Electron-electron Interaction Research Articles

Promotion effect of nitrogen doping on the low-temperature NH3-SCR of NO over activated carbon: Characterization and mechanism analysis

Heteroatom nitrogen doping in carbon catalysts is recognized an effective strategy for tailoring the properties of carbon catalysts for various flue gas de-NOx applications. However, accurately discerning the active structures after nitrogen doping and elucidating the promotion effect on low-temperature selective catalytic reduction activity remains a formidable challenge under different nitrogen doping preparation conditions. In this study, a series of nitrogen-doped activated carbon catalysts was synthesized through the L16(45) orthogonal array design method, and the degree of influence of various preparation conditions on de-NOx catalytic activities was also assessed. The optimal preparation conditions determined by range analysis were employed to synthesize NOAC-17, achieving the NO conversion of 95% and N2 selectivity of 99% at 300 °C, respectively. Subsequently, various characterization results proved that nitrogen doping induced the formation of abundant basic groups. The imine, amide, amine, and N-6 groups altered the acid-base of the activated carbon surface and increased the adsorption of acidic NOx. The N-5 and N-Q groups enhanced electronic interaction in the carbon matrix and accelerated electron mobility in the catalytic reaction process. Moreover, the N-6 group played multiple roles beyond the aforementioned effect due to its special structure. It also enhanced the accumulation of oxygen vacancies, which were closely associated with further oxidation of adsorbed NO. The lone electron pair in the N-6 group within the activated carbon framework can alter the polarity of the catalyst, thereby exerting a positive influence on the adsorption and activation of NH3. The nitrogen-doped catalyst identified through range analysis of the orthogonal experiment primarily facilitated the NH3-SCR reaction via the E-R mechanism with supplementary contribution from L-H mechanism at low temperatures. The nitrogen doping conditions obtained for the activated carbon catalyst provide valuable insights for the strategic enhancement of its catalytic performance in low-temperature NH3-SCR reactions.

Origin of Regioselectivity Inversion Tuned by Substrate Electronic Properties in Co(III)-Catalyzed Annulation of N-Chlorobenzamide with Alkenes.

The mechanisms of Co(III)-catalyzed annulations of N-chlorobenzamide with olefins bearing different electronic properties were computationally studied and the origins of regioselectivity reversal were investigated by using energy decomposition analysis (EDA). The alkene migratory insertion step determines the regiochemistry of these reactions. EDA results indicate that the 2,1-insertion with styrene is favored because there is a weaker Pauli repulsion between the cobaltacycle Co-C σ orbital and the olefin π orbital. Conversely, the 1,2-insertion with vinyltrimethylsilane is more favorable than the 2,1-insertion. This is mostly because the increased π electron density can effectively differentiate the stabilizing electronic interactions.

Exploring the Electronic Interactions of Adenine, Cytosine, and Guanine with Graphene: A DFT Study.

This study has provided new insights into the interaction between graphene and DNA nucleobases (adenine, cytosine, and guanine). It compares how each nucleobase interacts with graphene, examining their selectivity and binding energy. The research also explores how these interactions impact the electronic properties of graphene, showing potential applications in graphene-based biosensors and DNA sequencing technologies. Additionally, the findings suggest potential uses in DNA sensing and the functionalization of graphene for various biomedical applications. This study employs density functional theory (DFT) methods, utilizing the B3LYP functional with the 6-311G basis set, to explore the electronic interactions between DNA nucleobases (adenine, cytosine, and guanine) with pure graphene (Gr). We investigate various properties, including adsorption energy, HOMO-LUMO energy levels, charge transfer mechanisms, dipole moments, energy gaps, and density of states (DOS). Our findings indicate that cytosine interacts most favorably with graphene through its oxygen site (Gr-Cyt-O), exhibiting the strongest adsorption. Additionally, adenine's interaction significantly enhances its electronegativity and chemical potential, particularly at the nitrogen position, while decreasing its electrophilicity. Guanine, characterized by the smallest energy gap, demonstrates the highest conductivity among the nucleobases. These results suggest that graphene possesses advantageous properties as an adsorbent for guanine, highlighting its potential applications in biosensor technology.

Unraveling the Multifunctional Sites of Ag Single-Atom and Nanoparticles Confined Within Carbon Nitride Nanotubes for Synergistic Photocatalytic Hydrogen Evolution.

The development of novel nano-single-atom-site catalysts with optimized electron configurations and active water adsorption (*H2O) to release hydrogen protons (*H) is paramount for photocatalytic hydrogen evolution (PHE), a multi-step reaction process involving two electrons. In this study, an atom-confinement and thermal reduction strategy is introduced to achieve synergistic Ag single-atoms (Ag1) and nanoparticles (AgNPs) confined within carbon nitride nanotubes (Ag1+NPs-CN) for enhanced photocatalytic hydrogen evolution. Mechanistic investigations reveal that H2O adsorption/dissociation predominantly occurs at Ag1 sites, while AgNPs sites notably facilitate H2 release, indicating the synergistic effect between Ag1 and AgNPs in the H2 evolution reaction. Furthermore, the effective confining of Ag species is beneficial for trapping electrons in highly active reaction regions, while the "electronic metal-support interactions" (EMSIs) of AgNPs and Ag1-C2N sites regulate the d-band centers and effectively optimize the adsorption/desorption of intermediates in photocatalytic hydrogen evolution, leading to enhanced H2 production performance. This work demonstrates the potential of the construction of synergistic photocatalysts for efficient energy conversion and storage; Hydrogen production; Nanoparticles; Photocatalysis; Single atom; and Synergistic effect.

Stimuli‐Responsive Optical Materials Based on Hypervalent Antimony‐Containing Conjugated Molecules

AbstractStimuli‐responsive materials have been applied for sensor devices because they can transform and amplify various target stimuli into observable signals. Much effort has been devoted to exploring effective molecular designs for obtaining stimuli‐responsive behaviors by taking advantage of the unique optoelectronic properties of π‐conjugated molecules involving various elements. This study focuses on the modulation of the electronic state of the π‐conjugated scaffolds by the oxidation number change of the hypervalent antimony. This study demonstrate that the strength of the intramolecular interaction between hypervalent antimony and the π‐conjugated framework can be tuned with ligand structure, substituent effect, and oxidation number shifts of hypervalent antimony. In particular, the color changes represented by hypsochromic and bathochromic wavelength shifts of optical bands are achieved by the oxidative reaction of hypervalent antimony in the solid state. Significantly, the direction of the color changes can be confidently predicted by quantum chemical calculations. The findings, based on the electronic interaction between π‐conjugated scaffolds and hypervalent main‐group elements, provide logical design strategies for advanced stimuli‐responsive materials.

Chain-Like Pentanuclear Complexes: Syntheses, Crystal Structures and Long-Range Electronic Interactions of Cyanido-Bridged M2Ru3 (M=Fe, Ru).

In this work, we report the design and synthesis of two chain-like pentanuclear cyanido-bridged complexes trans-[Ru(bpy)2(μ-CN)2][cis-Ru(bpy)2(μ-NC)M(dppe)Cp*]2[PF6]4 (M=Fe, 14+; M=Ru, 24+) and the electronic communication properties of their oxidized products 1m+ (m=6, 7, 8) and 2n+ (n=5, 6, 7, 8). The single-crystal X-ray diffraction analysis of 1m+ (m=4, 6, 7) and 24+ show that 14+ and 24+ possess a Z-type array structure, 17+ is a U-type one, and 16+ exhibits both the types. The investigations indicate that both 1 and 2 show an extraordinarily strong electronic interaction between the two side Ru across the central NC-Ru-CN, leading to the formation of a fully delocalized cyanidometal Ru-Ru-Ru bridge for both three-electron oxidized states 17+ and 27+. Moreover, it should be noted that in 1 there exists no electronic interaction between the two terminal Fe ions. Upon substitution of Fe by Ru, however, 2 exhibits an electronic interaction between the two terminal metal ions across the trinuclear cyanidometal CN-Ru-NC-Ru-CN-Ru-NC bridge which is up to 20 Å.

Lattice Strain Regulated by Hetero/Homo Atom Interface Merging on NiMo Nanocluster for High-Performance Hydrogen Production.

Lattice strain engineering represents a cutting-edge approach capable of delivering enhanced performance across various applications. The lattice strain can affect the performance of electrochemical catalysts by changing the binding energy between the surface-active sites and intermediates. In this work, lattice strain is regulated through a homo/heterogeneous atomic interface merging. The strong lattice strain and electronic interactions between Ni and Mo facilitated the reaction kinetic of HER. The prepared NiMo@SSM exhibits excellent HER catalytic performance with 70 mV overpotential at the current density of 10 mA cm-2 and long-term stability. The method of controlling lattice strain through hetero/homo atom interface merging provides a new strategy for designing high-performance alkaline HER electrocatalysts.

Highly Active and Stable Cu-Cd Bimetallic Oxides for Enhanced Electrochemical CO2 Reduction.

Electrochemical reduction of carbon dioxide (CO2) can produce value-added chemicals such as carbon monoxide (CO) and multicarbon(C2+). However, the complex reaction pathways of CO2electro-reduction reaction (CO2RR) greatly limit the product selectivity and conversion efficiency. Herein, the Cu-Cd bimetallic oxides catalyst was designed and applied for the CO2RR. The optimized 4.73%Cd-CuO exhibits remarkable electrocatalytic CO2RR activity for selective CO production in H-cell using 0.5 M 1-butyl-3-methylimidazolium hexafluorophosphate ([Bmim]PF6)/MeCN as electrolyte. The Faradaic efficiency of CO (FE(CO)) can be maintained above 90% over a wide potential range of -2.0 to -2.4 V vs. Ag/Ag+. Particularly, the catalyst achieves an impressive FE(CO) of 96.3% with a current density of 60.7 mA cm-2at -2.2 V vs. Ag/Ag+. Furthermore, scaling up the 4.73%Cd-CuO catalyst into a flow cell can reach 56.64% FE of C2+products (ethylene, ethanol and n-propanol) with a current density as high as 600 mA cm-2steadily.The excellent CO2RR performance of the as-synthesized 4.73%Cd-CuOcan be mainly attributed to the introduction of CdO to improve the ability of CuO to activate CO2, the electronic interactions between Cu and Cd can boostactivation and conversionkey intermediates of CO2RR and ensure the continuous stability of4.73%Cd-CuOin electrolysis process.

Enantioselective Synthesis of Axially Chiral Allylic Nitriles via Nickel-Catalyzed Desymmetric Cyanation of Biaryl Diallylic Alcohols.

Axially chiral nitriles are common motifs in organic photoelectric materials, biological compounds, and agrochemicals. Unfortunately, the limited synthetic approaches to axially chiral nitriles have impeded their availability. Herein, we report the first nickel-catalyzed desymmetric allylic cyanation of biaryl allylic alcohols for the synthesis of axially chiral nitrile structures in high yields with excellent enantioselectivities (up to 90 % yield and >99 % ee). This process enables the synthesis of a diverse range of axially chiral allylic nitriles bearing β,γ-unsaturated alcohol moieties. Leveraging the allylic alcohol and cyano groups as versatile functionalization handles allow for further derivatization of these axially chiral frameworks. Density functional theory (DFT) calculations suggest that both steric and electronic interactions play crucial roles in determining the enantioselectivity of this transformation. Moreover, this mild and facile protocol is also applicable for gram-scale preparation of the chiral nitriles.

Enantioselective Synthesis of Axially Chiral Allylic Nitriles via Nickel‐Catalyzed Desymmetric Cyanation of Biaryl Diallylic Alcohols

AbstractAxially chiral nitriles are common motifs in organic photoelectric materials, biological compounds, and agrochemicals. Unfortunately, the limited synthetic approaches to axially chiral nitriles have impeded their availability. Herein, we report the first nickel‐catalyzed desymmetric allylic cyanation of biaryl allylic alcohols for the synthesis of axially chiral nitrile structures in high yields with excellent enantioselectivities (up to 90 % yield and >99 % ee). This process enables the synthesis of a diverse range of axially chiral allylic nitriles bearing β,γ‐unsaturated alcohol moieties. Leveraging the allylic alcohol and cyano groups as versatile functionalization handles allow for further derivatization of these axially chiral frameworks. Density functional theory (DFT) calculations suggest that both steric and electronic interactions play crucial roles in determining the enantioselectivity of this transformation. Moreover, this mild and facile protocol is also applicable for gram‐scale preparation of the chiral nitriles.

Controlling Metal-Support Interactions to Engineer Highly Active and Stable Catalysts for COx Hydrogenation.

This perspective focuses on the modulation of metal-support interaction (MSI) in catalysts for COx hydrogenation, highlighting their profound impact on catalytic performance. Firstly, it outlines different strategies, including the use of highly reducible oxides and moderate reduction treatments, which induce the classical strong metal-support interaction (SMSI) effect and the electronic metal-support interaction (EMSI) effect. Morphology engineering and crystalline phase manipulation of oxides presented as effective methods to control EMSI are also discussed. The discrimination of SMSI and EMSI can be achieved using oxides with low encapsulation tendencies, such as ZrO2, which supports electronic modifications without or minimizing the overgrowth issues, optimizing the catalytic performance for methanation. Then, the synergy between Cu and ZnO in methanol synthesis, enhanced by SMSI, is emphasized inside. Optimizing support oxides to control oxygen vacancies enhances the catalytic performance of CO2 hydrogenation to methanol. Perspectives for the future research on the fundamental understanding of structure-MSI-performance relationship for catalyst design is discussed.

Surface Plasmon Polariton Photoluminescence Enhancement of Single InP Nanowires with InAsP Quantum Wells

A significant (up to 4 times) photoluminescence enhancement of single InP/InAsP/InP nanowires transferred onto a silicon oxide‐covered silver layer on silicon substrate with a metal surface roughness level of less than 1 nm and a dielectric thickness of 5 nm has been demonstrated. This phenomenon is explained by the interaction of electron–hole pairs in the semiconductor with surface plasmon polaritons. The photoluminescence kinetics and results of modeling confirm the indicated enhancement mechanism.

Carrier localization induced by electron-electron interaction and its impact on the electrical transport and magnetic properties of nonstoichiometric IrMnSn

Carrier localization induced by electron-electron interaction and its impact on the electrical transport and magnetic properties of nonstoichiometric IrMnSn

Dual Modulation of Hydroxyl Action on Ruthenium Surface by Single‐Atom Supports for Alkaline H2 Evolution

AbstractRuthenium (Ru)‐based catalysts are known to accelerate the slow kinetics of the alkaline hydrogen evolution reaction (HER). However, enhancing the transfer kinetics of adsorbed hydroxyl (OHad) remains challenging. Herein, a dual‐regulation strategy is presented to alleviate OH blockage on the catalyst surface, using a cluster‐level Ru electrocatalyst supported by single‐atom CoN4 generated in situ on carbon nanotubes (CNTs). Experimental and theoretical studies demonstrate that introducing oxophilic single‐atom CoN4 can mitigate the strong interaction between Ru and OHad by directly competing for OHad on the Ru surface, thereby preventing Ru site poisoning. Meanwhile, single‐atom CoN4 effectively modifies the electronic structure of Ru atomic clusters (ACs), indirectly optimizing the energy barriers for OH desorption at the Ru interface and promoting OHad release. The electronic interaction between Ru ACs and CoN4 also inhibits Ru atom migration, significantly enhancing catalytic stability. The resulting catalyst shows excellent HER activity at 10 mA cm−2 with a low overpotential of 15 mV in alkaline solution and remains stable at 200 mA cm−2 for over 1000 h. An alkaline anion‐exchange membrane water electrolyzer (AEMWE) using this catalyst can exhibit an ultralow potential (1.785 V at 1 A·cm−2) and high stability at 500 mA·cm−2.

A study of nuclear radiation interaction parameters of some plant based radio-protective compounds

In radiation therapy, various radioprotective materials protect normal cells from the damage produced by ionizing radiation. Plant-based chemical compounds possess antioxidant properties and can scavenge free radicals produced by nuclear radiation. Determining radiation shielding parameters and understanding how nuclear radiation interacts with plant-based radioprotectors are crucial for choosing the optimal plant-based radioprotectors. In the present work, the interaction of gamma, neutron, electron, proton, and alpha particles with plant-based radioprotectives such as ferulic acid, genistein, hesperidin, lycopene, psoralidin, sesamol, troxerutin, vanillin, and zingerone has been studied. The interaction parameters such as MAC, Z eff , EBF, and EABF for gamma energy, MAF for thermal and fast neutrons, and MSP for electrons, protons, and alpha have been calculated for the plant-based radioprotectors using the software EpiXs, PyMLBUF, NGCal, ESTAR, PSTAR, and ASTAR. Results show that genistein and lycopene show high and low effective atomic numbers in the higher energy region of gamma photons, respectively. The neutron mass attenuation factor is found to be highest for lycopene and lowest for genistein for both thermal and fast neutrons. Among the selected plant-derived radioprotectives, troxerutin and lycopene are the most effective plant-based compounds for gamma and neutron radiation therapy applications. The shielding parameters of selected plant-based radioprotector materials are compared with those of some chemical radioprotectors. Besides, the shielding parameters of selected plant-based radioprotector materials are comparable to chemical radioprotectors except for lycopene.

Engineering MXene Surface via Oxygen Functionalization and Au Nanoparticle Deposition for Enhanced Electrocatalytic Hydrogen Evolution Reaction.

MXene, a family of 2D transition metal carbides and nitrides, presents promising applications in electrocatalysis. Maximizing its large surface area is key to developing efficient non-noble-metal catalysts for the hydrogen evolution reaction (HER). In this study, oxygen-functionalized Ti3C2Tx MXene (Ti3C2Ox) is synthesized and deposited gold nanoparticles (Au NPs) onto it, forming a novel composite material, Au-Ti3C2Ox. By selectively removing other functional groups, mainly -O functional groups are retained on the surface, directing electron transfer from Au NPs to MXene due to electronic metal-support interaction (EMSI), thereby improving the catalytic activity of the MXene surface. Additionally, the interaction between Au NPs and -O functional groups further enhanced the overall catalytic activity, achieving an overpotential of 62 mV and a Tafel slope of 40.1 mV dec-1 at a current density of -10 mA cm-2 in 0.5 m H2SO4 solution. Density functional theory calculations and scanning electrochemical microscopy with ≤150 nm resolution confirmed the enhanced catalytic efficiency due to the specific interaction between Au NPs and Ti3C2Ox. This work provides a surface modification strategy to fully utilize the MXene surface and enhance the overall catalytic activity of MXene-based catalysts.

Synergistic Electronic Interaction in PdCu Alloy/TiO2-NSs for Ambient Efficient Dehydrogenation of Formic Acid.

Palladium-based catalysts are remarkable in endorsing hydrogen (H2) generation through formic acid (HCOOH, FA) dehydrogenation under near-ambient conditions. Hydrogen energy efficiency depends on high-performance catalyst design. In this study, Pd-Cu nanoalloy catalysts with mutable atomic ratios are successfully fabricated on TiO2 nanosheets (TiO2-NSs).The synergistic electronic interactions between Palladium (Pd) and copper (Cu) are revealed through a density of states (DOS) analysis of alloy supported over a mixed valence state of Ti linked to oxygen vacancies (Vo) in TiO2-NSs, Enhanced adsorption of target molecules reveals novel active sites for Formic acid dehydrogenation (FAD), with O─H bond cleavage via HCOO formate intermediate preceding C─H and C─O bond cleavage. Experimental and theoretical research demonstrates that the Pd-Cu/TiO2-NSs (3:7) catalyst d electron redistribution and d-band center shift lower the activation energy for O─H bond cleavage, exhibit superior H2 production than pure Pd and Cu, increasing Pd electron density due to synergistic effects from reactive crystal facets, defects, and strong metal support interactions (SMSI), lowering the activation energy for HCOOH dissociation step, generating carbon dioxide (CO2) and H2 with a unprecedented high turnover frequency (TOF) of 6268 molH2.h-1.molPd-1 at 303K with activation energy (Ea) of 15 KJ mol-1. This attempt models an efficient HCOOH-to-hydrogen catalyst.

Tropone Hydrazides in [10+2]‐Hetero‐Higher‐Order Cycloaddition for the Synthesis of Tetrahydropyridazine Derivatives

Abstract[10+2]‐Hetero‐higher‐order cycloaddition between tropone hydrazides (acting as 10π‐components) and 3‐alkylidene oxindoles (acting as 2π‐components) has been established. Under Brønsted base catalysis the reaction proceeded in a fully peri‐ and diastereoselective manner with the stereochemical outcome governed mainly by electronic interactions. Following such a strategy, a series of structurally diverse tetrahydropyridazines were prepared in 30–70% yields. Furthermore, the potential of the obtained cycloadducts has been confirmed in selected chemoselective transformations.

Electron scattering study on acetic acid and methyl formate

Abstract In this work we report the results of a theoretical calculation of the elastic, differential scattering, and excitation cross-sections on electron interactions with the C2H4O2 isomers (methyl formate and acetic acid) using the ab initio R-matrix method in the energy range of 0.1-20 eV. The computations were performed using static exchange (SE), static exchange plus polarization (SEP) and Close-Coupling (CC) models with electronic structure calculation for these molecules performed using GAMESS. In the electron scattering cross section we have identified π* type resonance in both the isomers. Ionization cross-sections for both the molecules from ionization threshold to 500 eV using BEB method are also presented here. We endeavoured to explore the isomeric effect on various cross sections among these two isomers and included the third isomer, namely glycolaldehyde, as reported in our previous publication.

Fate of surface gaps in magnetic topological insulators

Abstract In magnetic topological insulators, the surface states can exhibit a gap due to the breaking of time-reversal symmetry. Various experiments, while suggesting the existence of the surface gap, have raised questions about its underlying mechanism in the presence of different magnetic orderings. Here, we demonstrate that magnon-mediated electron-electron interactions, whose effects are not limited to the surfaces perpendicular to the magnetic ordering, can significantly influence surface states and their effective gaps. On the surfaces perpendicular to the spin quantization axis, many-body interactions can enhance the band gap to a degree that surpasses the non-interacting scenario. Then, on surfaces parallel to the magnetic ordering, we find that strong magnon-induced fermionic interactions can lead to features resembling a massless-like gap. These remarkable results largely stem from the fact that magnon-mediated interactions exhibit considerable long-range behavior compared to direct Coulomb interactions among electrons, thereby dominating the many-body properties at the surface of magnetic topological insulators.