissolution-precipitation reaction of Co element. The large CoO@Co nanoparticles (∼43 nm in diameter) are converted to thin Co(OH)2 nanosheets, and tiny Co nanocrystalllines are exposed on the surface. As a fresh cocatalyst, Co/Co(OH)2/RGO is endowed with favorable adsorption sites of both hydrogen and hydroxyl. Such a phase and structure transformation leads to the high photocatalytic activity (136.1 μmol) of Co/Co(OH)2/RGO cocatalyst via dye sensitization, which is 3.7 times as much as that of pristine CoO@Co/RGO (36.7 μmol). The improved HER performance should be highly related to the more effective interfacial electron transfer ability, as reflected by transient absorption decays, and photocurrent test. Moreover, the Co/Co(OH)2/RGO cocatalyst shows a remarkable stability of photocatalytic H2 evolution, as well as the structural and phase stability. This work provides a novel route to develop highly dispersive and efficient non-noble metal based cocatalysts, and a new vision to understand the dynamic structure–activity relationship of the cocatalysts.

Detecting Hachimoji DNA: An Eight-Building-Block Genetic System with MoS2 and Janus MoSSe Monolayers.

In the pursuit of personalized medicine, the development of efficient, cost-effective, and reliable DNA sequencing technology is crucial. Nanotechnology, particularly the exploration of two-dimensional materials, has opened different avenues for DNA nucleobase detection, owing to their impressive surface-to-volume ratio. This study employs density functional theory with van der Waals corrections to methodically scrutinize the adsorption behavior and electronic band structure properties of a DNA system composed of eight hachimoji nucleotide letters adsorbed on both MoS2 and MoSSe monolayers. Through a comprehensive conformational search, we pinpoint the most favorable adsorption sites, quantifying their adsorption energies and charge transfer properties. The analysis of electronic band structure unveils the emergence of flat bands in close proximity to the Fermi level post-adsorption, a departure from the pristine MoS2 and MoSSe monolayers. Furthermore, leveraging the nonequilibrium Green's function approach, we compute the current-voltage characteristics, providing valuable insights into the electronic transport properties of the system. All hachimoji bases exhibit physisorption with a horizontal orientation on both monolayers. Notably, base G demonstrates high sensitivity on both substrates. The obtained current-voltage (I-V) characteristics, both without and with base adsorption on MoS2 and the Se side of MoSSe, affirm excellent sensing performance. This research significantly advances our understanding of potential DNA sensing platforms and their electronic characteristics, thereby propelling the endeavor for personalized medicine through enhanced DNA sequencing technologies.

A vinyl-pedant triazine-based covalent organic framework for efficient C3H6/C2H4 separation

The separation of propylene (C3H6) and ethylene (C2H4) during the methanol-to-olefin (MTO) process is crucial yet challenging. Herein, we report a covalent organic framework (TzDva) featuring favorable nitrogen adsorption sites and vinyl modification for the capture of C2H4 from C3H6/C2H4 mixtures. TzDva exhibits enhanced crystallinity and porosity as well as reduced pore size compared to its vinyl-free counterpart (TzPA), as revealed through comprehensive characterization. The excellent performance of TzDva for C3H6/C2H4 separation combined with its excellent recyclability was confirmed by both static adsorption and dynamic breakthrough experiments. Particularly, it exhibits a C2H4 productivity of 4.29 mmol g−1 at 298 K with C3H6/C2H4 (10/90) mixture. With decreasing temperature to 273 K, the performance can be further enhanced. Theoretical calculations and in-situ infrared analysis suggested that the remarkable selectivity of TzDva towards C3H6 stems from its favorable pore environment, which facilitates a greater number of interactions with C3H6 compared to C2H4 guests. These results underpinned the effective separation of gas mixtures relevant to the MTO process.

SERS-Based Sensor Using Subnanometric Copper-Silver Mixed Clusters Ag(8-n)Cun (n = 0-8) for Pyridine: A DFT Study.

Surface-enhanced Raman spectroscopy (SERS) is a powerful Raman technique that provides high selectivity and sensitivity in analyzing the intermolecular interaction of a target compound adsorbed on the surface of a noble nanomaterial, i.e., silver, gold, or copper. Although copper presents a better SERS enhancement than gold and silver, its oxidation in the air is much easier than that of gold and silver. A mixed material between these metals may potentially improve the SERS signal enhancement in this context. In this work, we evaluated the SERS spectra of pyridine (Py) adsorbed on the copper-silver mixed clusters Ag(8-n)Cun (n = 0-8) using density functional theory (DFT) at the PBE functional. The cc-pVDZ-PP basis set was chosen for Ag and Cu, while the cc-pVDZ basis set was used for C, N, and H atoms. Geometrical and electronic structures of the mixed clusters and the Py adsorption configuration on these clusters were computed. The calculated SERS spectra then revealed the influence of the Ag/Cu mixing ratio on the SERS enhancement. As a result, the substituted copper atoms on the silver cluster turned out to be favorable adsorption sites for Py. Interestingly, when the number of Cu atoms increased from n = 0 (pure Ag8 cluster) to n = 5 (Ag3Cu5 cluster), the ring stretching peak (1590 cm-1) of Py significantly increased from 20 to 120 au and then saturated around this value despite increasing the Cu atom number to 8 (pure Cu8 cluster). This observation was extended for other ligands such as pyrazine and 3H-pyrrole. TD-DFT was then employed to clarify the chemical enhancement mechanism. The results obtained hopefully provide helpful information for the design of analytical sensors with lower costs.

A First‐Principles Investigation of Monolayer MoS2 Doped with Mn and V as an Excellent NO2 Sensor with High Selectivity

This article conducts a comprehensive investigation into the adsorption properties of both pristine MoS2 monolayers and those doped with Mn and V, wherein these dopants replace Mo atoms. By the first‐principles calculations, the research reveals a noteworthy reduction in the adsorption energy of NO2 on Mn‐doped and V‐doped MoS2 monolayers compared to pure MoS2 monolayers. Specifically, at the most favorable adsorption site, the adsorption energy decreases from −5.83 to 5.908 eV for Mn‐doped MoS2 and from −5.58 to −6.17 eV for V‐doped MoS2. Furthermore, computations of the band structure, work function, and charge density difference highlight a significant degree of charge transfer and coexistence of electrons within these systems. Additionally, post‐adsorption of NO2 molecules, a distinct shift in the density of states (DOS) toward lower energy states is observed at the adsorption sites of both MoS2/Mn and MoS2/V monolayers, underscoring their exceptional sensitivity in detecting NO2. In summary, these results demonstrate the substantial potential of Mn‐doped and V‐doped MoS2 monolayers as highly sensitive materials for NO2 detection. Their lower adsorption energies and noteworthy shifts in DOS following NO2 adsorption enhance their capabilities as NO2 sensors.

Designing activated carbon and porous carbon nanofibers for insight into their differences in adsorption affinity mechanisms of VOCs

The adsorption technology has been considered as an effective and economical strategy to control volatile organic compounds (VOCs) through various types of porous materials. As two potential porous materials, activated carbon and carbon nanofibers were synthesized as VOCs adsorbents. In order to investigate the difference in the adsorption of VOCs between activated carbon and carbon nanofibers, the specific surface area, pore structure and chemical functional groups of VOCs adsorbent were analyzed. In particular, the carbon nanofibers (CNF) activated at 800 ℃ showed an excellent specific surface area (2524 m2·g−1), abundant pores (1.66 mL·g−1), and rich functional groups (N: 8.29 at%). Meanwhile, the carbon nanofibers had a better adsorption performance for acetone (1069.82 mg·g−1) and toluene (427.72 mg·g−1) than activated carbon materials. Furthermore, the theoretical calculations were conducted to reveal the mechanism of favorable adsorption on the CNFs. The theoretical adsorption energies of CNF are −31.9 kJ·mol−1 (acetone) and −67.5 kJ·mol−1 (toluene), respectively, which have more favorable adsorption sites and stronger charge redistribution than activated carbon. This research guided the approach to obtain the porous carbon nanofibers and provided the evidence for CNFs (curved carbon) exhibiting a better adsorption ability to VOCs.

Microalgae derived honeycomb structured mesoporous diatom biosilica for adsorption of malachite green: Process optimization and modeling

The present study investigated the removal of malachite green dye from aquifers by means of microalgae-derived mesoporous diatom biosilica. The various process variables (dye concentration, pH, and adsorbent dose) influencing the removal of the dye were optimized and their interactive effects on the removal efficiency were explored by response surface methodology. The pH of the solution (pH = 5.26) was found to be the most dominating among other tested variables. The Langmuir isotherm (R2 = 0.995) best fitted the equilibrium adsorption data with an adsorption capacity of 40.7 mg/g at 323 K and pseudo-second-order model (R2 = 0.983) best elucidated the rate of dye removal (10.6 mg/g). The underlying mechanism of adsorption was investigated by Weber-Morris and Boyd models and results revealed that the film diffusion governed the overall adsorption process. The theoretical investigations on the dye structure using DFT-based chemical reactivity descriptors indicated that malachite green cations are electrophilic, reactive and possess the ability to accept electrons, and are strongly adsorbed on the surface of diatom biosilica. Also, the Fukui function analysis proposed the favorable adsorption sites available on the adsorbent surface.

Adsorption and reversible detection of toxic halogens gases at room temperature by two-dimensional Al2SSe for occupational sustainability

Current treatment for inhalational halogens poisoning involves providing supportive care, which includes administering humidified oxygen and managing the airway. Since toxic effects of halogens cannot be reversed, sensors with high sensitivity and good reversibility for detecting the relatively lower concentration yet noxious halogens becomes particularly significant and enticing. Herein, the structural and optoelectronic properties of toxic F2 and Cl2 gas molecules adsorbed on highly stable Al2SSe monolayer have been systematically studied by means of first-principles calculations based on density functional theory (DFT). Favorable adsorption sites of said molecules on Al2SSe were carefully examined. The relatively high, negative adsorption energy for F2 and Cl2 indicate that the adsorption process is exothermic and the molecules could be stably adsorbed on Al2SSe monolayer. This characteristic, combined with the substantial charge transfer (0.15–0.55 |e|), drastic change in work function, complete reversibility due to recovery time in 10−1 s scale and distinct optical response, render Al2SSe monolayer a viable option for utilization as either surface work functions transistor or optical chemical resistor for detecting these gases. Pearson correlation coefficient (PCC) analysis of theoretical recovery time and response value indicates that band gap change and electron transfer are the primary influencing factors. Selectivity analysis reveals that common compound forms of halogens and atmospheric molecules such as HF, HCl, N2, O2, H2 and H2O are either physically adsorbed or inert with extremely low adsorption energies on Al2SSe, prompting high F2 and Cl2 selectivity. These outcomes acclaim the exciting prospects of developing Al2SSe monolayer for specific, occupational related ultrahigh-sensitivity F2 and Cl2 sensing nanodevices.

Unraveling the mechanism of modulating external electric fields for regulating nitrogen fixation and activation on three-atom metal clusters

Efficient N2 fixation and activation under mild conditions are critical for green ammonia synthesis. Coupling external electric fields with three-atom transition metal clusters is a promising approach to realizing this vision. Herein, we report an effective strategy by modulating external electric fields to regulate the adsorption and activation of N2 on Sc3. The mechanism is further elucidated through DFT calculations. The most favorable adsorption site for N2 is the hollow site of Sc3. Although external electric fields inhibit the adsorption process of N2 on Sc3, the adsorbing performance of Sc3 is still very superior. Positive fields promote the activation and polarization of the adsorbed dinitrogen on the three-atom cluster, and negative fields have the opposite effect. The synergistic effect of positive/negative electric fields and Sc3 regulates the charge distribution of NN* in different ways. Furthermore, the d-band center (relative to the Fermi level), which determines the adsorption strength of N2, is affected by both positive and negative fields, resulting from the electron donation and back-donation mechanism between the NN* and the Sc3. This work provides guidelines for designing surface-anchored three-atom clusters with superior ammonia synthesis performance under electric fields in the future.

Unveiling the potential of a BCN-biphenylene monolayer as a high-performance anode material for alkali metal ion batteries: a first-principles study.

Inspired by a freshly synthesized two-dimensional biphenylene carbon network, which features a captivating combination of hexagonal, square, and octagonal rings, we explored a similar biphenylene network composed of boron, carbon, and nitrogen (bpn-BCN) using first-principles calculations. There are six possible phases of borocarbonitrides, which are isoelectronic to biphenylene carbon networks with a stoichiometric ratio of 1 : 1 : 1 for boron (B), carbon (C), and nitrogen (N) atoms. All possible isoelectronic structures of the BCN combination of biphenylene networks are found to be stable, according to first-principles calculations. However, the geometry has a relatively large number of robust C-C and B-N bonds and strong partially ionic-covalent B-C and C-N bonds inside these bpn-BCN monolayers are effectively more stable. Furthermore, we employed first-principles calculations to investigate the electrochemical properties of the most stable geometry of BCN biphenylene as a potential anode material for alkali metal (AM) ion batteries. A global search has been made to find the most favourable alkali metal ion adsorption sites. The biphenylene monolayer has octagonal, square, and hexagonal motifs with different adsorption strengths. Furthermore, the partially ionic bond of B-N (due to the electronegativity difference) also supports the alkali metal ions for adsorption. The electronic properties of the stable phase of bpn-BCN reveal its narrow bandgap semiconductor nature. The ion diffusion calculations show a low activation barrier for Li, Na, and K of 0.65 eV, 0.26 eV, and 0.23 eV, respectively, indicating a fast charge/discharge rate. Furthermore, the theoretical capacities of the BCN biphenylene monolayer for Li (1057.33 mA h g-1), Na (647.27 mA h g-1), and K (465.98 mA h g-1) are found to be greater than those of commercial graphite. The average open-circuit voltage for AM decreases with increasing metal ion concentrations. It falls within a reasonable range of 0.34-1.89 V. Our results show that the BCN biphenylene monolayer could be a promising anode material in alkali metal ion rechargeable batteries.

Bismuthene as a novel anode material of magnesium/zinc ion batteries with high capacity and stability: a DFT calculation.

In our research, we utilize density functional theory (DFT) to explore the properties of magnesium and zinc atoms adsorbed on bismuthene. Our findings indicate that the hollow site is the most favorable adsorption site for Mg and Zn atoms on bismuthene. The results indicate that Mg and Zn adsorption on the bismuthene surface results in significantly high conductivity, with notable adsorption energies of -3.38 eV for Mg and -3.91 eV for Zn. The bismuthene structure can adsorb 9 Mg and 18 Zn atoms with negative average adsorption energy. These findings suggest excellent stability of bismuthene during the adsorption of magnesium and zinc. Notably, we propose theoretical storage capacities of 2308 mA h g-1 for magnesium-ion batteries (MgIBs) and 4616 mA h g-1 for zinc-ion batteries (ZnIBs), while maintaining structural stability during the adsorption of these metal ions. The observed average open-circuit voltages for bismuthene are 0.01 V for Mg and 0.03 V for Zn, with the material retaining its metallic properties throughout the adsorption process. Furthermore, the calculated diffusion barriers for Mg and Zn are 0.1 eV and 0.21 eV, respectively. Our findings like storage capacity, diffusion energies, and low OCV surpass those of most studied two-dimensional materials, positioning bismuthene as a promising anode material for metal-ion rechargeable batteries.