D-orbital Electrons Research Articles

Influence mechanism of divalent metals in the laminates of M2+Al-layered double hydroxides on peroxymonosulfate activation reaction pathway: Radical vs nonradical

Radical and nonradical reaction pathways have been commonly validated in peroxymonosulfate (PMS) based advanced oxidation progresses (AOPs) using layered double hydroxides (LDHs) as catalysts, but achieving efficient and selective degradation of organic pollutants remains challenging due to the unclear regulatory mechanism of laminate M2+ in PMS activation. Here, the d-orbital electrons configuration of M2+ was found to influence the degree of overlap between M−OH and O of PMS, which results in the selective dissociation of PMS to form reactive oxygen species (ROS) or achieve electron transfer pathway. Further analysis revealed that Co(II, 3d7) and Ni(II, 3d8) with filled 3d orbital electrons can serve as electron donors for PMS, leading to the cleavage of O–O bond and the efficient generation of radical-based ROS. In contrast, Mg(II, 3d0) with unfilled 3d orbital electrons and Zn(II, 3d10) with full filled 3d orbital electrons tend to act as electron shuttles, and the outermost orbitals substantially overlap with the O of PMS to form metastable complexes. Consequently, MgAl-LDH interacts with PMS to selectively degrade quinolones as electron donor through electron transfer pathway, and its performance was not inhibited by common anions and organic matter in actual water. The above results provide a basis for optimizing the design of LDH-based catalysts according to the type of laminate M2+ to achieve high selectivity and efficiency of PMS-AOPs in water purification applications.

2D MXene nanosheet dispersed Mn, Ru NPs loaded Ti composite electrodes for electrocatalytic synergistic degradation of antibiotics in high-salt mariculture wastewater

In this study, a composite electrode based on etched TiO2 nanotube arrays and two-dimensional (2D) MXene nanosheets was successfully designed for efficient degradation of antibiotics in mariculture wastewater. The composite electrode effectively dispersed Mn and Ru nanoparticles (NPs) by introducing 2D MXene nanosheets as an intermediate layer, which significantly enhanced the catalytic performance. The bifunctional properties of Mn and Ru NPs in catalysis and the contribution of d-orbital electrons to the formation of metal‑hydrogen bonds were revealed in depth by analyzing the electron transfer mechanism at the electrodes. The experimental results demonstrated a synergistic catalytic effect between Mn and Ru bimetals and MXene, resulting in an effective increase in the degradation rate. Under the optimal conditions, the degradation rate of Tetracycline (TC) by Mn/Ru/MXene/Ti composite electrode could reach 90.69 % in 60 min. In addition, it still shows excellent stability after 45 days of air exposure, 10 cycling experiments, and 10,000 s of timed current testing. Mechanistic studies have demonstrated that anode hydroxyl radical (·OH), HClO, and cathode activated hydrogen atoms (H*) all play catalytic roles in the degradation process. The degradation pathways were analyzed using density-functional theory (DFT) calculations and liquid-liquid-mass spectrometry (LC-MS) techniques, with further experiments confirming that this degradation process effectively reduces the biotoxicity of intermediate products, improving the safety of wastewater discharge. Finally, we designed the reactor and calculated the energy consumption to verify the feasibility and economy of the system in practical applications. This research proposes a novel multi-metal co-catalysis and cathode and anode co-catalysis system for the efficient degradation of antibiotics in mariculture wastewater, with potential applications in the electrocatalytic degradation of antibiotics.

Manipulation of d-Orbital Electron Configurations in Nonplanar Fe-Based Electrocatalysts for Efficient Oxygen Reduction.

Manipulation of the spin state holds great promise to improve the electrochemical activity of transition metal-based catalysts. However, the underlying relationship between the nonplanar metal coordination environment and spin states remains to be explored. Herein, we report the precise regulation of nonplanar Fe atomic d-orbital energy level into an irregular tetrahedral crystal field configuration by introducing P atoms. With the increase of P coordination number, the spin magnetic moment decreases linearly from 3.8 μB to 0.2 μB, and the high spin content decreases linearly from 31% to 5%. Significantly, a volcanic curve between the spin states of Fe-based catalysts (Fe-NxPy) and oxygen reduction reaction (ORR) activity has been unequivocally established based on the thermodynamic results. Thus, the Fe-N3P1 catalyst with a 19% medium spin state experimentally exhibits the optimal reaction activity with a high half-wave potential of 0.92 V. These findings indicate that regulating electron spin moments through coordination engineering is a promising catalyst design strategy, providing important insights into spin catalysis.

A DFT theoretical prediction of new half-metallic ferromagnetism, mechanical stability, optoelectronic and thermoelectric properties of ZnCrO3 perovskites for spintronic applications

ZnCrO3 perovskites structural stability, optoelectronic, mechanical, along with thermoelectric properties, have all been to be described by calculations based on density functional theory (DFT). To determine the exchange correlation potential, the well-known generalized gradient approximation (GGA) and integration of the mBJ potential were used. The perovskite shows that this is in a cubic structure with Fm3m symmetry. Additionally, to check the stability, cohesive energy, structural optimization, and mechanical stability were requirements. This perovskite was found to be brittle, and their mechanical stability enhanced by the elastic constants. The perovskite has a half-metallic character, as evidenced by the spin-polarized electronic band profile, the behavior of the dielectric constant, and absorption coefficient in the spin-up and down channels. In this article, we also looked at magnetism and the origin of the half-metallic gap. The unpaired electrons in the split d-orbitals of the M-sited elements in the crystal field are responsible for the half-metallic as well as magnetic characteristics. Excellent spin polarization at the Fermi level encourages perovskite's possible use in spintronic technologies. Lastly, we computed the thermoelectric parameters within a chemical potential at various temperatures (300 K, 600, 900 K) to explore the potential application in spin electronic devices. Our finding shows that the ZnCrO3 alloy is exceptionally promising for the next generation of spintronics and thermoelectric devices at room and high temperatures.

Directionally charging d-orbital electron of Mo2C MXene via in-situ coupled MoSe2 nanosheets for exceptional photocatalytic H2 generation

Mo2C MXene as a promising noble-metal-free cocatalyst has attracted considerable attention in the domain of photocatalytic H2 evolution due to its unique 2D layered structure, outstanding metallic conductivity, and Pt-like d-band electronic structure. However, the plentiful −F terminal groups with high electronegativity of Mo2C MXene (referred as Mo2CFx) owing to the residue of F-containing etchants lead to strong interaction between active Mo sites and adsorbed atomic H (Mo-Had bond), thereby decreasing the H2-evolution activity of Mo2CFx. In this work, a directionally charging d-orbital electron strategy of Mo2CFx-MoSe2 heterojunction via increasing the antibonding-orbital occupancy state of Mo to weaken Mo-Had bond in Mo2CFx is presented for the enhanced H2-generation performance. Herein, the ultrathin MoSe2 nanosheets are first vertically grown on the Mo2CFx surface via an in-situ selenization route to form Mo2CFx-MoSe2 heterojunction, and subsequently combined with the TiO2 to prepare the TiO2/Mo2CFx-MoSe2 through an ultrasonic-assisted method. The H2-evolution activity test indicates that the optimal TiO2/Mo2CFx-MoSe2 photocatalyst possesses an exceptional H2-evolution rate (427.66 μmol h−1 g−1), which is 38.98 and 1.94 folds higher than that of the TiO2 and TiO2/Mo2CFx, respectively. The experimental data and density functional theory (DFT) calculations substantiate that the generation of Mo2CFx-MoSe2 heterojunction can weaken the Mo-Had bond by electron transfer from MoSe2 to Mo2CFx for charging d-orbital electrons, accordingly promoting the photocatalytic H2-evolution efficiency of TiO2. This study highlights the optimization of Mo-Had bond by constructing Mo2CFx-based heterojunction to realize high-efficient photocatalytic H2 evolution.

Phosphorus-doped cobalt oxide/cobalt sulfide heterostructure for enhanced oxygen evolution

Regulating the distribution of valence charges near the Fermi level and d-band center of metal atom active sites is crucial for developing highly efficient and stable catalysts for oxygen evolution reaction (OER), yet it remains a significant challenge. In this study, we prepared phosphorus-doped Co3O4/Co9S8 catalysts with a mesoporous nanorod morphology and Mott-Schottky heterojunction. Compared to Co3O4, Co9S8 and Co3O4/Co9S8, this catalyst exhibits enhanced OER properties with an overpotential of 156 mV at 10 mA cm−2, 380 mV at 50 mA cm−2, and 450 mV at 100 mA cm−2. Moreover, when a voltage of 2.0 V vs. RHE is applied, the current density reaches 350 mA cm−2. Density functional theory (DFT) calculations reveal that the coupling of Co3O4 and Co9S8 interfaces and phosphorus doping lead to the rearrangement of d-orbital electrons of Co atoms on the crystal plane, optimizing the d-band center. Crystal orbital Hamilton population (COHP) analysis shows that the partial anti-bonding state transitions into the unoccupied region, reducing the anti-bonding state and enhancing the bonding state, thus significantly improving the adsorption for the target intermediate (*OOH), resulting in higher intrinsic activity. This study demonstrates that the pathway of doping this heterojunction with P synergistically enhances the catalytic activity of this composite for OER in water splitting electrocatalysis.

Highly efficient flotation of ilmenite with a novel dithiocarbamate-hydroxamate collector

The pre-activation of lead nitrate has been extensively proved to be an effective technique in ilmenite flotation, and sodium oleate is the preferred collector. Realization the clean flotation of ilmenite is an important aspect to respond the green and low-carbon policy. In this work, a dithiocarbamate-hydroxamate collector OAHD was pioneeringly added into the direct flotation of ilmenite as an efficient collector. The micro-flotation performance found that OAHD realized an efficient flotation of ilmenite under low concentration of 1.0 × 10−5 mol/L under around pH 8.0, and the flotation recovery rate of ilmenite reached about 94.2%, which was about 35.8% higher than that of NaOL. The morphology of ilmenite observed by AFM probed the self-assemble adsorption behavior of OAHD on ilmenite surface. DFT (density functional theory) calculations suggested that both dithiocarbamate and hydroxamate groups are the chemical active centers and have strong electron acceptability of d-orbital electrons of Fe atoms at/on the interface of ilmenite. UV–Vis spectra demonstrated that dithiocarbamte and hydroxamate groups simultaneously has strong chemical reaction with Fe2+ ions. XPS analysis recommended that OAHD chemisorbed on ilmenite surface to produce the surface Fe(II)-OAHD complexes where the O,O-five membered ring of Fe(II)-hydroxamate compounds were formed.

Linker Mediated Electronic-State Manipulation of Conjugated Organic Polymers Enabling Highly Efficient Oxygen Reduction.

Conjugated polymers with tailorable composition and microarchitecture are propitious for modulating catalytic properties and deciphering inherent structure-performance relationships. Herein, we report a facile linker engineering strategy to manipulate the electronic states of metallophthalocyanine conjugated polymers and uncover the vital role of organic linkers in facilitating electrocatalytic oxygen reduction reaction (ORR). Specifically, a set of cobalt phthalocyanine conjugated polymers (CoPc-CPs) wrapped onto carbon nanotubes (denoted CNTs@CoPc-CPs) are judiciously crafted via in situ assembling square-planar cobalt tetraaminophthalocyanine (CoPc(NH2)4) with different linear aromatic dialdehyde-based organic linkers in the presence of CNTs. Intriguingly, upon varying the electronic characteristic of organic linkers from terephthalaldehyde (TA) to 2,5-thiophenedicarboxaldehyde (TDA) and then to thieno/thiophene-2,5-dicarboxaldehyde (bTDA), their corresponding CNTs@CoPc-CPs exhibit gradually improved electrocatalytic ORR performance. More importantly, theoretical calculations reveal that the charge transfer from CoPc units to electron-withdrawing linkers (i.e., TDA and bTDA) drives the delocalization of Co d-orbital electrons, thereby downshifting the Co d-band energy level. Accordingly, the active Co centers with more positive valence state exhibit optimized binding energy toward ORR-relevant intermediates and thus a balanced adsorption/desorption pathway that endows significant enhancement in electrocatalytic ORR. This work demonstrates a molecular-level engineering route for rationally designing efficient polymer catalysts and gaining insightful understanding of electrocatalytic mechanisms.

Modulating electronic structure of Fe site by adjacent Cu site through orbital coupling in Cu-Fe2O3 catalyst derived from Fenton sludge quenching

The incorporation of specific atoms into catalysts derived from Fenton sludge has the potential to regulate active site for promoting peroxymonosulfate (PMS) activation. Here, quenching technology was employed in this study to facilitate the production of a highly active Fe2O3-based catalyst from Fenton sludge. In this process, Cu atoms effectively substituted Fe atoms and regulated the local electronic structure of neighbouring Fe sites, thereby enhancing the catalytic performance in PMS activation for the degradation of Levofloxacin (LEVO) in wastewater. The strong orbital coupling between Fe and Cu, as confirmed by comprehensive characterization and density functional theory (DFT), facilitated the delocalization of d-orbital electrons, thereby enabling efficient electron transfer and redox cycling of Cu2+/Cu+ and Fe3+/Fe2+. This allowed degradation reaction to proceed continuously. The present study will offer a novel approach to the design of Fenton sludge derived catalysts, thereby expanding the utilization of quenching chemistry in solid waste recycling.

Local microenvironment modulation of Pt0/Pt2+ nano-clusters inducing synchronous mass transfer effect to boost catalytic ozonation

Rational catalyst structure design is expected to solve the low O3 utilization and poor molecular mass transfer efficiency in heterogeneous catalytic ozonation (HCO). Herein, Pt/CMK-3 catalyst with confined space to enhance mass transfer was synthesized and employed for CH3SH removal. Unlike fully free diffusion in 0–2.0 wt% Pt/CMK-3 and bulk phase diffusion in 10.0 wt% Pt/CMK-3, removal efficiency of 5.0 wt% Pt/CMK-3 was significantly improved to 97.0%, which was attributed to the effective interfacial diffusion of O3 and CH3SH through local microenvironment modulation of Pt0/Pt2+ nanoclusters (NCs) inducing synchronous mass transfer. Experimental and DFT calculations confirmed the strong electronic interactions between O3 and Pt0 facilitated charge redistribution and preferential O3 activation. AIMD simulation demonstrated that the synchronous difference in mean-square displacements (MSD) and diffusion coefficient (Dc) of CH3SH (Dc=0.022) and O3 (Dc=0.0046) in the confined Pt/CMK-3 system could facilitate CH3SH migrate to Pt2+ through interfacial diffusion. Especially, the d-orbital electrons of Pt NCs interact sequentially with p-orbital electrons of CH3SH and O3 to maintain redox of Pt0/Pt2+. This study provides novel insights on effective mass transfer and kinetic properties of gaseous reaction between oxidant and pollutant by constructing unique interfacial diffusion behaviors.

Anchoring highly surface-exposed Pt single atoms on Ni3S2/Co9S8 with abundant S vacancies triggers d-orbital electron rearrangements for boosted seawater hydrogen evolution

Improving the Pt atoms utilization efficiency on self-supported electrodes is crucial for industrial seawater hydrogen production, but effective strategies are still lacking. Herein, we reported a novel strategy to anchor highly surface-exposed Pt single atoms on Ni3S2/Co9S8 with abundant S vacancies (Pt–Ni3S2/Co9S8–Sv) as a self-supported electrode. Physical characterizations and theoretical calculations confirm that the strong Pt–S electron bridges with the coordinating role of surface S vacancies triggers the d-orbital electron rearrangements and regulates the local electron structures between the Co/Ni and Pt sites. Notably, the Pt–Ni3S2/Co9S8–Sv electrode displays an ultralow overpotential of 18 mV at 10 mA cm−2 in alkaline seawater. More importantly, our Pt–Ni3S2/Co9S8–Sv electrode assembled into an alkaline electrolysis cell can work continuously for 50 h under alkaline seawater @ 60 °C. This work provides a promising strategy for designing highly surface-exposed single-atomic catalyst for large-scale hydrogen evolution through seawater electrolysis.

The structure, magnetism and mechanical properties of L21-type full-Heusler alloy Cr2ZrSi: A first-principles study

Heusler alloy is a widely studied spintronic material in recent years, which has played a huge role in the field of spintronic devices due to its high spin polarization and high Curie temperature. Using first-principles calculation to predict the basic properties of Heusler alloy can not only save experimental costs and time but also provide a reliable theoretical basis for experimental research. This study used a first-principles calculation to study the magnetic and mechanical properties of full-Heusler alloy Cr2ZrSi with an L21-type structure. The research results indicate that the alloy is a half-metallic ferromagnetic material with a theoretical value of 100% spin polarization. The magnetism mainly comes from the asymmetric spin contribution of d-orbital electrons of transition metal atoms and their hybridization. At the same time, this complex hybridization coupling process is also a possible reason for the half-metallic band gaps. In terms of mechanical properties, the Cr2ZrSi alloy exhibits good ductility and anisotropy, with a Debye temperature of 303.848K. Our theoretical research results provide more choices and theoretical basis for subsequent experimental research.

Novel properties of vacancy-ordered perovskite-Cs2BCl6 induced by d-orbital electrons

The all-inorganic lead-free vacancy-ordered perovskite offers a promising avenue toward nontoxic and stable optoelectronic materials. Herein, we present a first-principles study of the structural stability, optical absorption, electronic structure, and mechanical behavior of Cs2BCl6 compounds with B-site substitutions (BGe, Sn, Pb, Cr, Mo, W, Ti, Zr, and Hf). The structural analysis shows that the Cs2BCl6 perovskite with face-centered cubes has a stable chemical environment, especially Cs2HfCl6, Cs2WCl6, and Cs2PbCl6. Hf4+ and W4+ with high-energy d-state external electron configurations can further lower the valence band maximum position of the Cs2BCl6 structures and thus increase the band gap, assisting in tuning the optical absorption and emission properties of these structures in the optoelectronic application. For the light absorption properties of Cs2BCl6 materials, the best light absorption properties have been concluded for Ti4+, Cr4+, and Pb4+-based perovskite in the visible range due to a suitable band gap. Therefore, the excellent optical absorption and electronic properties make these vacancy-ordered perovskites promising candidates for optoelectronic applications.

Theoretical inspection of high-efficiency single-atom catalysts based on π-π conjugated holey graphitic g-C7N3 monolayer: Marvelous water-splitting and oxygen reduction reactions activities

Hydrogen evolution reaction (HER) and oxygen evolution/reduction reaction (OER/ORR) relying on high-performance and low-cost single-atom catalysts (SACs) driven by renewable energy sources offer a sustainable route to carbon-neutral chemicals and fuels. Herein, first-principles calculations were performed to investigate the catalytic HER/OER/ORR activity of a novel graphitic carbon nitride monolayer (g-C7N3) supported single transition metal (TM@g-C7N3). High stability as well as positively charged active site (TM-site) and desirable electrical conductivity lay the foundation for TM@g-C7N3 acting as efficient HER/OER/ORR electrocatalysts. We screened out the non-noble-metal Rh@g-C7N3 SAC exhibiting great potential as the trifunctional electrocatalysts for water splitting (ηHER= 0.06 V and ηOER= 0.46 V) and a metal-air battery (ηORR= 0.28 V) on both kinetic and thermodynamic scales, whereas the Ni@g-C7N3 can be served as a bifunctional OER/ORR catalyst with a low overpotential of 0.33 V/0.31 V, for both of which the high thermodynamic stability and oxidation barrier guarantee their outstanding performances at ambient conditions. The mechanism analysis indicates the filling of d-orbital electrons of TM-atom can play an important role in determining the value of an energy descriptor (ΔGOH*), and the suitable ΔGOH* values make for the TM@g-C7N3 candidates to possess favorable OER/ORR overpotential. Particularly, the Rh-d orbital of Rh@g-C7N3 is evidently hybridized with the OH*-p orbital, resulting in the lone electrons initially distributed in the antibonding orbital pairing up and occupying the downward bonding orbital, ensuring OH* can be adsorbed on Rh@g-C7N3 appropriately. Moreover, multiple-level descriptors including d-band center, COHP, Nd, and φ are used to reveal the origin of the electrocatalytic activity.

Regulated Dual Defects of Bridging Organic and Terminal Inorganic Ligands in Iron-based Metal-Organic Framework Nodes for Efficient Photocatalytic Ammonia Synthesis.

Engineering advantageous defects to construct well-defined active sites in catalysts is promising but challenging to achieve efficient photocatalytic NH3 synthesis from N2 and H2O due to the chemical inertness of N2 molecule. Here, we report defective Fe-based metal-organic framework (MOF) photocatalysts via a non-thermal plasma-assisted synthesis strategy, where their NH3 production capability is synergistically regulated by two types of defects, namely, bridging organic ligands and terminal inorganic ligands (OH- and H2O). Specially, the optimized MIL-100(Fe) catalysts, where there are only terminal inorganic ligand defects and coexistence of dual defects, exhibit the respective 1.7- and 7.7-fold activity enhancement comparable to the pristine catalyst under visible light irradiation. As revealed by experimental and theoretical calculation results, the dual defects in the catalyst induce the formation of abundant and highly accessible coordinatively unsaturated Fe active sites and synergistically optimize their geometric and electronic structures, which favors the injection of more d-orbital electrons in Fe sites into the N2 π* antibonding orbital to achieve N2 activation and the formation of a key intermediate *NNH in the reaction. This work provides a guidance on the rational design and accurate construction of porous catalysts with precise defective structures for high-performance activation of catalytic molecules.

Composition-dependent optical, dielectric and d-orbital electron characteristic of high-throughput horizontal composition gradient Li1-xMgxTi2O4 combinatorial film

The unique physical properties of LiTi2O4 and MgTi2O4 attracted extensive research interest in various fields, including new type batteries and high-temperature superconductors. However, the intricate mechanism governing the d-orbital electron within this system still awaits further excavation. Herein, we employed the combinatorial laser molecular beam epitaxy technique to fabricate a high-quality composition-spread Li1-xMgxTi2O4 film and evaluated its structure, composition, surface morphology and phonon modes by X-ray diffraction, X-ray photoelectron spectroscopy, atomic force microscopy, and Raman scattering spectroscopy. The optical constants and dielectric properties of diverse microregions with varying Li/Mg content over a wide spectral range (189–1658 nm) were measured nondestructively using spectroscopic ellipsometry, revealing the composition-dependent optical properties of Li1-xMgxTi2O4. By fitting the second derivative spectra (d2ε/dE2) using the standard critical point model, five transitions within the detected spectral range were observed. Combining previous analyses and first-principles calculation, we attribute the critical points to crystal field (CF) transition 4A2 →4T1 originating from the spin state of tetrahedral Li/Mg ions, the binding of Ti-related pairs and electron transitions between O-2p to Ti-3d orbits. This exploration of the precise structure of the d-metal band provides a positive reference for the regulation and application of relevant devices.

Exploring the structural stability and related physical properties of FePt2 alloys

The current work presents a theoretical study of the physical properties of several FePt2 ordered structures through first-principles calculations, including structural, magnetic, electronic, mechanical, phonon and thermal properties. The structural stabilities are certified by the enthalpies of formation, elastic constants, and phonon dispersion relationships. The tetragonal I4/mmm structure is energetically favorable compared to other types FePt2 structures including Cmcm, Immm, P63/mmc and P4/nmm structures. The electronic density of states and the contributions of each d-orbital electron to the magnetic moment are analyzed to understand their magnetism. The bulk modulus B values of these FePt2 structures are similar, but the Young's modulus E and shear modulus G as well as the elastic anisotropy are quite different. The thermal properties at finite temperature are estimated by the quasi-harmonic approximation. The I4/mmm structure has higher isothermal bulk modulus, lower thermal expansion coefficient and weaker thermal expansion anisotropy, which is more suitable for high temperature applications than other structures. Also, the sequence of thermal expansion anisotropy is P4/nmm > Immm > Cmcm > I4/mmm (≈P63/mmc).

The synergistic effect in the heteronuclear double-atom catalysts on CO activation: Insights from DFT calculations

In order to identify the synergistic effect in the heteronuclear double-atom catalysts (DACs) on CO activation, the homonuclear and heteronuclear DACs have been designed based on graphene supporter. And the three CO dissociation pathways have been considered using the density functional theory (DFT) calculation. It reveals that the heteronuclear DACs (MoX@NC) possesses higher catalytic ability than the homonuclear DACs (2X@NC) for CO activation. And the unpaired d-orbital electron plays a significant role on CO activation, which can change the magnetic moment of the DACs. The coordination atoms offer similar local coordination environment for the homonuclear and heteronuclear DACs. However, the Bader charge displays that there is a strong electronic interaction between Mo atom and other transition metals of dimer for the heteronuclear DACs. The synergistic effect of the heteronuclear DACs originates from the enhancement of the intermetallic interaction between the Mo atom and other transition metals. The work offers rational guideline for the synthesis of DACs with excellent catalytic performances, and has great potential for application in various catalytic fields.

Adsorption Mechanisms of TM3 (TM = Mo, Ru, Au)-Decorated Tin Sulfide Monolayers for the Decomposition of Gas Components under Fault Conditions in Oil-Immersed Transformers.

Oil-immersed transformers play a pivotal role owing to their environmentally friendly characteristics, compact footprint, and cost-effectiveness. Ensuring the online monitoring of oil-immersed transformers is a fundamental measure to ensure the secure and stable operation of modern power systems. In this paper, metal particle cluster-doped SnS is firstly used in the adsorption and sensing of decomposition components (CO, C2H2) under fault conditions in oil-immersed transformers. The study comprehensively analyzed band structure, differential charge density, density of states, and molecular orbital theory to unveil the adsorption and sensing mechanisms of target gases. The findings suggest that the modification of metal particle clusters can enhance the surface electronic properties of single-layer SnS. In the regions of metal particle clusters and the gas-surface reaction area, electronic activity is significantly heightened, primarily attributed to the contribution of d-orbital electrons of the metal cluster structures. The modified SnS exhibits adsorption capacity in the following order: Ru3-SnS > Mo3-SnS > Au3-SnS. Additionally, the modified material demonstrates increased competitiveness for C2H2, with adsorption types falling under physical chemistry adsorption. Different metal elements exert diverse effects on the electronic distribution of the entire system, providing a theoretical foundation for the preparation of corresponding sensors. The findings in this work offer numerical insights for the further preparation and development of SnS nanosensors, concurrently shedding light on the online monitoring of faults in oil-immersed transformers.

First-principles study of stability and electronic structural properties of Ag/Au/M (Cu, Ni) interface

This study investigated the interface energy, work of adhesion, and electronic structural properties at the Ag/Au/M(Cu,Ni) interface, employing the first-principles method based on density functional theory. First, the structures of various binary and ternary interfaces were optimized. Subsequently, the total density of states (TDOS), partial density of states (PDOS), charge distribution, and bonding characteristics of these interfaces were investigated. Additionally, the interface energy and work of adhesion of these interfaces were calculated. The results indicated that the Ag/Au/Ni interface exhibited higher stability and bonding strength compared to the Ag/Au/Cu interface. The contribution of the PDOS of atoms at the Ag/Au/M(Cu,Ni) interface to the TDOS can be primarily attributed to d-orbital electrons, while s- and p-orbit electrons had minimal influence on PDOS.Notably, d-d orbital hybridization emerged between the d-orbit electrons in Cu and Ni atoms and those in Ag and Au atoms, enhancing structural stability. Two distinct peaks in the TDOS of Ag/Ni, Au/Ni, and Ag/Au/Ni interfaces appeared near the Fermi level, corresponding to d-d orbital hybridization involving Ni, Ag, and Au atoms. At the Ag/Au/Cu and Ag/Au/Ni interfaces, resonance peaks corresponding to the s and p orbits of Ag and the s and p orbits of Au, as well as the d orbits of Ag and Au, indicated the presence of a relatively strong metallic bond between Ag and Au atoms. Furthermore, the Ag/Ni and Au/Ni systems exhibited greater average electron transfer compared to the Ag/Cu and Au/Cu systems. Moreover, atomic bond lengths at the Ag/Au/Ni interface were significantly less than those at the Ag/Au/Cu interface, indicating higher stability of the Ag/Au/Ni interface compared to the Ag/Au/Cu interface.