Modification Of Electronic Structure Research Articles

Enhancing photocatalytic H2O2 production with Au co-catalysts through electronic structure modification

Gold-based co-catalysts are a promising class of materials with potential applications in photocatalytic H2O2 production. However, current approaches with Au co-catalysts show limited H2O2 production due to intrinsically weak O2 adsorption at the Au site. We report an approach to strengthen O2 adsorption at Au sites, and to improve H2O2 production, through the formation of electron-deficient Auδ+ sites by modifying the electronic structure. In this case, we report the synthesis of TiO2/MoSx-Au, following selective deposition of Au onto a MoSx surface which is then further anchored onto TiO2. We further show that the catalyst achieves a significantly increased H2O2 production rate of 30.44 mmol g−1 h−1 in O2-saturated solution containing ethanol. Density functional theory calculations and X-ray photoelectron spectroscopy analysis reveal that the MoSx mediator induces the formation of electron-deficient Auδ+ sites thereby decreasing the antibonding-orbital occupancy of Au-Oads and subsequently enhancing O2 adsorption. This strategy may be useful for rationally designing the electronic structure of catalyst surfaces to facilitate artificial photosynthesis.

Boosting Electrocatalytic Ethylene Epoxidation by Single Atom Modulation.

The electrochemical synthesis of ethylene oxide (EO) using ethylene and water under ambient conditions presents a low-carbon alternative to existing industrial production process. Yet, the electrocatalytic ethylene epoxidation route is currently hindered by largely insufficient activity, EO selectivity, and long-term stability. Here we report a single atom Ru-doped hollandite structure KIr4O8 (KIrRuO) nanowire catalyst for efficient EO production via a chloride-mediated ethylene epoxidation process. The KIrRuO catalyst exhibits an EO partial current density up to 0.7 A cm-2 and an EO yield as high as 92.0 %. The impressive electrocatalytic performance towards ethylene epoxidation is ascribed to the modulation of electronic structures of adjacent Ir sites by single Ru atoms, which stabilizes the *CH2CH2OH intermediate and facilitates the formation of active Cl2 species during the generation of 2-chloroethanol, the precursor of EO. This work provides a single atom modulation strategy for improving the reactivity of adjacent metal sites in heterogeneous electrocatalysts.

Boosting Electrocatalytic Ethylene Epoxidation by Single Atom Modulation

AbstractThe electrochemical synthesis of ethylene oxide (EO) using ethylene and water under ambient conditions presents a low‐carbon alternative to existing industrial production process. Yet, the electrocatalytic ethylene epoxidation route is currently hindered by largely insufficient activity, EO selectivity, and long‐term stability. Here we report a single atom Ru‐doped hollandite structure KIr4O8 (KIrRuO) nanowire catalyst for efficient EO production via a chloride‐mediated ethylene epoxidation process. The KIrRuO catalyst exhibits an EO partial current density up to 0.7 A cm−2 and an EO yield as high as 92.0 %. The impressive electrocatalytic performance towards ethylene epoxidation is ascribed to the modulation of electronic structures of adjacent Ir sites by single Ru atoms, which stabilizes the *CH2CH2OH intermediate and facilitates the formation of active Cl2 species during the generation of 2‐chloroethanol, the precursor of EO. This work provides a single atom modulation strategy for improving the reactivity of adjacent metal sites in heterogeneous electrocatalysts.

Tuning structure, stability and magnetism in vanadium doped zinc sulfide for spintronic applications: Insights from first-principles and Monte Carlo approaches

This work utilizes a multi-scale computational approach combining first-principles density functional theory (DFT) and Monte Carlo statistical simulations to provide fundamental insights into the impacts of vanadium (V) doping on the structural, electronic, magnetic, and thermodynamic properties of wurtzite zinc sulfide (ZnS). 2 × 2 × 2 ZnS supercells with controlled V doping concentrations from 12.5%–25% substituting zinc sites were constructed. The introduction of V dopants induces systematic expansions in lattice parameters and cell volume, attributed to the larger ionic radius of V2+ than Zn2+, while the average compressibility shows minimal variation. However, V incorporation is found to soften ZnS by over 15% at higher dopant contents, increasing compliance and anisotropy. Stable ferromagnetic spin couplings emerge, mediated by host carriers without precipitating V secondary phases. The band structure develops half-metallic electronic properties with the lifting of spin degeneracy and preferential spin-up band metallicity induced by V-3d and S-3p hybridization effects. This results in 100% spin polarization at the Fermi level. Monte Carlo simulations based on a tight-binding Hamiltonian constructed from maximally localized Wannier functions to accurately calculate the exchange interactions between V spins successfully reproduce the magnetic phase transition behavior. The results confirm high Curie temperatures exceeding 300 K at 25% V, attributable to the significant strengthening of short-range ferromagnetic couplings over antiferromagnetic interactions. The integrated computational approach provides fundamental insights into the microscopic origin of carrier-mediated ferromagnetism in V-doped wurtzite ZnS dilute magnetic semiconductors. The systematic first-principles calculations and statistical mechanics modeling establish clear structure–property relationships linking V doping configurations and concentrations to tuned mechanical response, enhanced stability, electronic structure modifications, spin polarization, and magnetic ordering temperatures in ZnS. The results present design pathways and predictive capabilities to guide experimental efforts toward emerging high-performance magnetic materials for spintronic technologies.

Tuning the electrocatalytic activity of MoS2 nanosheets via the in situ hybridization with ruthenium and graphene network

The quest for highly efficient, stable, and non-precious electrocatalysts as alternatives to Pt in the hydrogen evolution reaction (HER) at ambient temperature is paramount. Two-dimensional (2D) layered transition metal dichalcogenides (TMDs), notably MoS2, have emerged as promising noble-metal-free candidates. However, MoS2′s limited active edge sites and sluggish electron transfer kinetics present challenges in achieving efficient HER activity under both acidic and basic conditions. In this study, we introduce a composite catalyst composed of 2D MoS2 nanosheets enveloped by graphene networks, with uniform dispersion of ruthenium (Ru) nanoparticles within the extended 2D structure. This ternary hybrid catalyst exhibits excellent catalytic activity, with a low onset overpotential of 60 mV at 10 mA cm−2, a small Tafel slope of 38 mV dec-1, and remarkable durability during continuous 10-hour operation at 100 mV potential in 1.0 M KOH, without substantial activity loss. The conductive graphene support effectively prevents the restacking of exfoliated MoS2 nanosheets, enhancing mass transport and charge transfer kinetics. Ru incorporation induces the partial phase transformation of MoS2 from its trigonal (2H) to octahedral (1 T) phase, concurrently generating sulfur vacancies. The induced phase transformation not only activates the inert basal planes of MoS2 but also reduces the energy barrier for the adsorption/desorption of H* intermediates. Beyond the structural advantages, the intrinsic synergistic effects, primarily related to electronic structure modulation and defect engineering, contribute significantly to the enhanced electrochemical HER performance. In summary, this study not only introduces an efficient, cost-effective alternative to Pt-based electrocatalysts but also lays the foundation for designing other TMD-based hybrid catalysts, characterized by abundant exposed active sites and reduced barriers for hydrogen binding energy, thereby advancing electrochemical hydrogen production.

Electronic Structure Design of Transition Metal-Based Catalysts for Electrochemical Carbon Dioxide Reduction.

With the increasingly serious greenhouse effect, the electrochemical carbon dioxide reduction reaction (CO2RR) has garnered widespread attention as it is capable of leveraging renewable energy to convert CO2 into value-added chemicals and fuels. However, the performance of CO2RR can hardly meet expectations because of the diverse intermediates and complicated reaction processes, necessitating the exploitation of highly efficient catalysts. In recent years, with advanced characterization technologies and theoretical simulations, the exploration of catalytic mechanisms has gradually deepened into the electronic structure of catalysts and their interactions with intermediates, which serve as a bridge to facilitate the deeper comprehension of structure-performance relationships. Transition metal-based catalysts (TMCs), extensively applied in electrochemical CO2RR, demonstrate substantial potential for further electronic structure modulation, given their abundance of d electrons. Herein, we discuss the representative feasible strategies to modulate the electronic structure of catalysts, including doping, vacancy, alloying, heterostructure, strain, and phase engineering. These approaches profoundly alter the inherent properties of TMCs and their interaction with intermediates, thereby greatly affecting the reaction rate and pathway of CO2RR. It is believed that the rational electronic structure design and modulation can fundamentally provide viable directions and strategies for the development of advanced catalysts toward efficient electrochemical conversion of CO2 and many other small molecules.

Third-Order Nonlinear Optical Modulation Behavior of Photoresponsive Bimetallic MOFs.

Bimetallic metal-organic frameworks (MOFs) capable of sensing external stimuli will provide more possibilities for further regulating third-order nonlinear optical (NLO) properties. In this work, we synthesized bimetallic MOFs (ZnCu-MOF and ZnCd-MOF) through central metal exchange using a photoresponsive Zn-MOF as a precursor. Compared with Zn-MOF, both ZnCu-MOF and ZnCd-MOF exhibit significantly enhanced third-order NLO absorption properties. This is mainly attributed to the introduction of metal ions with different electron configurations that can adjust the bandgap of MOFs and enhance electron delocalization, thus promoting electron transfer. Interestingly, the bimetallic MOFs show a transition from reverse saturation absorption (RSA) to saturation absorption (SA) after exposure to ultraviolet irradiation, as they retain the properties of directional photogenerated electron transfer. Photoresponsive bimetallic MOFs not only have the effect of bimetallic modulation of electronic structures but also have the characteristics of photoinduced electron transfer, exhibiting diversified optical properties. These findings provide a novel method for the development of multifunctional NLO materials.

Coordination engineering and electronic structure modulation of FeNi dual-single-atoms encapsulated in N, P-codoped 3D hierarchically porous carbon electrocatalyst for synergistically boosting oxygen reduction reaction

With the increasing energy and environmental issues in recent years, it is vital to explore inexpensive and highly activated oxidation reduction reaction (ORR) catalysts for next generation energy storage and conversion devices such as zinc-air batteries. Herein, FeNi dual-single-atoms were efficiently encapsulated into N,P-codoped 3D hierarchically porous carbon (FeNi DSAs/N,P-PC) by a simple one-step pyrolysis. The resulting FeNi DSAs/N,P-PC catalyst exhibited the better ORR activity with the positive onset potential (Eonset = 1.02 V) and half-wave potential (E1/2 = 0.88 V) over commercial Pt/C, and performed well in the assembled zinc-air batteries (peak power density of 124.73 mW cm−2,and long-term charge/discharge stable cycling for 330 h). The XAFS analysis clearly displayed the coordination structure and interactions of the FeNi dual atoms. The DFT calculations show that P-O bonds have great influence on the electronic structure of the FeNi dual atoms. And Ni site can effectively modulate the electronic structure of the Fe site to promote charge transfer and further reduce the energy barrier of the rate-limiting step. This strategy provides a viable strategy for development of low-cost high-performance transition metal diatomic catalysts suitable for energy conversion and storage devices.

Strain-induced modulation of electronic structure in correlated Dirac semimetal Pv-CaIrO3 epitaxial thin films

Perovskite CaIrO3 is theoretically predicted to be a Dirac node semimetal near the Mott transition, which possesses a considerable interplay between electron correlations and spin–orbit coupling. Electron correlations can significantly tune the behavior of relativistic Dirac fermions. Here, we have grown high-quality perovskite CaIrO3 thin films on different substrates using oxide molecular beam epitaxy to modulate both electron correlations and Dirac electron states. Through in situ angle-resolved photoemission spectroscopy, we demonstrate a systematic evolution of the bandwidth and effective mass of Jeff=1/2 band in perovskite CaIrO3 induced by strain. The bandwidth of the Jeff=1/2 band undergoes an evident increase under in-plane compressive strain, which could be attributed to the weakening of electron correlations. The compressive strain can potentially shift the position of the Dirac node relative to the Fermi level and play a vital role in the transition from hole-type to electron-type transport characteristics. Our work provides a feasible approach for manipulating the topological Dirac electron states by engineering the strength of electron correlations.

Electronic Structure Modulation of Oxygen-Enriched Defective CdS for Efficient Photocatalytic H2 O2 Production.

Artificial photosynthesis for hydrogen peroxide (H2 O2 ) presents a sustainable and environmentally friendly approach to generate clean fuel and chemicals. However, the catalytic activity is hindered by challenges such as severe charge recombination, insufficient active sites, and poor selectivity. Here, a robust strategy is proposed to regulate the electronic structure of catalyst by the collaborative effect of defect engineering and dopant. The well designed oxygen-doped CdS nanorods with S2- defects and Cd2+ 4d10 electron configuration (CdS-O,Sv ) is successfully synthesized, and the Cd2+ active sites around S defects or oxygen atoms exhibit rapid charge separation, suppressed carrier recombination, and enhanced charge utilization. Consequently, a remarkable H2 O2 production rate of 1.62mmolg-1 h-1 under air conditions is acquired, with an apparent quantum yield (AQY) of 9.96% at a single wavelength of 450nm. This work provides valuable insights into the synergistic effect between defect and doping on catalytic activity.

Dipole modification of the surface electronic structure of III–V semiconductors

A simple electrostatic model is proposed to account for the effect of dipoles associated with surface chemical bonds on the electronic structure of the semiconductor surface. In accordance with the model, the formation of the dipolar surface chemical bonds can change the width of the surface depletion layer leaving the surface band bending nearly intact. In addition, the surface dipoles can redistribute charge localized at surface states, which can modify surface recombination velocity of the semiconductor. The model can explain recently obtained experimental data on the electronic passivation of n-InP(100) surface with different sulfide solutions.

Electronic structure modulation of iron sites with fluorine coordination enables ultra-effective H2O2 activation

Electronic structure modulation of active sites is critical important in Fenton catalysis as it offers a promising strategy for boosting H2O2 activation. However, efficient generation of hydroxyl radicals (•OH) is often limited to the unoptimized coordination environment of active sites. Herein, we report the rational design and synthesis of iron oxyfluoride (FeOF), whose iron sites strongly coordinate with the most electronegative fluorine atoms in a characteristic moiety of F-(Fe(III)O3)-F, for effective H2O2 activation with potent •OH generation. Results demonstrate that the fluorine coordination plays a pivotal role in lowering the local electron density and optimizing the electronic structures of iron sites, thus facilitating the rate-limiting H2O2 adsorption and subsequent peroxyl bond cleavage reactions. Consequently, FeOF exhibits a significant and pH-adaptive •OH yield (~450 µM) with high selectivity, which is 1 ~ 3 orders of magnitude higher than the state-of-the-art iron-based catalysts, leading to excellent degradation activities against various organic pollutants at neutral condition. This work provides fundamental insights into the function of fluorine coordination in boosting Fenton catalysis at atomic level, which may inspire the design of efficient active sites for sustainable environmental remediation.

Zinc Dopant-Induced Modulation of Electronic Structure and Defect Emissions in Monoclinic Gallium Oxide

Zinc Dopant-Induced Modulation of Electronic Structure and Defect Emissions in Monoclinic Gallium Oxide

Improving stability, mechanical and electronic properties of pentadiamond by doping with alkali or alkaline-earth metals: A first-principles investigation

Pentadiamond (PD), a recently proposed carbon allotrope, has garnered considerable attention owing to its unique covalent framework comprising both sp2 and sp3 carbon atoms. Despite its intriguing structure with potentially useful thermal, electronic and optical properties, PD is supposed to be thermodynamically very unstable, due to the strain imposed by adjacent pentagonal rings in the carbon framework, which poses a major concern for its practical production. Here, we employ first-principles simulations to demonstrate that inserting alkali or alkaline-earth metals into the bigger cavities of PD significantly enhances its thermodynamic stability. Moreover, the resulting doped materials exhibit high kinetic stability at high temperatures typical for synthesis of fullerenes and metallofullerenes. We systematically investigate the structures and the modulation of mechanical properties and electronic structures of metal-doped PDs. Most remarkably, beryllium is revealed to be the energetically most favorable dopant among the metals considered. Be-doped PD exhibits an increased shear and Young's moduli (by about 55.6 % and 44.4 %, respectively), along with a substantially reduced Poisson's ratio (from 0.23 to 0.14). Furthermore, doping with Be transforms PD from an indirect-gap material to a direct-gap semiconductor, narrowing the band gap from 3.58 eV to 2.67 eV. We hope these findings may stimulate the experimental endeavors to synthesize metal-doped PD materials and unlock their potential applications.

Rational modulation of electronic structure in PtAuCuNi alloys boosts efficient electrocatalytic ethanol oxidation assisted with energy-saving hydrogen evolution

Compared to conventional electrocatalytic water splitting, electrocatalytic ethanol oxidation reaction (EOR) along with hydrogen production is considered a more energy-efficient strategy. Herein, we prepared a type of novel quaternary alloy catalyst (PtAuCuNi@NF) that exhibits excellent activity for EOR (0.215 V at 10 mA cm−2) and hydrogen evolution reaction (HER) (7 mV at 10 mA cm−2). Experimental results demonstrated that both Cu and Ni modulated the electronic environment around Pt and Au. The electron-rich active center facilitates the rapid adsorption and dissociation of reactants and intermediates for both EOR and HER. Impressively, in the ethanol-assisted overall water splitting (E-OWS), a current density of 10 mA cm−2 was achieved at 0.28 V. Moreover, an advanced acid-base self-powered system (A-Bsps) that can achieve a self-powered voltage of 0.59 V was assembled. Accordingly, the self-driven hydrogen production with zero external power supply was realized by integrating A-Bsps with the E-OWS equipment. The interesting results can provide a feasible strategy for designing and developing advanced nanoalloy-based materials for clean energy integration and use in various fields.

Modulate the surface charge toward efficient hydrogen evolution reaction: Electronic structure engineering of MoB-Ni3B interface

Rationally regulated the surface electronic structure of catalysts hold the key to enhance the kinetics of hydrogen evolution reaction (HER). Herein, we propose an electronic structure engineering strategy to modulate the surface charge of Ni3B by introducing MoB for high-efficient HER. The MoB-Ni3B interface exhibits characteristic lattice expansion and results in electron modulation between the Ni3B and MoB. Density functional theory calculations further indicate that the introduction of MoB leads to electron enrichment around Ni sites, which further activate Ni sites, weaken the adsorption of hydrogen intermediates and thus facilitate the unfavorable hydrogen desorption, resulting in the Gibbs free adsorption energy closer to zero. As expected, the hierarchical MoB-Ni3B displays an ultra-low overpotential (η10 = 35 and 57 mV for reaching a current density of −10 mA cm−2) in 1.0 M KOH and 0.5 M H2SO4, which is comparable to the commercial Pt catalyst and confirms the positive effect of the modulation of electronic structure on the kinetics and catalytic activity. The effectiveness of the electronic structure engineering strategy is expected to shed light on the construction of more advanced electrocatalysts.

Preparation and Study the Properties of PVDF/PEO/WO2 Hybrid Nanocomposite Thin Films Prepared by a Spin Coating Method

In this work, using the spin coating method to create polyvinylidene fluoride (PVDF)/polyethylene oxide (PEO) thin films, the effects of nano-tungsten oxide (WO2) doping were investigated. The novelty of this research lies in its investigation of varying weight concentrations of WO2 nanoparticles (NPs) within the composite films. Comprehensive characterization techniques were employed, including structural analysis via X-ray diffraction (XRD), which revealed a clear and prominent peak in the XRD of the PVDF/PEO films, and the films' polycrystalline nature with tetragonal structures. The grain size was noted to increase with higher WO2 NPs doping. Field emission scanning electron microscopy (FE-SEM) showed hexagonal-like α-phase PVDF crystals and uniform distribution of WO2 NPs. Furthermore, Fourier-transform infrared spectroscopy (FTIR) confirmed the characteristics of PVDF/PEO and identified specific doping compounds, confirming successful incorporation. The optical transmittance spectra unveiled the films' optical band gap energy, optical transition types, and absorption characteristics, where novelty emerged as the band gap energy significantly increased from 3.0 eV to 3.64 eV with an increased WO2 NPs weight doping percentage, signifying profound electronic structure modifications and potential applications in optoelectronics and sensors.

Modulating the pore and electronic structure for targeted recovery of platinum: Accelerated kinetic and reinforced coordination

Adsorption for recovery of low-concentration platinum (Pt) from the complex composition of acidic digestates was challenging because of slow kinetic and poor affinity. It was expected to be overcome by the improvement of pore size distribution and adsorption site activity. Herein, a series of Prussian blue etchings (PBE) with porosity-rich and activity-high cyano (CN) was synthesized to recover low-concentration Pt. The N2 isotherm results showed that the pore structure evolved from mesoporous to microporous. The Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), and density functional theory (DFT) calculations results revealed that the modulation of electronic structure converted FeII to FeIII in [FeII(CN)6]4−. The coexistence of micro- and meso-pore structures provided channels to accelerate adsorption and ensured PtII enrichment. The regulation of Fe valence state activated CN, which reinforced the strength of coordination interaction between Pt and Fe-CN- at N-atom. The adsorption rate and maximum capacity of PBE1 were 4.4 and 2.5 times higher than those of PB, respectively, due to the dual efficacy of accelerated kinetic and reinforced coordination. This study systematically analyzes the pivotal role of pore and electronic structure modulation in adsorption kinetic and affinity, which provides a novel strategy for PtII targeted recovery.

Phase Electronic Structure Tuning via Pt, P-Doped Ni4 Mo-Implanted Ti4 O7 for Highly Efficient Water Splitting and Mg/Seawater Batteries.

Fine-tuning nanoscale structures, morphologies, and electronic states are crucial for creating efficient water-splitting electrocatalysts. In this study, a method for electronic structure engineering to enhance overall water splitting in a corrosion-resistant electrocatalyst matrix by integrating Pt, P dual-doped Ni4 Mo electrocatalysts onto a Ti4 O7 nanorod grown on carbon cloth (Pt, P-Ni4 Mo-Ti4 O7 /CC) is introduced. By optimizing platinum and phosphorus concentrations to 1.18% and 2.42%, respectively, low overpotentials are achieved remarkably: 24mV at 10mA cm-2 for the hydrogen evolution reaction and 290mV at 20mA cm-2 for the oxygen evolution reaction in 1.0m KOH. These values approach or surpass those of benchmark Pt-C and IrO2 catalysts. Additionally, the Pt, P-Ni4 Mo-Ti4 O7 /CC bifunctional electrocatalyst displays low cell potentials across various mediums, maintaining excellent current retention (96% stability after 40 h in mimic seawater at 20mA cm-2 ) and demonstrating strong corrosion resistance and suitability for seawater electrolysis. As a cathode in magnesium/seawater batteries, it achieves a power density of 7.2mW cm-2 and maintains stability for 100 h. Density functional theory simulations confirm that P, Pt doping-assisted electronic structure modifications augment electrical conductivity and active sites in the hybrid electrocatalysts.

Unravelling the Factors Influencing Halide Perovskite Based Switchable Photovoltaics

AbstractLead halide perovskites have revolutionized the field of optoelectronics (such as photovoltaics and light emitting diodes) demonstrating extraordinary material properties despite being formed at low temperatures. However, ion migration in the bulk or at the interfaces results in stability issues especially in devices where metal electrodes directly interface with the perovskite film. Utilizing the switchable photovoltaic phenomenon (SPV) in halide perovskites as a measure of ion migration and electrochemical reactions within them, Cs0.05MA0.15FA0.70PbI2.5Br0.5 triple cation perovskite, widely used in photovoltaics is evaluated. The various factors determining the SPV, including electric field magnitudes, type of metal contacts, Illumination conditions, and temperature is systematically measured. This study reveals the roles of electrode work functions and reactivities on ion migration and local electronic structure modulation. ITO electrodes demonstrated the highest open‐circuit voltage (Voc) about 0.85 V while Ag electrodes developed conductive filaments. However, the Voc distribution for Ti and Cr electrodes shows a more pronounced linear correlation with the poling electric field strength. Insights from this lateral design are directly relevant to transistor and memristor architectures and offer inputs into the design of perovskite‐based photovoltaic/optoelectronic devices.