Transition Metal Compounds Research Articles

High Stability Hypha-Like Core-Shell Nanostructure by In Situ Induced Phase Inversion for Zinc Metal Batteries.

Nanomaterials are widely used in many fields for their unique physical and chemical properties and especially demonstrate irreplaceability in energy storage systems. In this paper, a novel composite of copper sulfide with hypha-like core-shell nano-structure is synthesized by in situ phase inversion method, which serves as high stability negative electrode materials of zinc-ion batteries (ZIBs). The unique structure facilitates efficient electron and ion transport, enhances the kinetics of electrochemical reactions, and effectively suppresses the undesired expansion and decomposition of transition metal compounds. As a result, the half battery exhibits high specific capacity (250.2 mAh g-1 at 0.1 A g-1), reliable rate performance, and cycle stability (98.3 mAh g-1 at 1 A g-1 after 500 cycles). Additionally, when assembled with ZnxMnO2 positive to form a full battery, it demonstrates good cycling capacity at an intermediate current density of 2 A g-1, while maintaining excellent structural stability over 5,000 cycles (61% retention).

Nature of Excitons and Their Ligand-Mediated Delocalization in Nickel Dihalide Charge-Transfer Insulators

The fundamental optical excitations of correlated transition-metal compounds are typically identified with multielectronic transitions localized at the transition-metal site, such as dd transitions. In this vein, intense interest has surrounded the appearance of sharp, below-band-gap optical transitions, i.e., excitons, within the magnetic phase of correlated Ni2+ van der Waals magnets. The interplay of magnetic and charge-transfer insulating ground states in Ni2+ systems raises intriguing questions on the roles of long-range magnetic order and of metal-ligand charge transfer in the exciton nature, which inspired microscopic descriptions beyond typical dd excitations. Here we study the impact of charge transfer and magnetic order on the excitation spectrum of the nickel dihalides (NiX2, X=Cl, Br, and I) using Ni-L3 edge resonant inelastic x-ray scattering (RIXS). In all compounds, we detect sharp excitations, analogous to the recently reported excitons, and assign them to spin-singlet multiplets of octahedrally coordinated Ni2+ stabilized by intra-atomic Hund’s exchange. Additionally, we demonstrate that these excitons are dispersive using momentum-resolved RIXS. Our data evidence a ligand-mediated multiplet dispersion, which is tuned by the charge-transfer gap and independent of the presence of long-range magnetic order. This reveals the mechanisms governing nonlocal interactions of on-site dd excitations with the surrounding crystal or magnetic structure, in analogy to ground-state superexchange. These measurements thus establish the roles of magnetic order, self-doped ligand holes, and intersite-coupling mechanisms for the properties of dd excitations in charge-transfer insulators. Published by the American Physical Society 2024

Enhanced nitrogen electroreduction to ammonia activities on Sb2S3 electrocatalyst by sulfur defects coupled with carbon doping

Exploiting effective, robust while cheap catalysts for the nitrogen reduction reaction (NRR) is of great significance in the scalability and renewability of electrochemical NH3 synthesis. Herein, a synergetic strategy of C dopants and S vacancies was employed into Sb2S3 (marked as C-Sb2S3-x) to boost the electrochemical NRR performance. The induced effects of C dopants and S vacancies of Sb2S3 on the physical and electrochemical behaviors were throughly investigated. Experiments verify that, the content of low oxidation state in Sb species are remarkably enhanced after introducing C dopants and S vacancies, this facilitate the enhanced electric conductivity and NRR activities of C-Sb2S3-x, together with the encouraged reaction kinetics. The prepared C-Sb2S3-x delivered an optimized NH3 yield rate of 47.2 μg h−1 mg−1cat. at −0.6 V along with a high Faradaic efficiency value of 6.4 % at −0.5 V in acid, outperforming than those of Sb2S3 and most disclosed sulfid NRR electrocatalysts. Density functional theory calculations validate that, cooperation of C doping and S vacancy could achieve the elevated NH3 yield rate, Faradaic efficiency as well as competitive stability. This approach puts forward an effective strategy for transition metal compounds to be more suitable for efficient electrocatalysis.

Augmented Electrochemical Oxygen Evolution by d-p Orbital Electron Coupling.

While high-entropy alloys, high-entropy oxides, and high-entropy hydroxides, are advanced as a novel frontier in electrocatalytic oxygen evolution, their inherent activity deficiency poses a major challenge. To achieve the unlimited goal to tailor the structure-activity relationship in multicomponent systems, entropy-driven composition engineering presents substantial potential, by fabricating high-entropy anion-regulated transition metal compounds as sophisticated oxygen evolution reaction electrocatalysts. Herein, a versatile 2D high-entropy metal phosphorus trisulfide is developed as a promising and adjustable platform. Leveraging the multiple electron couplings and d-p orbital hybridizations induced by the cocktail effect, the exceptional oxygen evolution catalytic activity is disclosed upon van der Waals material (MnFeCoNiZn)PS3, exhibiting an impressively low overpotential of 240mV at a current density of 10mA cm-2, a minimal Tafel slope of 32mV dec-1, and negligible degradation under varying current densities for over 96 h. Density functional theory calculations further offer insights into the correlation between orbital hybridization and catalytic performance within high-entropy systems, underscoring the contribution of active phosphorus centers on the substrate to performance enhancements. Moreover, by achieving electron redistribution to optimize the electron coordination environment, this work presents an effective strategy for advanced catalysts in energy-related applications.

FeP nanoparticle embedded in N,P-doped 3D porous wood-derived carbon aerogel for oxygen reduction reaction

Metal-air batteries require the exploration of affordable electrocatalysts with exceptional catalytic performance for oxygen reduction reactions (ORR). One of the powerful ways to develop highly active and robust oxygen electrocatalysts is to load transition metal compounds onto a highly porous carbon aerogel. Here, we report a cell wall nanoengineering strategy to transform natural balsa wood into a wood-derived carbon aerogel (WCA), following by loading FeP nanoparticles inside the hierarchical N, P-doped WCA for ORR electrocatalysts. Wood nanotechnology is applied to manipulate the microstructure of the porous carbon aerogel with low-tortuosity, multichannel, and aligned pore, which benefits to the electron transportation for boosting the ORR. Under 0.1 M KOH conditions, the initial potential, half wave potential and limit current of FeP@N,P-WCA are 0.95 V, 0.84 V, and 5.20 mA cm−2 respectively, which are much higher than that of untreated wood and comparable to commercial Pt/C. The aqueous Zn-air batteries assembled with this catalyst exhibit a remarkable specific capacity of 775.5 mA h g−1 and better charge-discharge cycling stability. The excellent electrocatalytic activity demonstrated by FeP@N,P-WCA for ORR is attributed to the inherent tri-pathway (lumen, pit, and ray cell) porous structure of wood, the high conductivity and specific surface area of WCA (584.2 m2 g−1), and the highly dispersed FeP nanoparticles. This work provides a structural design concept for achieving high electrocatalytic biobased WCA reactors by combining wood nanotechnology and electrocatalysts chemistry for energy storage and conversion.

Using Iron L-Edge and Nitrogen K-Edge X-ray Absorption Spectroscopy to Improve the Understanding of the Electronic Structure of Iron Carbene Complexes.

Iron-centered N-heterocyclic carbene compounds have attracted much attention in recent years due to their long-lived excited states with charge transfer (CT) character. Understanding the orbital interactions between the metal and ligand orbitals is of great importance for the rational tuning of the transition metal compound properties, e.g., for future photovoltaic and photocatalytic applications. Here, we investigate a series of iron-centered N-heterocyclic carbene complexes with +2, + 3, and +4 oxidation states of the central iron ion using iron L-edge and nitrogen K-edge X-ray absorption spectroscopy (XAS). The experimental Fe L-edge XAS data were simulated and interpreted through restricted-active space (RAS) and multiplet calculations. The experimental N K-edge XAS is simulated and compared with time-dependent density functional theory (TDDFT) calculations. Through the combination of the complementary Fe L-edge and N K-edge XAS, direct probing of the complex interplay of the metal and ligand character orbitals was possible. The σ-donating and π-accepting capabilities of different ligands are compared, evaluated, and discussed. The results show how X-ray spectroscopy, together with advanced modeling, can be a powerful tool for understanding the complex interplay of metal and ligand.

The Synthesis and Crystallographic Characterization of Emissive Pt(II) and Au(I) Compounds Exploiting the 2-Ethynylpyrimidine Ligand

The luminescent properties of Au(I) and Pt(II) compounds are commonly tuned by exploiting the alkynyl ligand with varying electron density. Herein, we describe the synthesis of three new emissive transition metal compounds, tbpyPt(C2pym)2, Ph3PAuC2pym, and Cy3PAuC2pym (where HC2pym = 2-ethynylpyrimidine), verified by 1H-NMR, EA, and a single-crystal X-ray diffraction analysis. The tbpyPt(C2pym)2 complex crystallized as an Et2O solvate in the orthorhombic space group Pbca with Z = 24 with three unique Pt(II) species within the unit cell. The Cy3PAuC2pym species crystallizes in a monoclinic space group with one unique complex in the asymmetric unit. Changing the identity of the phosphine from Cy3P to Ph3P influences interactions within the unit cell. Ph3PAuC2pym, which also crystalizes in a monoclinic space group, has an aurophilic bonding interaction Au–Au distance of 3.0722(2) Å, which is not present in crystalline Cy3PAuC2pym. Regarding optical properties, the use of an electron-deficient heterocycle provides an alternate approach to blue-shifting the emission of Pt(II) transition metals’ compounds, where the aryl moiety is made more electron-deficient by exploiting nitrogen within this moiety instead of the typical strategy of decorating the aryl ring with electron withdrawing substituents (e.g., fluorines). This is indicated by the blue-shift in emission that occurs in tbpyPt(C2pym)2 (λmax, emission = 512 nm) compared to the previously reported tbpyPt(C22-py)2 (where HC22-py = 2-ethynylpyridine) complex (λmax, emission = 520 nm).

Nitrogen-metal-oxygen moieties enriched surface reconstruction in CoFe electrocatalysts for stabilizing high-valence Co sites enable water oxidation

Despite the potential of heterostructure construction and surface reconstruction strategies to significantly enhance the oxygen evolution reaction (OER) performance of transition metal compounds, integrating these approaches into a single material system remains a significant challenge. In this work, we report an efficient CoFe-LDH catalyst with multi-metal nitrides on the surface through simple and tunable N2-plasma treatment (PL CoFe-LDH). Structural characterization and theoretical calculations indicate a high concentration of defective sites in PL CoFe-LDH, which facilitates the exposure of a greater number of active NFeO and NCoO centers. During the initial stage of the OER process, there is a rapid phase transition of Fe and Co, leading to the formation of metal (oxy)hydroxides. Meanwhile, Co3+ species gradually accumulate on the surfaces, which is responsible for the excellent OER catalytic activity. Then, the neighboring N atoms function as electron reservoirs, donating electrons to the Co sites to prevent overoxidation and dissolution of Co in the electrolyte, thus significantly enhancing the stability of the OER. The catalysts enable the achievement of ultralow OER overpotential, measuring 161.1 and 205.5 mV at current densities of 10 mA cm−2 and 200 mA cm−2, respectively, while exhibiting exceptional stability.

Four polyoxomolybdated-based 3D compounds as supercapacitors and amperometric sensors.

Fourpolyoxomolybdated compounds based on Tetp (Tetp = 4-[4-(2-Thiophen-2-yl-ethyl)-4H-[1, 2, 4]triazole-3-yl]-pyridine), namely [Zn(Tetp)2(H2O)2][(β-Mo8O26)0.5] (Zn-Mo8), [Co(Tetp)2(H2O)2][(β-Mo8O26)0.5] (Co-Mo8), [Cu4(Tetp)6(H2O)2]{H3[K(H2O)3](θ-Mo8O26)(Mo12O40)}·8H2O (Cu-Mo20) and [Cu3(Tetp)3][PMo12O40]·H2O (Cu-PMo12) are synthesized by hydrothermal methods and are used as electrode materials for supercapacitors(SCs) and electrochemical sensors. Inserting polyoxometalates (POMs) with redox active sites into transition metal compounds (TMCs) can improve the internal ion/electron transfer rate, thus effectively enhancing the electrochemical performance. Compared with the parent POMs, four compounds exhibit excellent electrochemical properties. In particular, Cu-PMo12 shows an excellent specific capacitance (812.3F g-1 at 1A g-1) and stability (94.42%), as well as a wide detection range (0.05 to 1250 µM) and a low detection limit (0.057 µM) for NO2- sensing.

Highly efficient electrocatalytic water oxidation based on non-precious metal oxides/sulfides derived from a FeCoNi-metal organic framework

One of the main challenges for oxygen evolution reaction (OER) is to develop electrocatalysts with high performance, suitable stability, and low cost. First-row transition metal compounds have received attention due to their high electrocatalytic activity and diverse electronic structure. Meanwhile, metal-organic frameworks (MOFs) have emerged as promising alternative for OER due to their porous structure and unsaturated metal sites. In this study, FeCoNi-MOF based on MIL-88B was synthesized by a hydrothermal method. Then, the performance of the catalyst was investigated and improved by calcination and sulfidation at three temperatures of 250 ℃, 350 ℃, and 450 ℃. The phase development and crystal structure parameters of the synthesized samples were confirmed through X-ray diffraction. Additionally, the intensity of the peaks increased with the rise in calcination temperature. Field emission scanning electron microscopy revealed well-defined and uniformly distributed nanorods and nanospheres particles of calcinated and sulfides samples. The weight percentage (wt%) of the elements in the samples were verified to align with their stoichiometric ratios. The synthesized catalysts were loaded onto a nickel foam by a one-step method, and their electrocatalytic properties were examined in the OER process in 1.0 M KOH alkaline solution. The (FeCoNi)-O250 ℃ electrocatalyst, maintaining its nanorod morphology, exhibited an overpotential of 313 mV at a current density of 10 mA.cm-² and a small, stable Tafel slope of 31.5 mV.dec−1 and good charge transfer of 0.73 mF. Cm−2. However, the (FeCoNi)-S250 ℃ electrocatalyst showed better performance in the OER process with an overpotential of 298 mV at a current density of 10 mA.cm-² and a small and stable Tafel slope of 29 mV.dec−1 and good charge transfer of 0.82 mF. Cm−2. In other words, a higher Cdl increased reaction rates or lower overpotentials required for the reaction to occur. Furthermore, the activity of this catalyst remained constant at a fixed current density of 10 mA.cm-² for 18 hours. Based on the electron microscopy observations, and electrochemical evaluations, this superior performance can be attributed to the morphological change from nanorods to porous nanospheres due to sulfidation, resulting in increased electrochemically active sites and decreased charge transfer resistance.

Three-dimensional hidden phase probed by in-plane magnetotransport in kagome metal CsV3Sb5 thin flakes

Transition metal compounds with kagome structure have been found to exhibit a variety of exotic structural, electronic, and magnetic orders. These orders are competing with energies very close to each other, resulting in complex phase transitions. Some of the phases are easily observable, such as the charge density wave (CDW) and the superconducting phase, while others are more challenging to identify and characterize. Here we present magneto-transport evidence of a new phase below ~ 35 K in the kagome topological metal CsV3Sb5 (CVS) thin flakes between the CDW and the superconducting transition temperatures. This phase is characterized by six-fold rotational symmetry in the in-plane magnetoresistance (MR) and is connected to the orbital current order in CVS. Furthermore, the phase is characterized by a large in-plane negative magnetoresistance, which suggests the existence of a three-dimensional, magnetic field-tunable orbital current ordered phase. Our results highlight the potential of magneto-transport to reveal the interactions between exotic quantum states of matter and to uncover the symmetry of such hidden phases.

Enhancing oxygen evolution reaction through self-reconstruction of 2D nanoarrays on nickel foam

The synthesis of nanostructured transition metal compounds with adjustable components are often challenging due to the involvement of multiple synthetic procedures or complex manipulations. In this work, a one-step self-regulating acid-etching strategy is employed for nickel iron-layered double hydroxide (NiFe LDH). A two-dimensional (2D) NiFe LDH nanosheet is speedy and efficiently formed. This as-prepared NiFe LDH exhibits electrocatalytic activity for oxygen evolution reaction (OER). This approach avoids numerous structural design challenges and provides highly active sites and a robust interface between catalyst and support. As a result, 2D NiFe LDH electrodes demonstrate highly efficient OER performance with a low overpotential of 300 mV and a Tafel slope of 70.6 mV dec−1 at a current density of 100 mA cm−2.

Conjugated polyaniline as “conveyor” in tungstate boosting cation storage for high-performance aqueous batteries

Aqueous ion storage systems have motivated great interest by virtue of low reduction, high eco-sustainability and safety. Among various cathode candidates, transition metal compounds are featured with easy dissolution in aqueous solutions and inferior conductivity, which severely hinder their application. Herein, advantages are taken of the “conveyor effect” of conjugated polyaniline to prepare an oxygen defective tungstate-linked polyaniline (Od-WOP) material with chrysanthemum-like microstructure. By virtue of the high electronic conductivity derived from conductive conjugated polyaniline skeleton, unbalanced charge distribution triggered by the defective structure, and reversibly rapid ion (de)intercalation benefited from the open framework with porous chrysanthemum-like microstructure, it delivers outstanding rate capability with a maximum specific capacity of 162.2 mAh g−1 and great cycle stability for storing NH4+. Additionally, it also adopts a high reversible capacity of 140.4 mAh g−1 and outstanding cycling performance to store Ca2+. Consequently, the assembled Od-WOP//PTCDI flexible aqueous ammonium ion batteries and calcium ion batteries exhibit superior capacities, energy densities and flexibilities. Od-WOP achieves the NH4+ and Ca2+ storage capability by interacting with them through hydrogen and ionic bonds, respectively. The deep insight from this work sheds light upon a novel strategy to excavate greater potential of transition metal compounds for aqueous ion batteries.

Innovative amorphous multiple anionic transition metal compound electrode for extreme environments (≤ −80 °C) battery operations

The demand for lithium-ion batteries (LIBs) that function reliably in extreme environments has driven research efforts towards optimizing electrolyte composition, solid electrolyte interphase formation, and electrode materials. In this study, we pioneer an approach that utilizes amorphous-structured multiple anionic transition metal compounds as anodes, strategically paired with a cyclopentyl methyl ether (CPME)-based electrolyte, known for facilitating efficient Li+ conduction at low-temperatures. The synergistic effect yields exceptional LIB performance over a wide range of operating temperatures, stemming from the unique iron hydroxyl selenide (Fe(OH)Se) anode with a layered structure, enhanced ion diffusion pathways, and reduced energy requirements for conversion reactions combined with the CPME-based electrolyte. Specifically, Li//Fe(OH)Se LIBs with the CPME-based electrolyte exhibits initial discharge capacities of 974.7 mA h g−1 (at 1.0 A g−1) at room temperature, 285.2 mA h g−1 (at 0.025 A g−1) at −80 °C, and 1066.9 mA h g−1 (at 0.2 A g−1) at 45 °C. Notably, even at the extreme low-temperature of −100 °C, these LIBs remain operable.

Synthesis and thermal insulation properties of (Ti1/5V1/5Mo1/5Nb1/5Ta1/5)(C0.55N0.45) high-entropy carbonitride porous ceramic

Porous high-entropy transition metal compounds, an important type of ultra-high temperature material, have attracted increasing attention in the applications of extreme environments due to their low density, good thermal insulation and stable chemical properties. A robust, flame-retardant and high-temperature resistant high-entropy carbonitride (Ti1/5V1/5Mo1/5Nb1/5Ta1/5)(C0.55N0.45) (HECN) porous ceramic was synthesized and thoroughly characterized. It exhibited a porosity of 93.5 %, a compressive strength of 1.3 MPa and a good high-temperature stability up to 1673 K, which, along with its outstanding fire-retardancy, and low thermal conductivity (as low as 0.150 W m−1 K−1 at 298 K), made it a good candidate material for thermal insulation applications in ultra-high temperature environments. Moreover, the Density functional theory (DFT) calculations predict that the [N]/([C]+[N]) ratio in HECN foam affects its lattice thermal conductivity which is decreased by 67 % upon increasing the ratio from 0 to 1/2.

Mechanism research progress on transition metal compound electrode materials for supercapacitors

Mechanism research progress on transition metal compound electrode materials for supercapacitors

Predictive Synthesis of Transition Metal Carbide via Thermochemical Oxocarbon Equilibrium.

Fabricating nanoscale metal carbides is a great challenge due to them having higher Gibbs free energy of formation (ΔG°) values than other metal compounds; additionally, these carbides have harsh calcination conditions, in which metal oxidation is preferred in the atmosphere. Herein, we report oxocarbon-mediated calcination for the predictive synthesis of nanoscale metal carbides. The thermochemical oxocarbon equilibrium of CO-CO2 reactions was utilized to control the selective redox reactions in multiatomic systems of Mo-C-O, contributing to the phase-forming and structuring of Mo compounds. By harnessing the thermodynamically predicted processing window, we controlled a wide range of Mo phases (MoO2, α-MoC1-x, and β-Mo2C) and nanostructures (nanoparticle, spike, stain, and core/shell) in the Mo compounds/C nanofibers. By inducing simultaneous reactions of C-O (selective C combustion) and Mo-C (Mo carbide formation) in the nanofibers, Mo diffusion was controlled in C nanofibers, acting as a template for the nucleation and growth of Mo carbides and resulting in precise control of the phases and structures of Mo compounds. The formation mechanism of nanostructured Mo carbides was elucidated according to the CO fractions of CO-CO2 calcination. Moreover, tungsten (W) and niobium (Nb) carbides/C nanofibers have been successfully synthesized by CO-CO2 calcination. We constructed the thermodynamic map for the predictive synthesis of transition metal carbides to provide universal guideline via thermochemical oxocarbon equilibrium. We revealed that our thermochemical oxocarbon-mediated gas-solid reaction enabled the structure and phase control of nanoscale transition metal compounds to optimize the material-property relationship accordingly.

Topological magnons in a non-coplanar magnetic order on the triangular lattice

The bond-dependent Kitaev interaction K is familiar in the effective spin model of transition metal compounds with octahedral ligands. In this work, we find a peculiar non-coplanar magnetic order can be formed with the help of K and next-nearest neighbor Heisenberg coupling J 2 on the triangular lattice. It can be seen as a miniature version of skyrmion crystal, since it has nine spins and an integer topological number in a magnetic unit cell. The magnon excitations in such an order are studied by the linear spin-wave theory. Of note is that the change in the relative size of J 2 and K produces topological magnon phase transitions although the topological number remains unchanged. We also calculated the experimentally observable thermal Hall conductivity, and found that the signs of thermal Hall conductivity will change with topological phase transitions or temperature changes in certain regions.

Universal, minute-scale synthesis of transition metal compound nanocatalysts via graphene-microwave system for enhancing sulfur kinetics in lithium-sulfur batteries

The application of Li-S batteries on large scale is held back by the sluggish sulfur kinetics and low synthesis efficiency of sulfur host. In addition, the preparation of catalysts that promote polysulfide redox kinetics is complex and time-consuming, reducing the cost of raw materials in Li-S. Here, a universal synthetic strategy for rapid fabrication of sulfur cathode and metal compounds nanocatalysts is reported based on microwave heating of graphene. Heat-sensitive materials can achieve rapid heating due to graphene reaching 500 ℃ within 4 s via microwave irradiation. The MoP-MoS2/rGO catalyst demonstrated in this work was synthesized within 60 s. When used for catalysts for Li-S batteries whose graphene/sulfur cathodes were also synthesized by microwave heating, enhanced catalytic effect for sulfur redox reaction was verified via experimental and DFT theoretical results. Benefiting from fast redox reaction (MoP), smooth Li+ diffusion pathways (MoS2), and large conductive network (rGO), the assembled Li-S battery with MoP-MoS2/rGO-Add@CS displays a remarkable initial specific capacity, stable lithium anode and good cycle stability (in pouch cells) using this two-pronged strategy. The work provides a practical strategy for advanced Li-S batteries toward a wide range of applications.

The Surface Confinement of FeO Assists in the Generation of Singlet Oxygen and High-Valent Metal-Oxo Species for Enhanced Fenton-Like Catalysis.

Transition metal compounds (TMCs) have long been potential candidate catalysts in persulfate-based advanced oxidation process (PS-AOPs) due to their Fenton-like catalyze ability for radical generation. However, the mechanism involved in TMCs-catalyzed nonradical PS-AOPs remains obscure. Herein, the growth of FeO on the Fe3O4/carbon precursor is regulated by restricted pyrolysis of MIL-88A template to activate peroxymonosulfate (PMS) for tetracycline (TC) removal. The higher FeO incorporation conferred a 2.6 times higher degradation performance than that catalyzed by Fe3O4 and also a higher interference resistance to anions or natural organic matter. Unexpectedly, the quenching experiment, probe method, and electron paramagnetic resonance quantitatively revealed that the FeO reassigned high nonradical species (1O2 and FeIV═O) generation to replace original radical system created by Fe3O4. Density functional theory calculation interpreted that PMS molecular on strongly-adsorbed (200) and (220) facets of FeO enjoyed unique polarized electronic reception for surface confinement effect, thus the retained peroxide bond energetically supported the production of 1O2 and FeIV═O. This work promotes the mechanism understanding of TMCs-induced surface-catalyzed persulfate activation and enables them better perform catalytic properties in wastewater treatment.