Fe Sites Research Articles

Engineering d-p Orbital Hybridization in Mo-O Species of Medium-Entropy Metal Oxides as Highly Active and Stable Electrocatalysts toward Ampere-Level Water/Seawater Splitting.

Optimizing the electronic structure of electrocatalysts is of particular importance to enhance the intrinsic activity of active sites in water/seawater. Herein, a series of medium-entropy metal oxides of X(NiMo)O2/NF (X = Mn, Fe, Co, Cu and Zn) is designed via a rapid carbothermal shocking method. Among them, the optimized medium-entropy metal oxide (FeNiMo)O2/NF delivered remarkable HER performance, where the overpotentials as low as 110 and 141mV are realized at 1000 mAcm-2 (@60°C) in water and seawater. Meanwhile, medium-entropy metal oxide (FeNiMo)O2/NF only required overpotentials of as low as 330 and 380mV to drive 1000mAcm-2 for OER in water and seawater (@60°C). Theoretical calculations showed that the multiple-metal synergistic effect in medium-entropy metal oxides can effectively enhance the d-p orbital hybridization of Mo─O bond, reduce the energy barrier of H* adsorbed at the Mo sites. Meanwhile, Fe sites in medium-entropy metal oxide can act as the real OER active center, resulting in a good bifunctional activity. In all, this work provides a feasible strategy for the development of highly active and stable medium-entropy metal oxide electrocatalysts for ampere-level water/seawater splitting.

Single-Atom Fe-Catalyzed Acceptorless Dehydrogenative Coupling to Quinolines.

A single-atom iron catalyst was found to exhibit exceptional reactivity in acceptorless dehydrogenative coupling for quinoline synthesis, outperforming known homogeneous and nanocatalyst systems. Detailed characterizations, including aberration-corrected HAADF-STEM, XANES, and EXAFS, jointly confirmed the presence of atomically dispersed iron centers. Various functionalized quinolines were efficiently synthesized from different amino alcohols and a range of ketones or alcohols. The iron single-atom catalyst achieved a turnover number (TON) of up to 105, far exceeding the results of current homogeneous and nanocatalyst systems. Detailed mechanistic studies verified the significance of single-atom Fe sites in the dehydrogenation process.

Superoxide radicals mediated by high-spin Fe catalysis for organic wastewater treatment

Water resources are indispensable basic resources and important environmental carriers; the presence of organic contaminants in wastewater poses considerable risks to the health of both humans and ecosystems. Although the Fenton-like reactions using H2O2 as the oxidant to destroy organic pollutants are attractive, there are still challenges in improving reaction activity under neutral or even alkaline conditions. Herein, we designed a H2O2 activation pathway with O2•- as the main active species and elucidated that the spin interaction between Fe sites and coordinated O atoms effectively promotes the generation of the key intermediate Fe-*OOH. Furthermore, we successfully captured and analyzed the Fe-*OOH intermediate by in situ Raman spectroscopy. When applying FBOB to a continuous-flow reactor, CIP removal efficiency remained at around 90% within 600 min of continuous operation, achieving excellent efficiency, stability, and pH tolerance in removing pollutants.

Superconductivity of Co-Doped CaKFe4As4 Investigated via Point-Contact Spectroscopy and London Penetration Depth Measurements.

The iron-based superconductors (IBSs) of the recently discovered 1144 class, unlike many other IBSs, display superconductivity in their stoichiometric form and are intrinsically hole doped. The effects of chemical substitutions with electron donors are thus particularly interesting to investigate. Here, we study the effect of Co substitution in the Fe site of CaKFe4As4 single crystals on the critical temperature, on the energy gaps, and on the superfluid density by using transport, point-contact Andreev-reflection spectroscopy (PCARS), and London penetration depth measurements. The pristine compound (Tc≃36 K) shows two isotropic gaps whose amplitudes (Δ1 = 1.4-3.9 meV and Δ2 = 5.2-8.5 meV) are perfectly compatible with those reported in the literature. Upon Co doping (up to ≈7% Co), Tc decreases down to ≃20 K, the spin-vortex-crystal order appears, and the low-temperature superfluid density is gradually suppressed. PCARS and London penetration depth measurements perfectly agree in demonstrating that the nodeless multigap structure is robust upon Co doping, while the gap amplitudes decrease as a function of Tc in a linear way with almost constant values of the gap ratios 2Δi/kBTc.

Structure and dielectric spectroscopy of double perovskite La2-xPrxCoFe1-yMnyO6 system

Double perovskites have shown promise in the development of spin polarized conduction and ferromag semiconductors. In this category of double perovskite, we report on the lanthanum ferrocobaltite, co-doped with Pr and Mn. The polycrystalline ceramics were analysed for its structural properties by using Rietveld refinement of X-ray diffraction (XRD) and Raman spectroscopy measurements. The pristine and co-doped samples possess monoclinic structure with P21/n space group. In the pristine compound Co and Fe octahedra are ordered periodically which later gets distorted upon cationic substitution. Scanning electron microscopy (SEM) and energy dispersive spectra (EDS) reveals the grain morphology and elemental analysis. The samples were investigated for their dc and ac electrical responses. The two-probe dc resistance was measured from room temperature RT to 575 K. Dielectric spectroscopy in the RT to 650 K temperature range was performed in the frequency range of 50 kHz to 5 MHz. We observed that introducing Pr at La-site and Mn at Fe site creates structural disorder and tilt in octahedra which results in decreasing the dielectric constant at RT but increases significantly at higher temperature with low dielectric loss. ac conductivity was found to increase with increasing temperature indicating the thermally governed hopping mechanism. All these features validate their potential applications as a high temperature capacitor and can be widely used in automotive and aerospace domains for the storage device application.

Sulfidation−reoxidation enhances heavy metal immobilization by vivianite

Iron minerals in nature are pivotal hosts for heavy metals, significantly influencing their geochemical cycling and eventual fate. It is generally accepted that, vivianite, a prevalent iron phosphate mineral in aquatic and terrestrial environments, exhibits a limited capacity for adsorbing cationic heavy metals. However, our study unveils a remarkable phenomenon that the synergistic interaction between sulfide (S2−) and vivianite triggers an unexpected sulfidation−reoxidation process, enhancing the immobilization of heavy metals such as cadmium (Cd), copper (Cu), and zinc (Zn). For instance, the combination of vivianite and S2− boosted the removal of Cd2+ from the aqueous phase under anaerobic conditions, and ensured the retention of Cd stabilized in the solid phase when shifted to aerobic conditions. It is intriguing to note that no discrete FeS formation was detected in the sulfidation phase, and the primary crystal structure of vivianite largely retained its integrity throughout the whole process. Detailed molecular-level investigations indicate that sulfidation predominantly targets the Fe(II) sites at the corners of the PO4 tetrahedron in vivianite. With the transition to aerobic conditions, the exothermic oxidation of CdS and the S sites in vivianite initiates, rendering it thermodynamically favorable for Cd to form multidentate coordination structures, predominantly through the Cd-O-P and Cd-O-Fe bonds. This mechanism elucidates how Cd is incorporated into the vivianite structure, highlighting a novel pathway for heavy metal immobilization via the sulfidation−reoxidation dynamics in iron phosphate minerals.

Constructing interfacial polarization to improve electrocatalytic nitrogen reduction reactions in polyoxometalates-based metal-organic framework-derived Fe7S8-WS2-Co9S8 multi-phase heterostructures

Electrocatalytic nitrogen (N2) reduction to produce ammonia (NH3) has received increasing attention. It is urgent to design highly active and environmentally friendly catalysts due to present electrocatalysts still suffering from poor stability and low catalytic efficacy. In this work, Fe7S8-WS2-Co9S8 multi-phase heterostructures are prepared by using a template-directed assembly approach. The uniform distribution of Fe7S8-WS2-Co9S8 nanosheets derived from polyoxometalate-based metal-organic frameworks (POMOFs) largely provides more reactive active sites and improves the enrichment efficiency of N2. Multi-phase heterojunction interface between Fe7S8, WS2 and Co9S8 enhances the interfacial polarisation and leads to electron transfer from WS2 to Fe7S8 and Co9S8, and further facilitated the reduction of N2 in the electron-rich Fe7S8, resulting in an ultrahigh NH3 yield of 51.21 μg·h·mgcat.−1 and a Faradaic efficiency of 34.12 %. Density Functional Theory (DFT) calculations indicate that Fe sites are favorable sites for N2 adsorption in Fe7S8-WS2-Co9S8 composites, and Fe7S8-WS2-Co9S8 is most likely to catalyze nitrogen reduction via the distal pathway. The current investigation provides a perspective for developing multi-phase heterogeneous catalysts for electrocatalytic NH3 from N2.

Trapping an Elusive Fe(IV)-Superoxo Intermediate Inside a Self-Assembled Nanocage in Water at Room Temperature.

Molecular cavities that mimic natural metalloenzymes have shown the potential to trap elusive reaction intermediates. Here, we demonstrate the formation of a rare yet stable Fe(IV)-superoxo intermediate at room temperature subsequent to dioxygen binding at the Fe(III) site of a (Et4N)2[FeIII(Cl)(bTAML)] complex confined inside the hydrophobic interior of a water-soluble Pd6L412+ nanocage. Using a combination of electron paramagnetic resonance, Mössbauer, Raman/IR vibrational, X-ray absorption, and emission spectroscopies, we demonstrate that the cage-encapsulated complex has a Fe(IV) oxidation state characterized by a stable S = 1/2 spin state and a short Fe-O bond distance of ∼1.70 Å. We find that the O2 reaction in confinement is reversible, while the formed Fe(IV)-superoxo complex readily reacts when presented with substrates having weak C-H bonds, highlighting the lability of the O-O bond. We envision that such optimally trapped high-valent superoxos can show new classes of reactivities catalyzing both oxygen atom transfer and C-H bond activation reactions.

Manipulating Superexchange Interaction of Ru–O–Fe Sites for Enhanced Electrocatalytic Nitrate-to-Ammonia Selectivity

Manipulating Superexchange Interaction of Ru–O–Fe Sites for Enhanced Electrocatalytic Nitrate-to-Ammonia Selectivity

Activation of Peroxodisulfate Coupled with Photocatalysis by Pyrrolic N‐Rich Fe‐N4 Sites for High Efficiency Degradation of Tetracycline Hydrochloride

AbstractPhotocatalysis is an efficient technology for the degradation of pollutants. However, there is still much room for improvement in its degradation efficiency. In this study, a pyrrolic N‐rich g‐C3N4 (PN‐g‐C3N4) framework was synthesized with transition metal M (M=Fe, Co, Ni, Cu, Cr, and Mn) atomic sites coordinated onto it. Then, a series of single atomic metals M anchored to PN‐g‐C3N4 (M/PN‐g‐C3N4) are constructed for peroxodisulfate activation. Their order of catalytic activity follows Fe>Cr>Ni>Cu≈Co>Mn, in particular the degradation rates of the TCH for Fe‐PN‐g‐C3N4 are 3.74 times higher than that of undoped PN‐g‐C3N4. These carefully regulated pyrrolic N‐rich Fe sites demonstrate outstanding performance in degrading organic pollutant. As an exemplary model, the Fe/PN‐g‐C3N4 catalyst efficiently drives the catalytic oxidation of TCH through Fenton‐like reaction under visible light, showcasing exceptional cycle stability and a broad effective pH range of 3.0–11.0. The synergy between photocatalysis and Fe doped catalysis results in increased generation and separation of charge carriers, along with the cyclic transformation of the Fe3+/Fe2+ couple. This combination significantly enhances the Fenton‐like performance, making it a highly effective process for pollutant degradation.

Engineering Synergetic Fe‐Co Atomic Pairs Anchored on Porous Carbon for Enhanced Oxygen Reduction Reaction

AbstractThe rational design of heteronuclear dual‐atom catalyst (DAC) is intricate due to the random dispersion of metal atoms under thermal treatment. Herein, a novel precursor pre‐orientation strategy is reported to construct Fe‐Co diatomic sites atomically dispersed on nitrogen doped carbon (Fe‐Co‐NC) via cubic Prussian blue analogue as metal source. Due to the specific synergy between Fe and Co centers, the obtained Fe‐Co‐NC catalyst renders outstanding oxygen reduction reaction (ORR) performance with positive half‐wave potential and good durability in wide pH range. Density functional theory further clarifies the active centers and reveals that the Fe‐Co‐NC dual atomic catalyst follows the modulation mechanism, where the intermediates tended to adsorb on Fe site, while the neighboring Co atom can assist by lowering the d‐band center of Fe site. Experimentally and theoretically emphasizes the priority of heteronuclear diatomic Fe‐Co catalysts over homonuclear Fe‐Fe‐NC and Co‐Co‐NC DAC. Moreover, the Zn‐Air battery (ZAB) and microbial fuel cell (MFC) assembled with Fe‐Co‐NC cathodes both exhibit splendid power density (382 mW cm−2 for ZAB, 2034 ± 103 mW m−2 for MFC) as well as excellent stability. This work provides a new perspective for rational construction and precise regulation for heteronuclear dual‐atom catalysts.

Iron-cobalt phosphide/nitrogen-doped carbon composite derived from prussian blue analogues as anode materials for sodium-ion batteries

Transition metal phosphides (TMPs) are recognized as attractive substitutes for lithium/sodium storage owing to their notable capacity and outstanding safety features. However, they face significant challenges in applications, particularly poor cycling stability and rapid capacity decay. In this study, we report a simple strategy utilizing dopamine-coated Prussian blue analogues as precursors to prepare bimetallic iron‑cobalt phosphide/nitrogen-doped carbon (Fe1-xCoxP/NC) composite materials via a one-step carbothermal phosphorization process. Benefiting from their nanostructured advantages and electronic interactions between Fe and Co sites, Fe0.17Co0.83P/NC, prepared by adjusting and optimizing the ion ratio, exhibits excellent rate capability and cycling performance as an anode material for sodium-ion batteries. It achieves a high specific capacity of 505.6 mAh g−1 at 0.5 A g−1. Even after 1000 cycles at a high current of 1 A g−1, the reversible specific capacity remains at 413.6 mAh g−1. Ex-situ XRD studies confirm that Fe0.17Co0.83P/NC stores Na+ via a conversion mechanism, where the crystalline CoP phase transforms into Na3P phase during the discharging process.

One Iron for Two Iron Sites in a Metal-Organic Framework Toward Simultaneous N2-H2 Activation under Mild Conditions.

Iron-based catalysts play an important role in the ammonia industry. As one of the most abundant iron minerals, Fe3O4 containing FeII and FeIII sites is widely distributed in the earth's crust and even on exoplanets, theoretically giving it both economic and catalytic potentials in ammonia synthesis. However, in the absence of specific active co-catalyst and harsh conditions, Fe3O4 is impossible to achieve ammonia synthesis alone. Here, we designed to activate the relatively inert FeII and FeIII sites in Fe3O4 with a third FeIII site inlayed in a coordination framework (MIL-101(Fe)) to achieve the unpresented multi-site collaborative catalysis. In-depth mechanism study confirmed the roles of three different Fe sites in N2 activation, H2 activation, and product transfer, respectively. Efficient N2-H2 activation to NH3 on the Fe3O4-based catalytic system has been achieved at extremely mild conditions. Our research provides a theoretical basis and a new strategy for designing efficient non-noble metal-based ammonia synthesis catalyst with minimized energy consumption.

Effective and green in-situ remediation strategies based on TEMPO-nanocellulose/lignin/MIL-100(Fe) hydrogel nanocomposite adsorbent for lead and copper in agricultural soils

Hydrogel adsorbents are promising tools for reducing heavy metals' bioavailability in contaminated soil. However, their practical feasibility remains limited by the low stability, inefficient removal efficiency, and potential secondary pollution. Optimizing the adsorption operation and the functional properties of hydrogel adsorbents could eliminate this method's drawbacks. Herein, three innovative in-situ remediation strategies for Pb/Cu-contaminated soil were adopted based on the concept of novel TEMPO-cellulose (TO-NFCs)/lignin/acrylamide@MIL-100(Fe) nanocomposite hydrogel adsorbent (NCLMH). Characteristic analyses revealed ideal Pb/Cu adsorption mechanisms by swelling, complexation, electrical attraction, and ion exchange via carboxyl/hydroxyl/carbonyl groups and unsaturated Fe(III) sites on ANCMH besides FeOOH formation. The highest maximum theoretical adsorption capacities of Pb(II) and Cu(II) on ANCMH were 416.39 and 133.98 mg/g, under pH 6.5, governed by pseudo-second-order/Freundlich models. Greenhouse pot experiments with contaminated soils amended with two-depth layers of 0.5% NCLMHs (SA@NCLMH) displayed a decline in Pb and Cu bioavailability up to 85.9% and 74.5% within 45 d. Soil column studies simulating continuous water soil flushing coupled with NCLMH layers, instead of conventional extractant fluids, and connected to NCLMH-sand column as purification unit (CF@NCLMH) achieved higher removal rates for Pb, and Cu of 89.5% and 77.2% within 24 h. Alternatively, conducting multiple-pulse soil flushing mode (MF@NCLMH) gained the highest Pb and Cu removal of 96.5% and 85.4%, as the water flushing-stop flux events allowed adequate water movement/residence period, promoting Pb/Cu desorption-adsorption from soil to NCLMH. Also, the NCLMH-sand column conducting and easy separation of the stable/reusable NCLMHs prevented the potential secondary pollution. Interestingly, the three remediated soils reached the corresponding regulation of the permissible limits for Pb and Cu residential scenarios in medium-to-heavily agricultural polluted soils, alleviating the Pb/Cu bioaccumulation and phytotoxicity symptoms in cultivated wheat, especially after MF@NCLMH treatment. This study introduces promising alternative remediation strategies with high sustainability and feasibility in acidic-to-neutral heavy metal-contaminated agricultural soil.

Unveiling the overlooked role of structural heterogeneity within Fe-N-C single atom catalysts for Fenton-like reactions: Efficient decontamination of pharmaceuticals from wastewater and source-separated urine

Recognizing the structural heterogeneity of Metal-N-C single atom catalysts (M-N-C SACs) and further revealing the impact of other metal phases that may be generated during the preparation process on the catalytic activity of SACs are essential for the rational design of M-N-C SACs. Through the post-Fe(III)-N coordination strategy, an extremely reactive heterogeneous Fe-N-C SACs including Fe-Nx coordinating sites and carbon-iron hybrids into the N-doped graphene-containing carbon nanoflakes (Fe3C/Fe-Nx@GCN) is designed at the atomic level. As a stabilized Fenton-like activator, the catalyst exhibits a high mass activity of 2.08 × 105 min−1 mol−1 for the catalytic oxidation of recalcitrant organic. The experiments and density functional theory (DFT) calculations reveal that specific type of N-coordinated Fe sites with a lower d-band center position is prone to Fe-oxo species production. However, the incorporation of carbon-iron hybrids induces charge redistribution in the active metal centers, further enhancing catalyst’s adsorption energy on peroxymonosulfate (PMS) and effectively modulating the reaction energy barriers. Additionally, the electron transfer pathway dominated by potential differences was confirmed by appropriate reactive substrate orbital energies. This study preferentially provides perspectives on the synergistic relationship between carbon-iron hybrids and Fe-Nx in PMS-AOPs and proposes the multiple-reaction pathways for eliminating pharmaceuticals from the source-separated urine.

Design of ZnFeAlO4/Zn-SAPO-34 composite catalyst for selective hydrogenation of CO2 to propane

Catalytic hydrogenation of CO2 into a single product provides a promising strategy for recycling and utilizing this greenhouse gas, but it remains challenge. Herein, a ZnFeAlO4/Zn-SAPO-34 composite catalyst has been designed, which exhibits a space-time yield of propane of 4.21 mmol g−1 h−1, along with a long-term stability of over 180 h. It was found that the Fe sites in ZnFeAlO4 spinel are conductive to accelerate CO2 hydrogenation into CH3OH, which are stable enough to prevent reduction and carbonization. Characterization results proved that more Brønsted acid sites of SAPO-34 and the addition of Zn species into SAPO-34 zeolite are favorable to form active methylbenzenes with four or five methyl groups, preferentially leading to the formation of propylene via the aromatics-based cycle, which could be hydrogenated to propane. This work presents a feasible strategy in designing an efficient composite catalyst for the synthesis of specific single products from CO2 hydrogenation.

Precisely Regulating Asymmetric Charge Distribution by Single-Atom Central Doped Ag-Based Series Clusters for Enhanced Photoreduction of CO2 to Alcohol Fuels.

High efficiently photocatalytic CO2 reduction (CO2RR) into liquid fuels in pure water system remains challenged. Iron polyphthalocyanine (FePPc) with strong light harvesting, unique Fe-N4 structure, abundant pores, and good stability could serve as a promising catalyst for CO2 photoreduction. To further improve the catalytic efficiency, herein, symmetry-breaking Fe sites are constructed by coupling with atomically precise M1Ag24 (M=Ag, Au, Pt) series clusters. Especially, the introduction of Pt1Ag24 causes the most asymmetric charge distribution of Fe in FePPc (followed by Au1Ag24 and Ag25), leading to the favorable CO2 adsorption and activation. In addition, Pt1Ag24-FePPc exhibits the most effective photogenerated carriers transfer and separation. As a result, Pt1Ag24-FePPc shows the methanol/ethanol yield of 48.55/32.97 μmol·gcat-1·h-1 in H2O-CO2 system under visible light irradiation, ~ 1.65/1.25-fold, 1.83/1.37-fold, and 3.6/1.61-fold higher than that of Au1Ag24-FePPc, Ag25-FePPc, and FePPc, respectively. This work provides a concept for precisely construction and regulation symmetry-breaking sites of cluster-based catalysts for effective CO2 conversion.

Eggshell membrane-derived electrocatalysts for water electrolysis

Green H2 (GH2) holds significant promise as a renewable energy resource, particularly in addressing the escalating energy demands sustainably. The imperative for economically viable GH2 technologies, primarily via water electrolysis, has spurred extensive research into suitable electrocatalytic materials. Eggshell membrane (ESM) is typically considered a biowaste material obtained from eggs, which are among the most widely consumed foods both domestically and industrially. Many countries legally require the effective treatment of ESM before disposal to prevent environmental contamination. Therefore, we propose upcycling ESM as an electrocatalytic support, forming transition metal-based active sites through chemical and thermal treatment, followed by doping highly reactive Fe sites electrochemically. ESM’s nanofibrous morphology and porous structure confer catalytic advantages. X-ray photoelectron spectroscopy analysis reveals that certain chemical functional groups in the ESM are involved in the spontaneous electrochemical charge transfer and the adsorption of metal ions, contributing to the formation of metal nanoparticles. Furthermore, various anionic chemical elements such as P, O, N, and S, which originate from intrinsic ESM, can participate in electrocatalysis. The Fe sites electrochemically induced on the Ni and Co nanoparticle surfaces in the ESMs demonstrate excellent electrocatalytic activity and durability toward the oxygen and hydrogen evolution reactions, respectively. This study provides a strategy to utilize ESM as an electrocatalytic material for the development of commercially viable electrocatalysts to produce GH2 by transforming biowaste into value-added materials. Moreover, it promotes the investigation of the (electro)chemical functionalities of biomaterials and the correlation between their functions and electrocatalytic activities.

UVA light assisted activation of sulfite by metal–organic framework-derived FeOx@C catalyst for organic degradation: Formation and role of non-radical species

Advanced oxidation processes (AOPs) based on sulfite (S(IV)) activation are gaining recognition as a promising Fenton-like strategy, primarily due to their ability to generate potent radicals (e.g., SO4− and HO). However, the existence and role of a non-radical-driven oxidation pathway in the S(IV)-mediated degradation of contaminants remain under debate. Herein, a magnetic iron-carbon composite (FeOx@C) was fabricated using the MOF-templated method and utilized as a stable photocatalyst to activate S(IV) under UVA light, achieving >93.6 % degradation of 20 μM ofloxacin (OFL) with a high degradation rate constant of 0.073 min−1 within 45 min. The catalyst’s porous carbon structure facilitated the transport of substrates to active sites and shortened the diffusion distance between reactive species and contaminants. Adsorbed S(IV) donated one electron to photo-generated holes and exposed Fe(III) sites with the formation of SO5−, which then followed two distinct pathways to produce radicals (SO4−) and non-radicals (Fe(IV) and 1O2) responsible for OFL degradation. By leveraging the synergy of both radicals and non-radicals, this innovative oxidative system showcased robust anti-interference capacities and exceptional performance in degrading contaminants from complex water matrices. This study provides new insights into the significant role of non-radical species in S(IV)-mediated decontamination processes.

Accelerating electron transfer dynamics for efficient nitrogen photoreduction on nitrogenase-mimicking metal-organic framework/Fe-dispersed MXene

Achieving efficient artificial nitrogen fixation similar to nitrogenase under mild conditions has always been a goal pursued by human beings, but it remains a huge challenge. Herein, a novel photothermal catalyst UiO-66(Zr-Fe)/Fe-dispersed MXene having nitrogenase-mimicking electron transfer structure and electron donation mechanism is fabricated and applied in a designed gas-vapor-solid bi-phase system for efficient N2-to-NH3 conversion. The complementary role playing of UiO-66(Zr-Fe), Ti3C2 MXene and well-dispersed Fe sites are capable of simulating nitrogenase triple tandem system that in charge of electron generation, electron transfer and N2 fixation, respectively. In this well-designed catalyst, a remarkably high NH3 formation rate of 133.2 μmol g−1 h−1 under solar level illumination is recorded. This superior performance of the biomimetic structure is related to the enhanced light-to-matter interaction for effective multi-electron extraction and promoted photothermal response for accelerating surface reaction dynamics.