The optimized Fenton-like activity of Fe single-atom sites by Fe atomic clusters-mediated electronic configuration modulation.

The performance optimization of isolated atomically dispersed metal active sites is critical but challenging. Here, TiO2@Fe species-N-C catalysts with Fe atomic clusters (ACs) and satellite Fe-N4 active sites were fabricated to initiate peroxymonosulfate (PMS) oxidation reaction. The AC-induced charge redistribution of single atoms (SAs) was verified, thus strengthening the interaction between SAs and PMS. In detail, the incorporation of ACs optimized the HSO5- oxidation and SO5·- desorption steps, accelerating the reaction progress. As a result, the Vis/TiFeAS/PMS system rapidly eliminated 90.81% of 45 mg/L tetracycline (TC) in 10 min. The reaction process characterization suggested that PMS as an electron donor would transfer electron to Fe species in TiFeAS, generating 1O2. Subsequently, the hVB+ can induce the generation of electron-deficient Fe species, promoting the reaction circulation. This work provides a strategy to construct catalysts with multiple atom assembly-enabled composite active sites for high-efficiency PMS-based advanced oxidation processes (AOPs).

Lattice Strain and Charge Redistribution of Pt Cluster/Ir Metallene Heterostructure for Ethylene Glycol to Glycolic Acid Conversion Coupled with Hydrogen Production.

Upgrading overall water splitting (OWS) system and developing high-performance electrocatalysts is an attractive way to the improve efficiency and reduce the consumption of hydrogen (H2 ) production from electrolyzed water. Here, a Pt cluster/Ir metallene heterojunction structure (Pt/Ir hetero-metallene) with a unique Pt/Ir interface is reported for the conversion of ethylene glycol (EG) to glycolic acid (GA) coupled with H2 production. With the assistance of ethylene glycol oxidation (EGOR), the Pt/Ir||Pt/Ir hetero-metallene two-electrode water electrolysis system exhibits a lower cell voltage of 0.36 V at 10 mA cm-2 . Furthermore, the Faradaic efficiency of EG to GA is as high as 87%. The excellent performance of this new heterostructure arise from the charge redistribution and strain effects induced by Pt-Ir interactions between the heterogeneous interfaces, as well as the larger specific surface area and more active sites due to the metallene structure.

Regulation Dipole Moments of N-Doped Graphene Coordinated with FePc Toward Highly Efficient Microwave Absorption Performance in C Band.

The development of composites with highly efficient microwave absorption (MA) performance deeply depends on polarization loss, which can be induced by charge redistribution. Considering the fact that polarization centers can be easily obtained in graphene, herein, iron phthalocyanine (FePc) is used as polarization site to coordinate with nitrogen-doped graphene (FePc/N-rGO) to optimize MA performance comprehensively. The factors influencing MA properties focus on the interaction between FePc and N-rGO, and the change of dipole moments. The density functional theory (DFT) results demonstrated that FePc has strong interaction with N defect sites in graphene. The charge loss for FePc and charge accumulation for N-rGO occurred, leading to great increase of dipole moment, and the increased dipole moment can be acted as a descriptor to evaluate the enhanced polarization loss. Due to high charge redistribution capacity of N defect sites and FePc polarization centers, the FePc/N-rGO showed excellent MA properties in C band, and the minimum reflection loss value can reach -49.3 dB at 5.4 GHz with thickness of 3.8 mm. In addition, the fabric loaded with FePc/N-rGO showed good heat dissipation property. This work opens the door to the development of MA performance bound to polarization site with dipole moment.

Superconductivity in an Orbital-Reoriented SnAs Square Lattice: A Case Study of Li0.6 Sn2 As2 and NaSnAs.

Searching for functional square lattices in layered superconductor systems offers an explicit clue to modify the electron behavior and find exotic properties. The trigonal SnAs3 structural units in SnAs-based systems are relatively conformable to distortion, which provides the possibility to achieve structurally topological transformation and higher superconducting transition temperatures. In the present work, the functional As square lattice was realized and activated in Li0.6 Sn2 As2 and NaSnAs through a topotactic structural transformation of trigonal SnAs3 to square SnAs4 under pressure, resulting in a record-high Tc among all synthesized SnAs-based compounds. Meanwhile, the conductive channel transfers from the out-of-plane pz orbital to the in-plane px +py orbitals, facilitating electron hopping within the square 2D lattice and boosting the superconductivity. The reorientation of p-orbital following a directed local structure transformation provides an effective strategy to modify layered superconducting systems.

A Double Atomic-Tuned RuBi SAA/Bi@OG Nanostructure with Optimum Charge Redistribution for Efficient Hydrogen Evolution.

Charge redistribution on surface of Ru nanoparticle can significantly affect electrocatalytic HER activity. Herein, a double atomic-tuned RuBi SAA/Bi@OG nanostructure that features RuBi single-atom alloy nanoparticle supported by Bi-O single-site-doped graphene was successfully developed by one-step pyrolysis method. The alloyed Bi single atom and adjacent Bi-O single site in RuBi SAA/Bi@OG can synergistically manipulate electron transfer on Ru surface leading to optimum charge redistribution. Thus, the resulting RuBi SAA/Bi@OG exhibits superior alkaline HER activity. Its mass activity is up to 65000 mA mg-1 at an overpotential of 150 mV, which is 72.2 times as much as that of commercial Pt/C. DFT calculations reveal that the RuBi SAA/Bi@OG possesses the optimum charge redistribution, which is most beneficial to strengthen adsorption of water and weaken hydrogen-adsorption free energy in HER process. This double atomic-tuned strategy on surface charge redistribution of Ru nanoparticle opens a new way to develop highly efficient electrocatalysts.

Multistage Electron Distribution Engineering of Iridium Oxide by Codoping W and Sn for Enhanced Acidic Water Oxidation Electrocatalysis.

Developing efficient and robust anodic electrocatalysts to implement the proton-exchange membrane (PEM) electrolyzer is critical for hydrogen generation. Nevertheless, the only known applicable anode catalyst IrOx in PEM electrolyzers still requires high overpotential due to the weak binding energy between oxygen intermediates and active sites, limiting its wide applications. Herein, a ternary Ir0.7 W0.2 Sn0.1 Ox nanocatalyst synthesized through a sol-gel strategy, exhibits a low overpotential of 236 mV (10 mA cm-2 geo ) for thoxygen evolution reaction (OER), accompanied with robust durability over 220 h at 1 A cm-2 geo in 0.5 m H2 SO4 . Moreover, the optimized Ir0.7 W0.2 Sn0.1 Ox delivers a prominent mass activity of 722.7 A g-1 Ir at 1.53 V (vs RHE), which is around 34 times higher compared with that of IrOx . The mircrostructural analyses reveal that codoping of W and Sn stabilizes Ir with a valence state lower than 4+ through multistage charge redistribution, avoiding the overoxidation of Ir above 1.6 V versus RHE and enhancing the acidic OER performance. Additionally, density functional theory calculations reveal that codoping of W and Sn moves the d band center of Ir to the Fermi level, thus enhancing the binding energies of oxygen intermediates with Ir sites and decreasing the energy barrier toward acidic OER.

Insight into the stacking and the species-ordering dependences of interlayer bonding in SiC/GeC polar heterostructures.

Two-dimensional (2D) polar materials experience an in-plane charge transfer between different elements due to their electron negativities. When they form vertical heterostructures, the electrostatic force triggered by such charge transfer plays an important role in the interlayer bonding beyond van der Waals (vdW) interaction. Our comprehensive first principle study on the structural stability of the 2D SiC/GeC hybrid bilayer heterostructure has found that the electrostatic interlayer interaction can induce theπ-πorbital hybridization between adjacent layers under different stacking and out-of-plane species ordering, with strong hybridization in the cases of Si-C and C-Ge species orderings but weak hybridization in the case of the C-C ordering. In particular, the attractive electrostatic interlayer interaction in the cases of Si-C and C-Ge species orderings mainly controls the equilibrium interlayer distance and the vdW interaction makes the system attain a lower binding energy. On the contrary, the vdW interaction mostly controls the equilibrium interlayer distance in the case of the C-C species ordering and the repulsive electrostatic interlayer force has less effect. Interesting finding is that the band structure of the SiC/GeC hybrid bilayer is sensitive to the layer-layer stacking and the out-of-plane species ordering. An indirect band gap of 2.76 eV (or 2.48 eV) was found under the AA stacking with Si-C ordering (or under the AB stacking with C-C ordering). While a direct band gap of 2.00-2.88 eV was found under other stacking and species orderings, demonstrating its band gap tunable feature. Furthermore, there is a charge redistribution in the interfacial region leading to a built-in electric field. Such field will separate the photo-generated charge carriers in different layers and is expected to reduce the probability of carrier recombination, and eventually give rise to the electron tunneling between layers.

In-Situ Surface Reconstruction of InN Nanosheets for Efficient CO2 Electroreduction into Formate.

Probing and understanding the intrinsic active sites of electrocatalysts is crucial to unravel the underlying mechanism of CO2 electroreduction and provide a prospective for the rational design of high-performance electrocatalysts. However, their structure-activity relationships are not straightforward because electrocatalysts might reconstruct under realistic working conditions. Herein, we employ in-situ measurements to unveil the intrinsic origin of the InN nanosheets which served as an efficient electrocatalyst for CO2 reduction with a high faradaic efficiency of 95% for carbonaceous product. During the CO2 electroreduction, InN nanosheets reconstructed to form the In-rich surface. Density functional theory calculations revealed that the reconstruction of InN led to the redistribution of surface charge that significantly promoted the adsorption of HCOO* intermediates and thus benefited the formation of formate toward CO2 electroreduction. This work establishes a fundamental understanding on the mechanism associated with self-reconstruction of heterogeneous catalysts toward CO2 electroreduction.

Charge transfer enhanced magnetic correlations in type-II multiferroic Co3TeO6.

Magnetic structure of the Co ions in monoclinic Co3TeO6 in the antiferroelectric state at 16 K has been determined by neutron powder together with single-crystal diffractions. The indices of the magnetic reflections that appear at the incommensurate positions were determined by diffractions from a single crystal, which allow to uniquely identify the magnetic modulation vector. There are two crystallographically distinct Co layers. Magnetic incommensurability appears in the Co spins in the layers comprising zig-zag chains, with a magnetic modulation vector of (0.357, 0.103, 0.121) at 3 K but changes to (0.4439, 0, 0.137) at 16 K, while the Co ions in the honeycomb webs form a collinear antiferromagnetic structure. Thermal reduction rate of the Co moments in the honeycomb webs was found to be much smaller than those in the zigzag chains. Shifting of large amounts of electronic charge into the Co─O bonds in the honeycomb webs on warming is used to understand the behavior.

On-Surface Decarboxylation Coupling Facilitated by Lock-to-Unlock Variation of Molecules upon the Reaction.

On-surface synthesis (OSS) involving relatively high energy barriers remains challenging due to a typical dilemma: firm molecular anchor is required to prevent molecular desorption upon the reaction, whereas sufficient lateral mobility is crucial for subsequent coupling and assembly. By locking the molecular precursors on the substrate then unlocking them during the reaction, we present a strategy to address this challenge. High-yield synthesis based on well-defined decarboxylation, intermediate transition, and hexamerization is demonstrated, resulting in an extended and ordered network exclusively composed of the newly synthesized macrocyclic compound. Thanks to the steric hindrance of its maleimide group, we attain a preferential selection of the coupling. This work unlocks a promising path to enrich the reaction types and improve the coupling selectivity hence the structual homogeneity of the final product for OSS.

Additional Lithium Storage on Dynamic Electrode Surface by Charge Redistribution in Inactive Ru Metal.

Beyond a traditional view that metal nanoparticles formed upon electrochemical reaction are inactive against lithium, recently their electrochemical participations are manifested and elucidated as catalytic and interfacial effects. Here, ruthenium metal composed of ≈5 nm nanoparticles is prepared and the pure ruthenium as a lithium-ion battery anode for complete understanding on anomalous lithium storage reaction mechanism is designed. In particular, the pure metal electrode is intended for eliminating the electrochemical reaction-derived Li2 O phase accompanied by catalytic Li2 O decomposition and the interfacial lithium storage at Ru/Li2 O phase boundary, and thereby focusing on the ruthenium itself in exploring its electrochemical reactivity. Intriguingly, unusual lithium storage not involving redox reactions with electron transfer but leading to lattice expansion is identified in the ruthenium electrode. Size-dependent charge redistribution at surface enables additional lithium adsorption to occur on the inactive but more environmentally sensitive nanoparticles, providing innovative insight into dynamic electrode environments in rechargeable lithium chemistry.

Direct Observation of a Li-Ionic Space-Charge Layer Formed at an Electrode/Solid-Electrolyte Interface.

When two different materials come into contact, mobile carriers redistribute at the interface according to their potential difference. Such a charge redistribution is also expected at the interface between electrodes and solid electrolytes. The redistributed ions significantly affect the ion conduction through the interface. Thus, it is essential to determine the actual distribution of the ionic carriers and their potential to improve ion conduction. We succeeded in visualizing the ionic and potential profiles in the charge redistribution layer, or space-charge layer (SCL), formed at the interface between a Cu electrode and Li-conductive solid electrolyte using phase-shifting electron holography and spatially resolved electron energy-loss spectroscopy. These electron microscopy techniques clearly showed the Li-ionic SCL, which dropped by 1.3 V within a distance of 10 nm from the interface. These techniques could contribute to the development of next-generation electrochemical devices.

Electrophoretic mobility of oil droplets in electrolyte and surfactant solutions.

Electrophoretic mobility of oil droplets of micron sizes in PBS and ionic surfactant solutions was measured in this paper. The experimental results show that, in addition to the applied electric field, the speed and the direction of electrophoretic motion of oil droplets depend on the surfactant concentration and on if the droplet is in negatively charged SDS solutions or in positively charged hexadecyltrimethylammonium bromide (CTAB) solutions. The absolute value of the electrophoretic mobility increases with increased surfactant concentration before the surfactant concentration reaches to the CMC. It was also found that there are two vortices around the oil droplet under the applied electric field. The size of the vortices changes with the surfactant and with the electric field. The vortices around the droplet directly affect the drag of the flow field to the droplet motion and should be considered in the studies of electrophoretic mobility of oil droplets. The existence of the vortices will also influence the determination and the interpretation of the zeta potential of the oil droplets based on the measured mobility data.

Charge Redistribution in High-Entropy Perovskite Oxide Porous Nanotubes Boosts Nitrate Electroreduction to Ammonia.

High-entropy perovskite oxides are promising materials in the field of electrocatalysis due to their advantages such as large spatial composition regulation, entropy effects, and tunable material properties. However, the preparation of high-entropy perovskite oxides with stable and controllable structures still remains challenging. Herein, we fabricated a series of high-entropy perovskite oxide porous nanotubes (PNTs) by electrospinning as efficient electrocatalysts for the nitrate reduction reaction (NO3RR). We further revealed that the different diffusion and decomposition behaviors of metal ions and polymers during the calcination process are the key to the formation of high-entropy perovskite oxide PNTs. Especially, LaSrNiCoMnFeCuO3 PNTs show excellent performance of the NO3RR, achieving the maximum NH3 Faradaic efficiency of almost 100%, yield rate of 1657.5 µg h-1 mgcat.-1, and durable stability after successive cycling, being one of the best electrocatalysts for the NO3RR. The mechanism studies show that the charge redistribution induced by the multisite synergistic effect and abundant unsaturated sites in the high-entropy perovskite oxide PNTs favors the adsorption of NO3- and key intermediates and reduces the catalytic energy barrier, thus further achieving high NO3- conversion efficiency.

Heterogeneous NASICON-Type Cathode With Reversible Multielectron Reaction for High-Performance Sodium-Ion Batteries.

Na superionic conductor (NASICON)-structured compounds demonstrate great application potential by their robust framework and compositional diversity. However, they are blamed for the mediocre energy density, and achieving both multielectron reaction and good cycling stability simultaneously is challenging. Herein, a novel heterogeneous Na4Fe3(PO4)2(P2O7)/Na2VTi(PO4)3 (NFPP/NVTP) material with stable multielectron reaction is constructed by spray drying technology. The mutual promotion effect of intergrowth structures effectively improves the purity and the crystallization of NFPP/NVTP during the fabrication process, which is beneficial to the high capacity and cycling stability. As a result, the optimized NFPP/NVTP demonstrates a high reversible capacity of 155.3 mAh g-1 at 20 mA g-1 and outstanding cycling stability with 82.9% capacity retention over 2500 cycles at 1 A g-1, which are much superior to those of NFPP and NVTP individually. Even in full cell configuration, the energy density remains high at ≈380 Wh kg-1 based on the cathode mass. The high capacity of NFPP/NVTP is also attributed to the successive reduction/oxidation mechanism involving the introduction of Ti3+ and interfacial charge redistribution effect between the heterogeneous phases, which greatly improve the electronic and ionic conductivity. Moreover, high reversible structural evolution during the multisodium storage process further guarantees excellent cycling stability.

Quantum States Induced by Strong Interface Coupling in a 2D VSe2/Bi2Se3 Heterostructure.

We have successfully fabricated single-layer (SL) 1T-VSe2/Bi2Se3 heterostructures using molecular beam epitaxy (MBE), which exhibits uniform moiré patterns on the heterostructure surface. Scanning tunneling microscopy/spectroscopy (STM/STS) reveals a notable quantum state near the Fermi energy, robust across the entire moiré lattice. This quantum state peak shifts slightly across different domain ranges, suggesting an elastic strain dependence in SL VSe2, confirmed by geometric phase analysis (GPA) simulations. Density functional theory (DFT) calculations indicate that the enhanced quantum state results from charge redistribution between the substrate and the epifilm with the orbitals of Se atoms in the deformed VSe2 playing a dominant role.

Dopant-Induced Charge Redistribution on the 3D Sponge-like Hierarchical Structure of Quaternary Metal Phosphides Nanosheet Arrays Derived from Metal-Organic Frameworks for Natural Seawater Splitting.

Dopant-induced electron redistribution on transition metal-based materials has long been considered an emerging new electrocatalyst that is expected to replace noble-metal-based electrocatalysts in natural seawater electrolysis; however, their practical applications remain extremely daunting due to their sluggish kinetics in natural seawater. In this work, we developed a facile strategy to synthesize the 3D sponge-like hierarchical structure of Ru-doped NiCoFeP nanosheet arrays derived from metal-organic frameworks with remarkable hydrogen evolution reaction (HER) performance in natural seawater. Based on experimental results and density functional theory calculations, Ru-doping-induced charge redistribution on the surface of metal active sites has been found, which can significantly enhance the HER activity. As a result, the 3D sponge-like hierarchical structure of Ru-NiCoFeP nanosheet arrays achieves low overpotentials of 52, 149, and 216 mV at 10, 100, and 500 mA cm-2 in freshwater alkaline, respectively. Notably, the electrocatalytic activity of the Ru-NiCoFeP electrocatalyst in simulated alkaline seawater and natural alkaline seawater is nearly the same as that in freshwater alkaline. This electrocatalyst exhibits superior catalytic properties with outstanding stability under a high current density of 85 mA cm-2 for more than 100 h in natural seawater, which outperforms state-of-the-art 20% Pt/C at high current density. Our work provides valuable guidelines for developing a low-cost and high-efficiency electrocatalyst for natural seawater splitting.

Anchoring covalent organic polymers on supports with tunable functional groups boosting the oxygen reduction performance under pH-universal conditions.

Iron phthalocyanine (FePc) is an attractive nonprecious metal candidate for electrocatalytic oxygen reduction reaction (ORR). However, its low catalytic performance under acidic and neutral conditions limits its practical application. Herein, the FePc-based covalent organic polymers (COPFePc) polymerized in situ on the functionalized multiwalled carbon nanotubes (R-MWCNT) containing different electron-withdrawing or electron-donating groups (COPFePc/R-MWCNT, R = COOH, OH or NH2) were synthesized for ORR. Among them, COPFePc/COOH-MWCNT exhibited the best ORR performance under pH-universal conditions (acidic, neutral, and alkaline). Density-functional theory (DFT) calculations demonstrate that the electron-withdrawing or electron-donating effect of the functional groups in COPFePc/R-MWCNT causes charge redistribution of the active center Fe. The COOH functional group with an electron-withdrawing ability shifts the d-band center of Fe away from the Fermi energy level and reduces the binding strength of oxygen-containing intermediates, accelerating the ORR kinetics and optimizing the catalytic activity.

Tailored nitrogen-defect induced by diels-alder reaction for enhanced electrochemical hydrogen evolution reaction.

Electrocatalytic water splitting in an alkaline medium is recognized as the promising technology to sustainably generate clean hydrogen energy via hydrogen evolution reaction (HER), while the sluggish water dissociation and subsequent *H adsorption steps greatly retarded the reaction kinetics and efficiency of the overall hydrogen evolution process. Whilst nitrogen (N)-doped carbon-based materials are attractive candidates for promoting HER activity, the facile fabrication and gaining a deeper insight into the electrocatalytic mechanism are still challenging. Herein, inspired by the Diels-Alder reaction, we precisely tailored six-membered pyridinic N and five-membered pyrrolic N sites at the edge of the carbon substrates. Comprehensive analysis validates that the participation of pyridinic N (electron-withdrawing) and pyrrolic N (electron-releasing) will induce the charge rearrangements, and further generate local electrophilic and nucleophilic domains in adjacent carbon rings, which guarantees the occurrence of water dissociation to generate protons and the subsequent adsorption of *H intermediates through electrostatic interactions, thereby facilitating the overall reaction kinetics. To this end, the optimal NC-ZnCl2-25 % electrocatalysts present excellent alkaline HER activity (η10 = 45 mV, Tafel slop of 37.7 mV dec-1) superior to commercial Pt/C.

Defect-induced charge redistribution of MoO3-x nanometric wires for photocatalytic ammonia synthesis.

Photocatalytic ammonia synthesis technology has become one of the effective methods to replace the Haber method for nitrogen fixation in the future for its low energy consumption and green environment. However, limited by the weak adsorption/activation ability of N2 molecules at the photocatalyst interface, the efficient nitrogen fixation still remains a daunting job. Defect-induced charge redistribution as a catalytic site for N2 molecules is the most prominent strategy to enhance the adsorption/activation of N2 molecules at the interface of catalysts. In this study, MoO3-x nanowires containing asymmetric defects were prepared by a one-step hydrothermal method via using glycine as a defect inducer. It is shown that at the atomic scale, the defect-induced charge reconfiguration can significantly improve the nitrogen adsorption and activation capacity and enhance the nitrogen fixation capacity; at the nanoscale, the charge redistribution induced by asymmetric defects effectively improved the photogenerated charge separation. Given the charge redistribution on the atomic and nanoscale of MoO3-x nanowires, the optimal nitrogen fixation rate of MoO3-x reached 200.35 µmol g-1h-1.