Bimetallic Sites Research Articles

Cu-Fe bimetallic MOFs with long lifetime separated-state charge for enhancing selectivity for CO2 photoreduction to CH4

Improving the CO2 to CH4 conversion efficiency of Cu metal-organic frameworks (Cu-MOFs) catalysts is important for promoting carbon capture and utilization. In this work, a series of novel Cu-Fe bimetallic MOFs photocatalysts (Cu-BTB-Fe with 0.5 wt%, 1.0 wt%, 2.0 wt%, and 4.0 wt% of Fe; H3BTB = 1,3,5-tris(4-carboxyphenyl) benzene) were synthesized by a bimetallic site (Cu and Fe) design strategy in order to improve the electron-hole separation efficiency and CO2 adsorption activation. Findings indicated that the as-synthesized Cu-BTB-2 wt% Fe catalyst exhibited excellent catalytic performance for the conversion of CO2 to CH4 and CO under simulated sunlight irradiation, providing a yield of 32.20 μmol∙g−1∙h−1 and a selectivity of 69.24 % for CO2 to CH4 conversion as well as a yield of 14.29 μmol∙g−1∙h−1 for CO2 to CO conversion without liquid phase products. This is because the Cu-Fe bimetallic sites can continuously supply photoinduced electrons with long separated-state decay lifetime to efficiently activate CO2. Specifically, the Cu-BTB-Fe catalysts provided a high proportion of effective photoinduced electrons with long decay lifetime for the CO* hydrogenation process through a unique electron transfer mechanism, while the strong affinity between CO2 and [Cu2(COO)4]-Fe active units enabled high CO2 adsorption activation and rapid CO2 reduction. The present approach, hopefully, would help to establish feasible pathway for the development of novel highly selective Cu-based MOFs photocatalysts for CO2 photocatalytic reduction yielding CH4.

Assembly of MOFs derived Co-Mn bimetallic oxides on SiO2 nanofibrous membrane for indoor air purification

The development of highly efficient air purification materials contributes to acquiring quality indoor air that essential for improving physical health and life comfort. In this work, a Co3O4-CoMn2O4@SiO2 (COCMOS) nanofibrous membranes (NFMs) were prepared by thermal treating Mn-modified ZIF-67@SiO2 NFMs for efficient indoor air purification. The COCMOS NFMs exhibited 99.03 % and 99.999 % dust retention efficiencies for PM0.3 and PM2.5 with a low filtration resistance, respectively. Compared to the Co3O4@SiO2 (COS) NFMs (23 %), the HCHO removal efficiency of COCMOS NFMs was significantly improved at room temperature, reaching over 95 % within 25 min. The characterization results indicated that the thermal treatment of Mn-modified ZIF-67 induced the formation of a Co3O4-CoMn2O4 heterostructure on the surface of COCMOS NFMs. The Mn-Co bimetallic sites in this heterogeneous structure increased the amounts of oxygen vacancies and high valent cations and enhanced the redox properties of COCMOS NFMs, which contributed to its superior performance. This work provided insights on the design and preparation of highly efficient materials for indoor air purification.

Exploring the catalytic characteristics of binuclear bimetallic FeM sites (M = Co, Ni, Pt) on nitrogen-doped graphene through density functional theory and ab initio molecular dynamics

Certain supported bimetallic catalysts exhibit high efficiency in both oxygen reduction reactions (ORR) and oxygen evolution reactions (OER). However, the catalytic mechanism of double-atom catalysts and how different-atom active sites affect charge transfer efficiency have not been fully revealed. In this work, we provide density functional theory (DFT) simulations of ORR/OER on FeM-NC (M = Co, Ni, Pt) supported on nitrogen-doped graphene. The stability of structures, electrical properties, adsorption energies of intermediates, and catalytic activity of ORR/OER on FeM-NC have been investigated. The results indicate that the Fe-atom in stable FeM-NC structures is a catalytically active site and that the FeM-NC-1 structures may be more appropriate as catalysts. The overpotentials for ORR/OER on FeM-NC-1 (M = Co, Ni, Pt) are 0.42/0.29 V on FeCo-NC-1, 0.57/0.33 V on FeNi-NC-1, and 0.64/0.33 V on FePt-NC-1, which is significantly lower than those on Pt(111) surfaces. Ab initio molecular dynamics (AIMD) simulations suggest that ORR/OER may occur vis a typical four-electron mechanism on FeNi-NC-1 and FePt-NC-1 configurations, while on FeCo-NC-1 structures, it may involve two different four-electron pathways. This study increases our knowledge of the structural stability of FeM-NC-1 structures as bifunctional catalysts and the ORR/OER pathway in acidic solution, and it also shows that three FeM-NC-1 structures are suitable candidate catalysts for ORR/OER.

Cascade Electrocatalytic Reduction of Nitrate to Ammonia Using a Heterobimetallic Covalent Organic Framework Composed of Cu-Porphyrin and Co-Bipyridine.

The electrocatalytic reduction of nitrate (NO3-) to ammonia (NH3) not only offers an effective solution to environmental problems caused by the accumulation of NO3- but also provides a sustainable alternative to the Haber-Bosch process. However, the conversion of NO3- to NH3 is a complicated process involving multiple steps, leading to a low Faradaic efficiency (FE) for NH3 production. The structural designability of covalent organic frameworks (COFs) renders feasible and precise modulation at the molecular level, facilitating the incorporation of multiple well-defined catalytic sites with different reactivities into a cohesive entity. This promotes the efficiency of the overall reaction through the coupling of multistep reactions. Herein, heterobimetallic CuP-CoBpy was prepared by postmodification, involving the anchoring of cobalt ions to the CuP-Bpy structure. As a result of the cascade effect of the bimetallic sites, CuP-CoBpy achieved an outstanding NH3 yield of 13.9 mg h-1 mgcat.-1 with a high FE of 96.7% at -0.70 V versus the reversible hydrogen electrode and exhibited excellent stability during catalysis. A series of experimental and theoretical studies revealed that the CuP unit facilitates the conversion of NO3- to NO2-, while the CoBpy moiety significantly prompts the reduction of NO2- to NH3. This study demonstrates that tailoring the structural units for the construction of COFs based on each step in the multistep reaction can enhance both the catalytic activity and product selectivity of the overall process.

Photothermal effect improving the activity of spinel MnFe2O4 nanoparticles for the catalytic activation HCO3−/H2O2 to achieve the degradation of dye pollutants in low-temperature condition

Based on the features of Mn/Fe bimetallic sites and photothermal property, spinel MnFe2O4 nanoparticles were investigated to activate HCO3−/H2O2 for the degradation of methyl orange (MO), methylene blue (MB) and rhodamine B (RhB). Compared to Mn3O4, MnO2 and Fe2O3- activated HCO3−/H2O2 systems, higher degradation rate of dyes was achieved in the spinel MnFe2O4/HCO3−/H2O2 system at 23 ± 2 °C, due to the Mn/Fe bimetallic active sites of spinel MnFe2O4. Meanwhile, the spinel MnFe2O4 nanoparticles had high stability in HCO3−/H2O2 activating for dyes degradation in 15 rounds of reaction. The co-existing ions and hardness in municipal tap water had weak influence on the HCO3−/H2O2 activating activity of spinel MnFe2O4 for dyes degradation at 23 ± 2 °C. More interestingly, although the dyes degradation activity of MnFe2O4/HCO3−/H2O2 system at low-temperature (3 ± 2 °C or 13 ± 2 °C) was weakened, the system activity at low-temperature can be obviously boosted through AM 1.5 G irradiation to activate the photothermal effect of spinel MnFe2O4. Additionally, the MnFe2O4/HCO3−/H2O2 system exhibited good practicability for dyes degradation in a 15 L of continuous reactor. In mechanism, the degradation of MB in spinel MnFe2O4/HCO3−/H2O2 system was found to be co-driven by 1O2 and OH, and the degradation of RhB and MO was co-initiated by O2−, OH and CO3−.

Synergistic effect of Fe-Mn bimetallic sites with close proximity for enhanced CO2 hydrogenation performance

Synergistic effect of Fe-Mn bimetallic sites with close proximity for enhanced CO2 hydrogenation performance

Regulation of asymmetric bimetallic NiFe sites boost fast desolvation kinetics for long-cycling ammonium-ion storage

Aqueous ammonium ion battery (AAIB) is a new type of energy storage device with non-metallic ion (NH4+) as the carrier, possessing the apparent advantages of low cost, high safety, and long-term sustainability. However, the sluggish kinetics of the electrolyte-electrode interface often results in a slow NH4+ transport within the host structure, leading to poor cycling stability, especially in the type of cathode material with open frameworks represented by Fe-based Prussian blue analogues (PBAs). In this work, a NiFe-PBA (NiFe) cathode material with asymmetric bimetallic sites is purposely designed to regulate and improve the NH4+ desolvation kinetics at the electrolyte-electrode interface. Theoretical simulations first reveal that regulating the asymmetric bimetallic site effectively reduces the energy barrier of NH4+(H2O)4 desolvation at the electrolyte-electrode interface, and thus the NH4+(H2O)4 can be desolvated into NH4+ into host material. The electrochemical study results further show that the successful introduction of asymmetric bimetallic sites largely improves the diffusion kinetics and structural stability of FeFe-PBA (FeFe), realizing stable cycling performance (97 % retention after 700 cycles at 0.25 A g−1) and high-rate capability. Finally, in-situ characterizations in combination with theoretical calculations demonstrate that the insertion/extraction of NH4+ is attributed to the charge storage mechanism of reversible interactions in association with the coordination of N atoms in the NiFe-PBA.

Bimetal-carbon engineering for polypropylene conversion into hydrocarbons and ketones in a Fenton-like system

Fenton-like reaction with targeted reactive species was tested for up-cycling of waste plastics to value-added chemicals and we demonstrated a bimetal-carbon-activated peroxymonosulfate (PMS) Fenton-like system for effectively converting polypropylene into hydrocarbons and ketones. In a hydrothermal reaction process at 160 °C for 14 h, directional polypropylene conversion was achieved at a selectivity of 80 wt% hydrocarbons and ketones in the products. The distribution of Cu-Mg bimetallic sites on a carbon substrate exhibited a synergistic effect, and their catalytic activation of PMS induced specific generation of •OH-dominated reactive species. The target reactive species controlled the oxidizing capacity of the system. The efficient breaking of C-C/C-H bond in polypropylene and the subsequent further oxidation under mild conditions led to the dominated products of hydrocarbons and ketones. This study provides an attractive approach for upcycling waste plastics, thus promoting circular economy and carbon reduction.

Efficient Electrosynthesis of Urea over Single-Atom Alloy with Electronic Metal Support Interaction.

Urea electrosynthesis from carbon dioxide (CO2) and nitrate (NO3 -) is an alternative approach to traditional energy-intensive urea synthesis technology. Herein, we report a CuAu single-atom alloy (SAA) with electronic metal support interaction (EMSI), achieving a high urea yield rate of 813.6 μg h-1 mgcat -1 at -0.94 V versus reversible hydrogen electrode (vs. RHE) and a Faradaic efficiency (FE) of 45.2 % at -0.74 V vs. RHE. In situ experiments and theoretical calculations demonstrated that single-atom Cu sites modulate the adsorption behavior of intermediate species. Bimetallic sites synergistically accelerate C-N bond formation through spontaneous coupling of *CO and *NO to form *ONCO as key intermediates. More importantly, electronic metal support interaction between CuAu SAA and CeO2 carrier further modulates electron structure and interfacial microenvironment, endowing electrocatalysts with superior activity and durability. This work constructs SAA electrocatalysts with EMSI effect to tailor C-N coupling at the atomic level, which can provide guidance for the development of C-N coupling systems.

Ni–Ca metastable–nonmetastable bimetallic sites induced ·OH directed generation and efficient water purification

AbstractStrongly oxidizing ·OH can non‐selectively degrade various organic pollutants, but how to selectively generate ·OH is a great challenge. In this study, the directed generation of ·OH was achieved based on Ni–Ca metastable–nonmetastable bimetallic sites, Ni2+/Ni3+ valence cycling provided electrons for ·OH generation induced by the non‐variable Ca‐based sites, which constructed a nearly 100% selective generation pathway of ·OH (O3 → HO3/HO2 → OH). The antibiotic pefloxacin could be completely removed in 15 min, and the COD removal efficiency for other hard‐to‐degrade pollutants such as oxalic acid and chlorobenzoic acid could reach more than 90%. Ni doping significantly increased the oxygen vacancy and Lewis acid content, and DFT calculations showed that Ni–Ca dual‐site had a lower reaction energy barrier and the complexed hydroxyl radical intermediate *OO had a higher spin density (−0.6), which was more favorable for the generation of ·OH. Therefore, this study provides new ideas for efficient treatment of actual wastewater.

Efficient Electrosynthesis of Urea over Single‐Atom Alloy with Electronic Metal Support Interaction

AbstractUrea electrosynthesis from carbon dioxide (CO2) and nitrate (NO3−) is an alternative approach to traditional energy‐intensive urea synthesis technology. Herein, we report a CuAu single‐atom alloy (SAA) with electronic metal support interaction (EMSI), achieving a high urea yield rate of 813.6 μg h−1 mgcat−1 at −0.94 V versus reversible hydrogen electrode (vs. RHE) and a Faradaic efficiency (FE) of 45.2 % at −0.74 V vs. RHE. In situ experiments and theoretical calculations demonstrated that single‐atom Cu sites modulate the adsorption behavior of intermediate species. Bimetallic sites synergistically accelerate C−N bond formation through spontaneous coupling of *CO and *NO to form *ONCO as key intermediates. More importantly, electronic metal support interaction between CuAu SAA and CeO2 carrier further modulates electron structure and interfacial microenvironment, endowing electrocatalysts with superior activity and durability. This work constructs SAA electrocatalysts with EMSI effect to tailor C−N coupling at the atomic level, which can provide guidance for the development of C−N coupling systems.

NiMoO4 containing O-vacancy cooperated with bimetallic sulfides as efficient bifunctional electrocatalyst for overall water splitting

MoS2 is a potential transition metal sulfide (TMS) with excellent performance for hydrogen evolution reaction (HER) in acidic medium. However, MoS2 has poor stability owing to its metastable properties and therefore is easily oxidized to MoO3 which can hinder the HER process. In this work, MoO3 on the surface of the TMS is transformed to NiMoO4 with plentiful oxygen vacancies (Ov) favorable for HER and oxygen evolution reaction (OER) by an acid treatment to form an Ov-containing transition bimetallic sulfide/oxide catalyst (Ov-NiMoO4@Ni3S2-MoS2-rGO-NF, denoted as NiMoO4@NiMoS-rN). The electrocatalyst shows exceptional performance for HER and OER in terms of increased intrinsic activity, electron transfer efficiency, reaction kinetics and durability on account of the Ov, synergistic effect among different phases and bimetallic active sites. The overpotentials of NiMoO4@NiMoS-rN electrode when achieving 10 mA cm−2 are 45 mV and 195 mV towards HER and OER in alkaline, respectively, and the performance holds nearly unchanged during a 50-h stability test. When assembled to a two-electrode system, the current density of 10 mA cm−2 can keep steady for 50 h without degradation. The strategy combined by phase transition, interface and defect engineering via a facile method provides a practical idea for design and modulation of bifunctional electrocatalysts.

Dual-Atom P-Co-Dy Charge-Transfer Bridge on Black Phosphorus for Enhanced Photocatalytic CO2 Reduction.

The synergistic effect of rare earth single-atoms and transition metal single-atoms may enable us to achieve some unprecedented performance and characteristics. Here, Co-Dy dual-atoms on black phosphorus with a P-Co-Dy charge-transfer bridge are designed and fabricated as the active center for the CO2 photoreduction reaction. The synergistic effect of Co-Dy on the performance of black phosphorus is studied by combining X-ray absorption spectroscopy, ultrafast spectral analysis, and in situ technology with DFT calculations. The results show that the Co and Dy bimetallic active site can promote charge transfer by the charge transfer bridge from P to Dy, and then to Co, thereby improving the photocatalytic activity of black phosphorus. The performance of catalysts excited at different wavelength light indicates that the 4G11/2/2I15/2/4F9/2→6H15/2 and 4F9/2→6H13/2 emissions of Dy can be absorbed by black phosphorus to improve the utilization of sunlight. The in situ DRIFTS and density functional theory (DFT) calculations are used to investigate the CO2 photoreduction pathway. This work provides an depth insight into the mechanism of dual-atom catalysts with enhanced photocatalytic performance, which helps to design novel atomic photocatalysts with excellent activity for CO2 reduction reactions.

Ionic Liquids Boost Anthraquinone Hydrogenation over Pd‐based Bimetallic Pincer Catalysts

AbstractA series of bimetallic‐ionic liquid (IL) pincer catalysts Pd−M@IL were synthesized using low Pd‐loading amount (0.3 %) and adopting six kinds of ion liquids with the cation containing the imidazole ring, and then evaluated the catalytic activities toward 2‐ethylanthraquinone hydrogenation reaction with the purpose to produce H2O2. Under the reaction conditions of 60 °C, 0.30 MPa and 15 min reaction time, over the catalysts Pd−La@[BMIm]Ac/alu and Pd−La@[VBIM]Br/alu achieved high hydrogenation efficiency(9.4 g/L and 8.5 g/L) but also high selectivity toward the active anthraquinone (98.9 % and 99.6 %). Through characterizations of STEM, TPD, in‐situ XPS, etc., it illustrates that the pincer catalysts Pd−La@[BMIm]Ac/alu and Pd−La@[VBIM]Br/alu have much better dispersity than the bimetallic Pd−La/alu, these two ionic liquids of [BMIm]Ac and [VBIM]Br provide different local environment around Pd−La sites, which in turn modulate the catalytic activity of the pincer‐catalysts toward anthraquinone hydrogenation. DFT calculations disclose the unique electron transfer between ILs ([BMIm]Ac and [VBIM]Br) and Pd−La clusters and subsequent changes of energy barriers for anthraquinone hydrogenation. The work illuminates a facile strategy to design novel hydrogenation catalysts through combining the pincer microenvironment partially encapsulated by the cation and the anion of ionic liquids with the internal bimetallic sites.

Sulfur-Bridged Asymmetric CuNi Bimetallic Atom Sites for CO2 Reduction with High Efficiency.

Double-atom catalysts (DACs) with asymmetric coordination are crucial for enhancing the benefits of electrochemical carbon dioxide reduction and advancing sustainable development, however, the rational design of DACs is still challenging. Herein, this work synthesizes atomically dispersed catalysts with novel sulfur-bridged Cu-S-Ni sites (named Cu-S-Ni/SNC), utilizing biomass wool keratin as precursor. The plentiful disulfide bonds in wool keratin overcome the limitations of traditional gas-phase S ligand etching process and enable the one-step formation of S-bridged sites. X-ray absorption spectroscopy (XAS) confirms the existence of bimetallic sites with N2Cu-S-NiN2 moiety. In H-cell, Cu-S-Ni/SNC shows high CO Faraday efficiency of 98.1% at -0.65V versus RHE. Benefiting from the charge tuning effect between the metal site and bridged sulfur atoms, a large current density of 550mAcm-2 can be achieved at -1.00V in flow cell. Additionally, in situ XAS, attenuated total reflection surface-enhanced infrared absorption spectroscopy (ATR-SEIRAS), and density functional theory (DFT) calculations show Cu as the main adsorption site is dual-regulated by Ni and S atoms, which enhances CO2 activation and accelerates the formation of *COOH intermediates. This kind of asymmetric bimetallic atom catalysts may open new pathways for precision preparation and performance regulation of atomic materials toward energy applications.

Mesoporous amorphous non-noble metals as versatile substrates for high loading and uniform dispersion of Pt-group single atoms.

Atomically dispersed Pt-group metals are promising as nanocatalysts because of their unique geometric structures and ultrahigh atomic utilization. However, loading isolated Pt-group metals in single-atom alloys (SAAs) with distinctive bimetallic sites is challenging. In this study, we present amorphous mesoporous Ni boride (Ni-B) as an ideal substrate to uniformly disperse Pt atoms with tunable loadings (1.7 to 12.2 wt %). The effect of the morphology, composition, and crystal phase of the Ni-B host on the growth and dispersion of Pt atoms is discussed. The resulting amorphous Pt-Ni-B mesoporous nanospheres exhibit superior electrocatalytic H2 evolution performance in acidic media. This strategy holds the potential to synthesize a diverse library of mesoporous amorphous Pt-group SAAs, by leveraging functional amorphous nanostructured 3d transition-metal borides as substrates, thereby proposing a comprehensive strategy to control atomically dispersed Pt-group metals.

Overcome the trade-off in electro-fenton chemistry for in situ H2O2 generation-activation by tandem CoFe bimetallic single-atom configuration

Dual-atomic catalysts (DACs) demonstrated remarkable potential in addressing key challenges in electro-Fenton (EF) processes. In this study, we synthesized an EF DACs comprising both CoN4 and FeN4 sites, which was achieved a high H2O2 generation rate (1.68 mM−1h−1) and 100 % bisphenol A degradation efficiency via successive two-electron oxygen reduction and one-electron Fenton reactions (2e− ORR + 1e− Fenton). Our findings indicated that the single-atom nitrogen coordination of CoN4 and FeN4 sites plays crucial roles in regulating the adsorption of key intermediates of *OOH and *H2O2. The bimetallic sites independently regulated the binding energies of *OOH on CoN4 (pyrrole-type) for favorable H2O2 generation and its subsequent activation on adjacent FeN4 (pyridine-type). Thus, the dual-site engineering addresses the trade-off of in situ H2O2 generation-activation in EF chemistry, realizing high electron utilization efficiency and fast pollutant degradation toward efficient and sustainable water treatment.

A Sunlight-Driven Self-Cleaning CuCo-MOF Composite Membrane for Highly Efficient Emulsion Separation and Water Purification.

The fouling phenomenon of membranes has hindered the rapid development of separation technology in wastewater treatment. The integration of materials into membranes with both excellent separation performance and self-cleaning properties still pose challenges. Here, a self-assembled composite membrane with solar-driven self-cleaning performance is reported for the treatment of complex oil-water emulsions. The mechanical robustness of the composite membrane is enhanced by the electrostatic attraction between chitosan and metal-organic frameworks (MOF) CuCo-HHTP as well as the crosslinking effect of glutaraldehyde. Molecular dynamics (MD) simulations also revealed the hydrogen bonding interaction between chitosan and CuCo-HHTP. The composite membrane of CuCo-HHTP-5@CS/MPVDF exhibits a high flux ranging from 700.6 to 2350.6 L∙m-2∙h-1∙bar-1 and excellent separation efficiency (>99.0%) for various oil-water emulsions, including crude oil, kerosene, and other light oils. The addition of CuCo-HHTP shows remarkable photothermal effects, thus demonstrating excellent solar-driven self-cleaning capability and antibacterial performance (with an efficiency of ≈100%). Furthermore, CuCo-HHTP-5@CS/MPVDF can activate peroxomonosulfate (PMS) under sunlight, quickly removing oil-fouling and dyes. Density functional theory (DFT) calculations indicate that the bimetallic sites of Cu and Co in CuCo-HHTP effectively promoted the activation of PMS. This study provides distinctive insights into the multifaceted applications of MOFs-derived photothermal anti-fouling composite membranes.

Partially amorphization induced S-scheme charge migration in g-C3N4/Mn1.1Fe1.9O4 defective heterojunction for boosting fenton-like degradation of tetracycline under visible light

S-scheme photo-Fenton catalyst is promising in water purification, whereas its rational design and carrier transfer mechanism remain a challenge. Here, a novel defective heterojunction via combining g-C3N4 with amorphous/crystalline Mn1.1Fe1.9O4 (Mn1.1Fe1.9O4-a/c) is fabricated for the degradation of tetracycline. The rich oxygen defects introduced by partially amorphization strategy can regulate the work function of Mn1.1Fe1.9O4-a/c, and switch the charge transfer path of g-C3N4/Mn1.1Fe1.9O4 from type-II to S-scheme, which demonstrates by ultraviolet photoelectron spectroscopy, in-situ kelvin probe force microscopy and density functional theory calculations. Driven by internal electron field, photogenerated electrons can transfer from Mn1.1Fe1.9O4-a/c to g-C3N4, which accelerated the separation of photoexcited carriers and H2O2 activation. Benefiting from the accelerated redox conversion with the action of bimetallic sites, oxygen defects and electrons, the g-C3N4/Mn1.1Fe1.9O4-a/c photocatalyst achieves 94.7 % tetracycline removal within 60 min, and the normalized kinetic rate exceeds reported works by 1–2 orders of magnitude. Multiple synergistic pathways lead to more reactive oxygen species generation, which achieves efficient mineralization of tetracycline (79.9 %). This work provides a simple partially amorphization strategy to switch charge transfer pathway from type-II to S-scheme for efficient water purification.

Bimetallic MOF‐Based Fibrous Device for Noninvasive Bilirubin Sensing

AbstractNoninvasive and real‐time detection of bilirubin concentration enables rapid assessment of liver health status and the diagnosis of jaundice‐related diseases. Herein, the study proposes a strategy to uniformly grow bimetallic FeCo metal–organic framework (MOF) films onto the surface of carbonized electrospun nanofibers via a stepwise growth strategy involving an induction effect of oxide nanomembrane prepared by atomic layer deposition, to realize high‐performance flexible nanofiber bilirubin sensors. Compared with monometallic MOF, the FeCo bimetallic MOF can attain a larger specific surface area, thus augmenting the exposed active sites. Furthermore, the synergistic interaction between the bimetallic active sites on the MOF film and the carbonized nanofibers enhances the electronic conduction network, thereby significantly enhancing the catalytic activity of the flexible electrode for bilirubin. The current nanofibers sensor exhibits excellent performance in bilirubin detection, in terms of high sensitivity, large linear detection range, and low detection limit. The synthesis of bimetallic MOF films on flexible fibers holds promise for the development of highly sensitive electrodes for wearable bilirubin detection devices.