Penta-graphene: A new carbon allotrope

A 2D metastable carbon allotrope, penta-graphene, composed entirely of carbon pentagons and resembling the Cairo pentagonal tiling, is proposed. State-of-the-art theoretical calculations confirm that the new carbon polymorph is not only dynamically and mechanically stable, but also can withstand temperatures as high as 1000 K. Due to its unique atomic configuration, penta-graphene has an unusual negative Poisson's ratio and ultrahigh ideal strength that can even outperform graphene. Furthermore, unlike graphene that needs to be functionalized for opening a band gap, penta-graphene possesses an intrinsic quasi-direct band gap as large as 3.25 eV, close to that of ZnO and GaN. Equally important, penta-graphene can be exfoliated from T12-carbon. When rolled up, it can form pentagon-based nanotubes which are semiconducting, regardless of their chirality. When stacked in different patterns, stable 3D twin structures of T12-carbon are generated with band gaps even larger than that of T12-carbon. The versatility of penta-graphene and its derivatives are expected to have broad applications in nanoelectronics and nanomechanics.

Fabrication of multiple heterojunctions with tunable visible-light-active photocatalytic reactivity in BiOBr-BiOI full-range composites based on microstructure modulation and band structures

The fabrication of multiple heterojunctions with tunable photocatalytic reactivity in full-range BiOBr-BiOI composites based on microstructure modulation and band structures is demonstrated. The multiple heterojunctions are constructed by precipitation at room temperature and characterized systematically. Photocatalytic experiments indicate that there are two types of heterostructures with distinct photocatalytic mechanisms, both of which can greatly enhance the visible-light photocatalytic performance for the decomposition of organic pollutants and generation of photocurrent. The large separation and inhibited recombination of electron-hole pairs rendered by the heterostructures are confirmed by electrochemical impedance spectra (EIS) and photoluminescence (PL). Reactive species trapping, nitroblue tetrazolium (NBT, detection agent of (•)O2(-)) transformation, and terephthalic acid photoluminescence (TA-PL) experiments verify the charge-transfer mechanism derived from the two types of heterostructures, as well as different enhancements of the photocatalytic activity. This article provides insights into heterostructure photocatalysis and describes a novel way to design and fabricate high-performance semiconductor composites.

High-Electron-Mobility and Air-Stable 2D Layered PtSe2 FETs

The electrical and optical measurements, in combination with density functional theory calculations, show distinct layer-dependent semiconductor-to-semimetal evolution of 2D layered PtSe₂ . The high room-temperature electron mobility and near-infrared photo-response, together with much better air-stability, make PtSe₂ a versatile electronic 2D layered material.

Perovskite-based hybrid solar cells exceeding 10% efficiency with high reproducibility using a thin film sandwich approach

Organometal halide perovskites have tremendous potential as light absorbers for photovoltaic applications. In this work we demonstrate hybrid solar cells based on the mixed perovskite CH3 NH3 PbI2 Cl in a thin film sandwich structure, with unprecedented reproducibility and generating efficiencies up to 10.8%. The successfulness of our approach is corroborated by the experimental electronic structure determination of this perovskite.

Organic-to-inorganic structural chirality transfer in a 2D hybrid perovskite and impact on Rashba-Dresselhaus spin-orbit coupling

Translation of chirality and asymmetry across structural motifs and length scales plays a fundamental role in nature, enabling unique functionalities in contexts ranging from biological systems to synthetic materials. Here, we introduce a structural chirality transfer across the organic-inorganic interface in two-dimensional hybrid perovskites using appropriate chiral organic cations. The preferred molecular configuration of the chiral spacer cations, R-(+)- or S-(-)-1-(1-naphthyl)ethylammonium and their asymmetric hydrogen-bonding interactions with lead bromide-based layers cause symmetry-breaking helical distortions in the inorganic layers, otherwise absent when employing a racemic mixture of organic spacers. First-principles modeling predicts a substantial bulk Rashba-Dresselhaus spin-splitting in the inorganic-derived conduction band with opposite spin textures between R- and S-hybrids due to the broken inversion symmetry and strong spin-orbit coupling. The ability to break symmetry using chirality transfer from one structural unit to another provides a synthetic design paradigm for emergent properties, including Rashba-Dresselhaus spin-polarization for hybrid perovskite spintronics and related applications.

Recent advances in phenoxyl radical complexes of salen-type ligands as mixed-valent galactose oxidase models

The interplay between redox-active transition metal ions and redox-active ligands in metalloenzyme sites is an area of considerable research interest. Galactose oxidase (GO) is the archetypical example, catalyzing the aerobic oxidation of primary alcohols to aldehydes via two one-electron cofactors: a copper atom and a cysteine-modified tyrosine residue. The electronic structure of the oxidized form of the enzyme (GO(ox)) has been investigated extensively through small molecule analogues including metal-salen phenoxyl radical complexes. Similar to GO(ox), one-electron oxidized metal-salen complexes are mixed-valent species, in which molecular orbitals (MOs) with predominantly phenolate and phenoxyl π-character act as redox-active centers bridged by mixing with metal d-orbitals. A detailed evaluation of the electronic distribution in these odd electron species using a variety of spectroscopic, electrochemical, and theoretical techniques has led to keen insights into the electronic structure of GO(ox).

Synthesis and characterization of a uranium(II) monoarene complex supported by δ backbonding

The low-temperature (<-35 °C) reduction of the trivalent uranium monoarene complex [{((Ad,Me) ArO)3 mes}U] (1), with potassium spheres in the presence of a slight excess of 2.2.2-cryptand, affords the quantitative conversion of 1 into the uranium(II) monoarene complex [K(2.2.2-crypt)][(((Ad,Me) ArO)3 mes)U] (1-K). The molecular and electronic structure of 1-K was established experimentally by single-crystal X-ray diffraction, variable-temperature (1) H NMR and X-band EPR spectroscopy, solution-state and solid-state magnetism studies, and optical absorption spectroscopy. The electronic structure of the complex was further investigated by DFT calculations. The complete body of evidence confirms that 1-K is a uranium(II) monoarene complex with a 5f (4) electronic configuration supported by δ backbonding and that the nearly reversible, room-temperature reduction observed for 1 at -2.495 V vs. Fc/Fc(+) is principally metal-centered.

Ferroelectric Domain Wall Induced Band Gap Reduction and Charge Separation in Organometal Halide Perovskites

Organometal halide perovskites have been intensely studied in the past 5 years, inspired by their certified high photovoltaic power conversion efficiency. Some of these materials are room-temperature ferroelectrics. The presence of switchable ferroelectric domains in methylammonium lead triiodide, CH3NH3PbI3, has recently been observed via piezoresponse force microscopy. Here, we focus on the structural and electronic properties of ferroelectric domain walls in CH3NH3PbX3 (X = Cl, Br, I). We find that organometal halide perovskites can form both charged and uncharged domain walls due to the flexible orientational order of the organic molecules. The electronic band gaps for domain structures possessing 180 and 90° walls are estimated with density functional theory. It is found that the presence of charged domain walls will significantly reduce the band gap by 20-40%, while the presence of uncharged domain walls has no substantial impact on the band gap. We demonstrate that charged domain walls can serve as segregated channels for the motions of charge carriers. These results highlight the importance of ferroelectric domain walls in hybrid perovskites for photovoltaic applications and suggest a possible avenue for device optimization through domain patterning.

Recent Advances in Atomic Metal Doping of Carbon-based Nanomaterials for Energy Conversion

Nanostructured metal-contained catalysts are one of the most widely used types of catalysts applied to facilitate some of sluggish electrochemical reactions. However, the high activity of these catalysts cannot be sustained over a variety of pH ranges. In an effort to develop highly active and stable metal-contained catalysts, various approaches have been pursued with an emphasis on metal particle size reduction and doping on carbon-based supports. These techniques enhances the metal-support interactions, originating from the chemical bonding effect between the metal dopants and carbon support and the associated interface, as well as the charge transfer between the atomic metal species and carbon framework. This provides an opportunity to tune the well-defined metal active centers and optimize their activity, selectivity and stability of this type of (electro)catalyst. Herein, recent advances in synthesis strategies, characterization and catalytic performance of single atom metal dopants on carbon-based nanomaterials are highlighted with attempts to understand the electronic structure and spatial arrangement of individual atoms as well as their interaction with the supports. Applications of these new materials in a wide range of potential electrocatalytic processes in renewable energy conversion systems are also discussed with emphasis on future directions in this active field of research.

Defect-Tailoring Mediated Electron-Hole Separation in Single-Unit-Cell Bi3 O4 Br Nanosheets for Boosting Photocatalytic Hydrogen Evolution and Nitrogen Fixation

Solar photocatalysis is a potential solution to satisfying energy demand and its resulting environmental impact. However, the low electron-hole separation efficiency in semiconductors has slowed the development of this technology. The effect of defects on electron-hole separation is not always clear. A model atomically thin structure of single-unit-cell Bi₃ O₄ Br nanosheets with surface defects is proposed to boost photocatalytic efficiency by simultaneously promoting bulk- and surface-charge separation. Defect-rich single-unit-cell Bi₃ O₄ Br displays 4.9 and 30.9 times enhanced photocatalytic hydrogen evolution and nitrogen fixation activity, respectively, than bulk Bi₃ O₄ Br. After the preparation of single-unit-cell structure, the bismuth defects are controlled to tune the oxygen defects. Benefiting from the unique single-unit-cell architecture and defects, the local atomic arrangement and electronic structure are tuned so as to greatly increase the charge separation efficiency and subsequently boost photocatalytic activity. This strategy provides an accessible pathway for next-generation photocatalysts.

Effect of Copper Doping on Electronic Structure, Geometric Structure, and Stability of Thiolate-Protected Au25 Nanoclusters

Several recent studies have attempted to impart [Au25(SR)18](-) with new properties by doping with foreign atoms. In this study, we studied the effect of copper doping on the electronic structure, geometric structure, and stability of [Au25(SR)18](-) with the aim of investigating the effect of foreign atom doping of [Au25(SR)18](-). CunAu25-n(SC2H4Ph)18 was synthesized by reducing complexes formed by the reaction between metal salts (copper and gold salts) and PhC2H4SH with NaBH4. Mass analysis revealed that the products contained CunAu25-n(SC2H4Ph)18 (n = 1-5) in high purity. Experimental and theoretical analysis of the synthesized clusters revealed that copper doping alters the optical properties and redox potentials of the cluster, greatly distorts its geometric structure, and reduces the cluster stability in solution. These findings are expected to be useful for developing design guidelines for functionalizing [Au25(SR)18](-) through doping with foreign atoms.

K- and L-edge X-ray Absorption Spectroscopy (XAS) and Resonant Inelastic X-ray Scattering (RIXS) Determination of Differential Orbital Covalency (DOC) of Transition Metal Sites

Continual advancements in the development of synchrotron radiation sources have resulted in X-ray based spectroscopic techniques capable of probing the electronic and structural properties of numerous systems. This review gives an overview of the application of metal K-edge and L-edge X-ray absorption spectroscopy (XAS), as well as K resonant inelastic X-ray scattering (RIXS), to the study of electronic structure in transition metal sites with emphasis on experimentally quantifying 3d orbital covalency. The specific sensitivities of K-edge XAS, L-edge XAS, and RIXS are discussed emphasizing the complementary nature of the methods. L-edge XAS and RIXS are sensitive to mixing between 3d orbitals and ligand valence orbitals, and to the differential orbital covalency (DOC), that is, the difference in the covalencies for different symmetry sets of the d orbitals. Both L-edge XAS and RIXS are highly sensitive to and enable separation of and donor bonding and back bonding contributions to bonding. Applying ligand field multiplet simulations, including charge transfer via valence bond configuration interactions, DOC can be obtained for direct comparison with density functional theory calculations and to understand chemical trends. The application of RIXS as a probe of frontier molecular orbitals in a heme enzyme demonstrates the potential of this method for the study of metal sites in highly covalent coordination sites in bioinorganic chemistry.

Interfacial Electronic Structure Modulation of NiTe Nanoarrays with NiS Nanodots Facilitates Electrocatalytic Oxygen Evolution

Interface engineering has been recognized as one of the most promising strategies for regulating the physical and chemical properties of materials. However, constructing well-defined nanointerfaces with efficient oxygen evolution reaction (OER) still remains a challenge. Herein, cross columnar NiTe nanoarrays supported on nickel foam are prepared. Subsequently, NiTe/NiS nanointerfaces are constructed by an ion-exchange process. Importantly, the electrocatalytic performance for the OER can be facilitated by coupling NiTe and NiS. As a result, NiTe/NiS shows excellent OER activity with an ultralow overpotential of only 257 mV at a current density of 100 mA cm^-2 , and a Tafel slope of 49 mV dec^-1 in 1.0 m KOH. The calculated and experimental results reveal that the strong electron interaction on nanointerfaces induces electronic structure modulation, which optimizes the binding energy of *OOH intermediates, thus improving the OER performance.

Electronic Structure Reconfiguration toward Pyrite NiS2 via Engineered Heteroatom Defect Boosting Overall Water Splitting

Developing highly active and low-cost heterogeneous catalysts toward overall electrochemical water splitting is extremely desirable but still a challenge. Herein, we report pyrite NiS₂ nanosheets doped with vanadium heteroatoms as bifunctional electrode materials for both hydrogen- and oxygen-evolution reaction (HER and OER). Notably, the electronic structure reconfiguration of pyrite NiS₂ is observed from typical semiconductive characteristics to metallic characteristics by engineering vanadium (V) displacement defect, which is confirmed by both experimental temperature-dependent resistivity and theoretical density functional theory calculations. Furthermore, elaborate X-ray absorption spectroscopy measurements reveal that electronic structure reconfiguration of NiS₂ is rooted in electron transfer from doped V to Ni sites, consequently enabling Ni sites to gain more electrons. The metallic V-doped NiS₂ nanosheets exhibit extraordinary electrocatalytic performance with overpotentials of about 290 mV for OER and about 110 mV for HER at 10 mA cm^-2 with long-term stability in 1 M KOH solutions, representing one of the best non-noble-metal bifunctional electrocatalysts to date. This work provides insights into electronic structure engineering from well-designed atomic defect metal sulfide.

Co-Induced Electronic Optimization of Hierarchical NiFe LDH for Oxygen Evolution

Developing efficient and stable non-noble electrocatalysts for the oxygen evolution reaction (OER) remains challenging for practical applications. While nickel-iron layered double hydroxides (NiFe-LDH) are emerging as prominent candidates with promising OER activity, their catalytic performance is still restricted by the limited active sites, poor conductivity and durability. Herein, hierarchical nickel-iron-cobalt LDH nanosheets/carbon fibers (NiFeCo-LDH/CF) are synthesized through solvent-thermal treatment of ZIF-67/CF. Extended X-ray adsorption fine structure analyses reveal that the Co substitution can stabilize the Fe local coordination environment and facilitate the π-symmetry bonding orbital in NiFeCo-LDH/CF, thus modifying the electronic structures. Coupling with the structural advantages, including the largely exposed active surface sites and facilitated charge transfer pathway ensured by CF, the resultant NiFeCo-LDH/CF exhibits excellent OER activity with an overpotential of 249 mV at 10 mA cm^-1 as well as robust stability over 20 h.

Investigation of Catalytic Finite-Size-Effects of Platinum Metal Clusters

In this paper, we use density functional theory (DFT) calculations on highly parallel computing resources to study size-dependent changes in the chemical and electronic properties of platinum (Pt) for a number of fixed freestanding clusters ranging from 13 to 1415 atoms, or 0.7-3.5 nm in diameter. We find that the surface catalytic properties of the clusters converge to the single crystal limit for clusters with as few as 147 atoms (1.6 nm). Recently published results for gold (Au) clusters showed analogous convergence with size. However, this convergence happened at larger sizes, because the Au d-states do not contribute to the density of states around the Fermi-level, and the observed level fluctuations were not significantly damped until the cluster reached ca. 560 atoms (2.7 nm) in size.

Switchable S = 1/2 and J = 1/2 Rashba bands in ferroelectric halide perovskites

The Rashba effect is spin degeneracy lift originated from spin-orbit coupling under inversion symmetry breaking and has been intensively studied for spintronics applications. However, easily implementable methods and corresponding materials for directional controls of Rashba splitting are still lacking. Here, we propose organic-inorganic hybrid metal halide perovskites as 3D Rashba systems driven by bulk ferroelectricity. In these materials, it is shown that the helical direction of the angular momentum texture in the Rashba band can be controlled by external electric fields via ferroelectric switching. Our tight-binding analysis and first-principles calculations indicate that S = 1/2 and J = 1/2 Rashba bands directly coupled to ferroelectric polarization emerge at the valence and conduction band edges, respectively. The coexistence of two contrasting Rashba bands having different compositions of the spin and orbital angular momentum is a distinctive feature of these materials. With recent experimental evidence for the ferroelectric response, the halide perovskites will be, to our knowledge, the first practical realization of the ferroelectric-coupled Rashba effect, suggesting novel applications to spintronic devices.

Revised M06 density functional for main-group and transition-metal chemistry

We present a hybrid metageneralized-gradient-approximation functional, revM06, which is based on adding Hartree-Fock exchange to the revM06-L functional form. Compared with the original M06 suite of density functionals, the resulting revM06 functional has significantly improved across-the-board accuracy for both main-group and transition-metal chemistry. The revM06 functional improves on the M06-2X functional for main-group and transition-metal bond energies, atomic excitation energies, isomerization energies of large molecules, molecular structures, and both weakly and strongly correlated atomic and molecular data, and it shows a clear improvement over M06 and M06-2X for noncovalent interactions, including smoother potential curves for rare-gas dimers. The revM06 functional also predicts more accurate results than M06 and M06-2X for most of the outside-the-training-set test sets examined in this study. Therefore, the revM06 functional is well-suited for a broad range of chemical applications for both main-group and transition-metal elements.

Formal Estimation of Errors in Computed Absolute Interaction Energies of Protein-ligand Complexes

A largely unsolved problem in computational biochemistry is the accurate prediction of binding affinities of small ligands to protein receptors. We present a detailed analysis of the systematic and random errors present in computational methods through the use of error probability density functions, specifically for computed interaction energies between chemical fragments comprising a protein-ligand complex. An HIV-II protease crystal structure with a bound ligand (indinavir) was chosen as a model protein-ligand complex. The complex was decomposed into twenty-one (21) interacting fragment pairs, which were studied using a number of computational methods. The chemically accurate complete basis set coupled cluster theory (CCSD(T)/CBS) interaction energies were used as reference values to generate our error estimates. In our analysis we observed significant systematic and random errors in most methods, which was surprising especially for parameterized classical and semiempirical quantum mechanical calculations. After propagating these fragment-based error estimates over the entire protein-ligand complex, our total error estimates for many methods are large compared to the experimentally determined free energy of binding. Thus, we conclude that statistical error analysis is a necessary addition to any scoring function attempting to produce reliable binding affinity predictions.

Well-Dispersed Nickel- and Zinc-Tailored Electronic Structure of a Transition Metal Oxide for Highly Active Alkaline Hydrogen Evolution Reaction

The practical scale-up of renewable energy technologies will require catalysts that are more efficient and durable than present ones. This is, however, a formidable challenge that will demand a new capability to tailor the electronic structure. Here, an original electronic structure tailoring of CoO by Ni and Zn dual doping is reported. This changes it from an inert material into one that is highly active for the hydrogen evolution reaction (HER). Based on combined density functional theory calculations and cutting-edge characterizations, it is shown that dual Ni and Zn doping is responsible for a highly significant increase in HER activity of the host oxide. That is, the Ni dopants cluster around surface oxygen vacancy of the host oxide and provide an ideal electronic surface structure for hydrogen intermediate binding, while the Zn dopants distribute inside the host oxide and modulate the bulk electronic structure to boost electrical conduction. As a result, the dual-doped Ni, Zn CoO nanorods achieve current densities of 10 and 20 mA cm^-2 at overpotentials of, respectively, 53 and 79 mV. This outperforms reported state-of-the-art metal oxide, metal oxide/metal, metal sulfide, and metal phosphide catalysts.

Heteroanionic Materials by Design: Progress Toward Targeted Properties

The burgeoning field of anion engineering in oxide-based compounds aims to tune physical properties by incorporating additional anions of different size, electronegativity, and charge. For example, oxychalcogenides, oxynitrides, oxypnictides, and oxyhalides may display new or enhanced responses not readily predicted from or even absent in the simpler homoanionic (oxide) compounds because of their proximity to the ionocovalent-bonding boundary provided by contrasting polarizabilities of the anions. In addition, multiple anions allow heteroanionic materials to span a more complex atomic structure design palette and interaction space than the homoanionic oxide-only analogs. Here, established atomic and electronic principles for the rational design of properties in heteroanionic materials are contextualized. Also described are synergistic quantum mechanical methods and laboratory experiments guided by these principles to achieve superior properties. Lastly, open challenges in both the synthesis and the understanding and prediction of the electronic, optical, and magnetic properties afforded by anion-engineering principles in heteroanionic materials are reviewed.

Atomic Defects in Two-Dimensional Materials: From Single-Atom Spectroscopy to Functionalities in Opto-/Electronics, Nanomagnetism, and Catalysis

Two-dimensional layered graphene-like crystals including transition-metal dichalcogenides (TMDs) have received extensive research interest due to their diverse electronic, valleytronic, and chemical properties, with the corresponding optoelectronics and catalysis application being actively explored. However, the recent surge in two-dimensional materials science is accompanied by equally great challenges, such as defect engineering in large-scale sample synthesis. It is necessary to elucidate the effect of structural defects on the electronic properties in order to develop an application-specific strategy for defect engineering. Here, two aspects of the existing knowledge of native defects in two-dimensional crystals are reviewed. One is the point defects emerging in graphene and hexagonal boron nitride, as probed by atomically resolved electron microscopy, and their local electronic properties, as measured by single-atom electron energy-loss spectroscopy. The other will focus on the point defects in TMDs and their influence on the electronic structure, photoluminescence, and electric transport properties. This review of atomic defects in two-dimensional materials will offer a clear picture of the defect physics involved to demonstrate the local modulation of the electronic properties and possible benefits in potential applications in magnetism and catalysis.

High-throughput DFT calculations of formation energy, stability and oxygen vacancy formation energy of ABO3 perovskites

ABO3 perovskites are oxide materials that are used for a variety of applications such as solid oxide fuel cells, piezo-, ferro-electricity and water splitting. Due to their remarkable stability with respect to cation substitution, new compounds for such applications potentially await discovery. In this work, we present an exhaustive dataset of formation energies of 5,329 cubic and distorted perovskites that were calculated using first-principles density functional theory. In addition to formation energies, several additional properties such as oxidation states, band gap, oxygen vacancy formation energy, and thermodynamic stability with respect to all phases in the Open Quantum Materials Database are also made publicly available. This large dataset for this ubiquitous crystal structure type contains 395 perovskites that are predicted to be thermodynamically stable, of which many have not yet been experimentally reported, and therefore represent theoretical predictions. The dataset thus opens avenues for future use, including materials discovery in many research-active areas.

Structure and chemistry of graphene oxide in liquid water from first principles

Graphene oxide is a rising star among 2D materials, yet its interaction with liquid water remains a fundamentally open question: experimental characterization at the atomic scale is difficult, and modeling by classical approaches cannot properly describe chemical reactivity. Here, we bridge the gap between simple computational models and complex experimental systems, by realistic first-principles molecular simulations of graphene oxide (GO) in liquid water. We construct chemically accurate GO models and study their behavior in water, showing that oxygen-bearing functional groups (hydroxyl and epoxides) are preferentially clustered on the graphene oxide layer. We demonstrated the specific properties of GO in water, an unusual combination of both hydrophilicity and fast water dynamics. Finally, we evidence that GO is chemically active in water, acquiring an average negative charge of the order of 10 mC m-2. The ab initio modeling highlights the uniqueness of GO structures for applications as innovative membranes for desalination and water purification.

Identification of Fenton-like active Cu sites by heteroatom modulation of electronic density

The Fenton-like process based on peroxymonosulfate (PMS) has been widely investigated and recognized as a promising alternative in recent years for the degradation of persistent organic pollutants. However, the sluggish kinetics of PMS activation results in prohibitive costs and substantial chemical inputs, impeding its practical applications in water purification. This work demonstrates that tuning the electronic structure of single-atom sites at the atomic level is a powerful approach to achieve superior PMS activation kinetics. The Cu-based catalyst with the optimized electronic structure exhibits superior performance over most of the state-of-the-art heterogeneous Fenton-like catalysts, while homogeneous Cu(II) shows very poor activity. This work provides insights into the electronic structure regulation of metal centers and structure–activity relationship at the atomic level.

Developing heterogeneous catalysts with atomically dispersed active sites is vital to boost peroxymonosulfate (PMS) activation for Fenton-like activity, but how to controllably adjust the electronic configuration of metal centers to further improve the activation kinetics still remains a great challenge. Herein, we report a systematic investigation into heteroatom-doped engineering for tuning the electronic structure of Cu-N₄ sites by integrating electron-deficient boron (B) or electron-rich phosphorus (P) heteroatoms into carbon substrate for PMS activation. The electron-depleted Cu-N₄/C-B is found to exhibit the most active oxidation capacity among the prepared Cu-N₄ single-atom catalysts, which is at the top rankings of the Cu-based catalysts and is superior to most of the state-of-the-art heterogeneous Fenton-like catalysts. Conversely, the electron-enriched Cu-N₄/C-P induces a decrease in PMS activation. Both experimental results and theoretical simulations unravel that the long-range interaction with B atoms decreases the electronic density of Cu active sites and down-shifts the d-band center, and thereby optimizes the adsorption energy for PMS activation. This study provides an approach to finely control the electronic structure of Cu-N₄ sites at the atomic level and is expected to guide the design of smart Fenton-like catalysts.