Heterointerface Engineering Research Articles

Tailoring Hydrogen Adsorption via Charge Transfer at Bimetallic Cr0.48Ru0.52 Alloy Nanoparticles Decorated on Carbon Nanofiber for Enhanced Hydrogen Evolution Catalysis

Designing and synthesizing highly efficient and stable electrocatalysts for the hydrogen evolution reaction (HER) is crucial for the practical and large-scale application of hydrogen sources. Recent research has focused on tuning the electronic structure of electrocatalysts to achieve optimal HER activity, with particular emphasis on interfacial engineering to induce electron transfer and optimize HER kinetics. In this study, as part of research into heterointerface engineering, bimetallic Cr0.48Ru0.52 alloy nanoparticles decorated on carbon nanofibers (Cr0.48Ru0.52/CNFs) were fabricated through a simple electrospinning and post-calcination process to serve as an efficient alkaline HER catalyst. The Cr0.48Ru0.52/CNFs demonstrated exceptional electrocatalytic HER performance, with an overpotential of only 13 mV at −10 mA cm−2 and a Tafel slope of 60.8 mV dec−1, indicating high catalytic activity compared to commercial benchmark catalysts (i.e., Ru/C and Pt/C). First-principles density functional theory calculations support these results, revealing that Cr0.48Ru0.52 balances proton reduction (Volmer step) and H* desorption (Tafel/Heyrovsky step) processes during electrocatalysis, as evidenced by the near-zero hydrogen adsorption (ΔGH*) value (ca. −0.11 eV). Therefore, this study highlights that Cr0.48Ru0.52/CNFs, with noble Ru comprising only half of the total metal content, can promote optimal HER kinetics under alkaline condition.

A High-Rate and Ultrastable Re2Te5/MXene Anode for Potassium Storage Enabled by Amorphous/Crystalline Heterointerface Engineering.

The pursuit of anode materials capable of rapid and reversible potassium storage performance is a challenging yet fascinating target. Herein, a heterointerface engineering strategy is proposed to prepare a novel superstructure composed of amorphous/crystalline Re2Te5 anchored on MXene substrate (A/C-Re2Te5/MXene) as an advanced anode for potassium-ion batteries (KIBs). The A/C-Re2Te5/MXene anode exhibits outstanding reversible capacity (350.4 mAh g-1 after 200 cycles at 0.2 A g-1), excellent rate capability (162.5 mAh g-1 at 20 A g-1), remarkable long-term cycling capability (186.1 mAh g-1 at 5 A g-1 over 5000 cycles), and reliable operation in flexible full KIBs, outperforming state-of-the-art metal chalcogenides-based devices. Experimental and theoretical investigations attribute this high performance to the synergistic effect of the A/C-Re2Te5 with a built-in electric field and the elastic MXene, enabling improved pseudocapacitive contribution, accelerated charge transfer behavior, and high K+ ion adsorption/diffusion ability. Meanwhile, a combination of intercalation and conversion reactions mechanism is observed within A/C-Re2Te5/MXene. This work offers a new approach for developing metal tellurides- and MXene-based anodes for achieving stable cyclability and fast-charging KIBs.

Modulation Strategies for Improving Electrocatalytic Performance of Transition Metal Phosphides

AbstractWith growing concerns regarding global warming and the depletion of fossil fuel resources, there is an increasingly urgent demand for electrochemical energy storage and conversion technologies, including zinc‐air batteries, fuel cells, and integrated water splitting systems. The development of cost‐effective and efficient electrocatalysts is pivotal to the commercial viability of electrocatalytic technologies related to energy. Transition metal phosphides (TMPs) have emerged as promising electrocatalysts in the energy sector owing to their adjustable electronic structure, abundant availability, and distinctive physicochemical properties. Modification of transition metal phosphides can be expected to result in enhanced catalytic performance. In this paper, several commonly employed strategies for improving performance including elemental doping, M/P stoichiometric ratios tuning, vacancy engineering, heterointerface engineering and carbon materials incorporation, which are of reference value for promoting the development of TMPs electrocatalysts and constructing highly active TMPs electrocatalysts to solve a variety of energy and environmental problems.

Promoting Reaction Kinetics and Boosting Sodium Storage Capability via Constructing Stable Heterostructures for Sodium‐Ion Batteries

AbstractConstructing heterostructures containing multiple active components is proven to be an efficient strategy for enhancing the sodium storage capability of anode materials in sodium‐ion batteries (SIBs). However, performance enhancement is often attributed to the unclear synergistic effects among the active components. A comprehensive understanding of the reaction mechanisms on the interfaces at the atomic level remains elusive. Herein, the carbon‐coated Fe3Se4/CoSe (Fe3Se4/CoSe‐C) anode material as a model featuring atomic‐scale contact interfaces is synthesized. This unique heterogeneous architecture offers an adjustable electronic structure, which facilitates rapid reaction kinetics and enhances structural integrity. In situ microscopic and ex situ spectral characterization techniques, along with theoretical simulations, confirm that the heterointerface with strong electric fields promotes Na+ ion migration. Based on solid‐state nuclear magnetic resonance (NMR) analysis, an interface charge storage mechanism is revealed, resulting in the enhanced specific capacity of the anode materials. When employed as an anode in SIBs, the Fe3Se4/CoSe‐C electrode demonstrates excellent rate capabilities (218 mAh g−1 at 7 A g−1) and prolonged cycling stability (258 mAh g−1 at 5 A g−1 after 1000 cycles). This work highlights the significance of heterointerface engineering in electrode material design for rechargeable batteries.

Heterointerface engineering of CoO/Co with ordered carbon for synergistic magnetoelectric coupling to enhance wideband microwave absorption

Highly developed electronic information technology has undoubtedly resulted in numerous benefits to the military and public life. However, the resulting electromagnetic wave (EW) pollution cannot be ignored. Therefore, the application of highly efficient EW materials is becoming an important requirement. In this study, magnetic-dielectric heterointerface strategy was applied to construct absorbers with desirable electromagnetic wave properties. A novel CoO/Co nanoparticle anchored to N-doped mesoporous carbon (CoO/Co/N-CMK-3) composites was fabricated by facile precipitation reaction and the electromagnetic characteristics have been well optimized by adjusting pyrolysis temperature. The CoO/Co/N-CMK-3 yielded its highest performance at an annealing temperature of 800 °C, with an extended effective absorption bandwidth of 5.83 GHz and unusually low minimum reflection loss of−63.82 dB, even at a thickness of just 1.8 mm and low filler loading (10 %). For the excellent microwave absorption property, the advantages of the CoO/Co/N-CMK-3 can be summed up as follows. Firstly, the incorporation of heterointerfaces among N-CMK-3, CoO, and Co introduces abundant polarization centers, triggering various polarization effects and increasing dielectric losses. Secondly, the CoO/Co magnetic component introduced the strong magnetic loss and improved the impedance matching capability of CoO/Co/N-CMK-3. Thirdly, the extraordinary magnetic-dielectric behavior is supported by multiple magnetic coupling networks and enriched air-material heterointerfaces, boosted the magnetoelectric cooperative loss for further optimizing the electromagnetic dissipation and broadening the effective absorption frequency band. Moreover, the CST simulation results validate the impressive operational bandwidth and reflection loss characteristics of the obtained absorbers. This study demonstrates a novel heterointerface engineering strategy for designing lightweight, wide-band, and high-performance EW absorbers.

Engineering a Ce Promoter into a Three-Dimensional Porous Mo2C@NC Heterostructure for Hydrogen Evolution Electrocatalysis via Weakening the Mo-H Bond Strength.

The pursuit of highly efficient electrocatalysts for the alkaline hydrogen evolution reaction (HER) is of paramount importance for water splitting. However, it is still a formidable task in Mo2C-based materials because of the agglomeration and strong Mo-H binding of Mo2C units. Herein, a novel CeOCl-CeO2/Mo2C heterostructure nesting within a three-dimensional porous nitrogen-doped carbon matrix has been designed and used for catalyzing HER via simultaneous morphology and heterointerface engineering. As expected, the optimal CeOCl-CeO2(0.2)/Mo2C@3DNC exhibits impressive HER activity, with a low overpotential of 156 mV at a current density of 10 mA cm-2 coupled with a slight Tafel slope of 62.20 mV dec-1. Introducing a Ce promoter, that is CeOCl and CeO2, would endow the interface with an internal electric field and electron redistribution between CeOCl-CeO2 and Mo2C induced by the heterogeneous work function difference. Moreover, experimental investigation and density functional calculations confirm that the CeOCl-CeO2/Mo2C heterointerface can downshift the d-band center of the active Mo center, weakening the strength of the Mo-H coupling. This proposed concept, engineering Ce-based promoters into active entities involved in the heterostructure to modulate intermediate adsorption, offers a great opportunity for the design of superior electrocatalysts for energy conversion.

Heterointerface engineering of yolk-shell-structured Mn2O3/RuO2 for boosting oxygen electrocatalysis in rechargeable liquid and flexible zinc-air batteries

Rational construction of high-efficient bifunctional oxygen electrocatalysts is of crucial significance for rechargeable Zn-air batteries (ZABs). Here, the yolk-shell-structured Mn2O3/RuO2 heterojunction is purposely constructed via the Kirkendall effect as a robust bifunctional oxygen electrocatalyst for simultaneously driving oxygen evolution and reduction reactions (OER and ORR). The strong interactions between Mn2O3 and RuO2 induces the surface reconstruction that brings the electronic transfer from Mn to Ru, and the changes of coordination environments of metal atoms. Meanwhile, the yolk-shell structure enables maximum contact of the active sites with the electrolyte and prevents the dissolution and peroxidation of active species. As a result, the yolk-shell-structured Mn2O3/RuO2 shows an outstanding bifunctional activity with a very low potential gap of ΔE = 0.60 V. Moreover, the ZABs assembled with Mn2O3/RuO2 render a large open circuit voltage of 1.53 V, a high specific capacity of 742.1 mA h g−1 and an exceptional cycling stability over 850 h that significantly outperforms those of Pt/C+RuO2-based ZABs. Moreover, the self-made flexible solid-state ZAB with Mn2O3/RuO2 cathode also shows good charge–discharge reversibility and flexibility at different bending angles. This work provides a feasible method for the design of efficient oxygen electrocatalysts to promote the practical application of ZABs.

Embedded Hybrid-Dimensional Heterointerface for Filament Modulation in 2D Material-Based Artificial Nociceptor.

Nociceptors are key sensory receptors that transmit warning signals to the central nervous system in response to painful stimuli. This fundamental process is emulated in an electronic device by developing a novel artificial nociceptor with an ultrathin, nonstoichiometric gallium oxide (GaOx)-silicon oxide heterostructure. A large-area 2D-GaOx film is printed on a substrate through liquid metal printing to facilitate the production of conductive filaments. This nociceptive structure exhibits a unique short-term temporal response following stimulation, enabling a facile demonstration of threshold-switching physics. The developed heterointerface 2D-GaOx film enables the fabrication of fast-switching, low-energy, and compliance-free 2D-GaOx nociceptors, as confirmed through experiments. The accumulation and extrusion of Ag in the oxide matrix are significant for inducing plastic changes in artificial biological sensors. High-resolution transmission electron microscopy and electron energy loss spectroscopy demonstrate that Ag clusters in the material dispersed under electrical bias and regrouped spontaneously when the bias is removed owing to interfacial energy minimization. Moreover, 2D nociceptors are stable; thus, heterointerface engineering can enable effective control of charge transfer in 2D heterostructural devices. Furthermore, the diffusive 2D-GaOx device and its Ag dynamics enable the direct emulation of biological nociceptors, marking an advancement in the hardware implementation of artificial human sensory systems.

Nano‐Single‐Atom Heterointerface Engineering for pH‐Universal Electrochemical Nitrate Reduction to Ammonia

AbstractNano‐single‐atom‐catalysts have the potential to combine the respective advantages of both nano‐catalysts and single‐atom‐catalysts and thus exhibit enhanced performance. Generally, the separation of active sites in space limits the interaction between single atoms and nanoparticles. Heterointerface engineering has the potential to break this limitation. Regretfully, studies on the interface effect between single atoms and nanoparticles are rarely reported. Herein, an unprecedented nano‐single‐atom heterointerface composed of Fe single‐atoms and carbon‐shell‐coated FeP nanoparticles (Fe SAC/FeP@C) is demonstrated as an efficient electrocatalyst for the nitrate reduction process from alkaline to acidic. Compared with typical nano‐single‐atom‐catalysts (Fe SAC/FePO4) and single‐atom‐catalysts (Fe SAC), the constructed Fe SAC/FeP@C heterostructure exhibits dramatically enhanced nitrate‐to‐ammonia performance. Especially in acidic media, the maxmium Faradaic efficiency of ammonia (NH3) can reach 95.6 ± 0.5%, with a maximum NH3 yield of 36.2 ± 3.1 mg h−1 mgcat−1 (pH = 1.2), which is considerably higher than previously reported. Density functional theory calculations and in situ spectroscopic investigations indicate that the unique charge redistribution at the interface, together with the optimized electronic structure of Fe single‐atoms, strengthens intermediate adsorption and catalytic activity. This work provides a feasible strategy for designing nano‐single‐atom‐catalysts with unique heterointerfaces, as well as valuable insights into nitrate conversion under environmentally relevant wastewater conditions.

In Situ Encapsulation of SnS2/MoS2 Heterojunctions by Amphiphilic Graphene for High-Energy and Ultrastable Lithium-Ion Anodes.

Lithium-ion batteries with transition metal sulfides (TMSs) anodes promise a high capacity, abundant resources, and environmental friendliness, yet they suffer from fast degradation and low Coulombic efficiency. Here, a heterostructured bimetallic TMS anode is fabricated by in situ encapsulating SnS2/MoS2 nanoparticles within an amphiphilic hollow double-graphene sheet (DGS). The hierarchically porous DGS consists of inner hydrophilic graphene and outer hydrophobic graphene, which can accelerate electron/ion migration and strongly hold the integrity of alloy microparticles during expansion and/or shrinkage. Moreover, catalytic Mo converted from lithiated MoS2 can promote the reaction kinetics and suppress heterointerface passivation by forming a building-in-electric field, thereby enhancing the reversible conversion of Sn to SnS2. Consequently, the SnS2/MoS2/DGS anode with high gravimetric and high volumetric capacities achieves 200 cycles with a high initial Coulombic efficiency of >90%, as well as excellent low-temperature performance. When the commercial Li(Ni0.8Co0.1Mn0.1)O2 (NCM811) cathode is paired with the prelithiated SnS2/MoS2/DGS anode, the full cells deliver high gravimetric and volumetric energy densities of 577Wh kg-1 and 853Wh L-1, respectively. This work highlights the significance of integrating spatial confinement and atomic heterointerface engineering to solve the shortcomings of conversion-/alloying typed TMS-based anodes to construct outstanding high-energy LIBs.

Construction of electron-interactive CoMoO4 @ CoP core–shell structure on boron-doped graphene aerogel as strongly interface coupled hybrid electrodes for high flexible supercapacitor

Exploring high energy density, lightweight and self-supporting flexible electrodes is essentially significant to flexible energy storage equipment. Herein, boron-doped three-dimensional porous graphene aerogel (BGA) is engineered and novel flake-like CoP encapsulating flower-like CoMoO4 core–shell structure is arranged on it (CoMoO4@CoP/BGA) utilizing a combination of solvothermal, freeze-drying and vapor deposition techniques. Boron-doped graphene aerogel as flexible self-supporting positrode creates a unique three-dimensional porous interface with a larger specific surface area, which is conducive to exposing more active sites and avoids the additional process of adding binders and conductive agents. The heterointerface engineering of CoP epitaxial growth on CoMoO4 can efficiently enhance electrolyte ions adsorption ability and fast reaction kinetics. As expected, the fabricated CoMoO4@CoP/BGA demonstrates a better specific capacitance of 3056.4F/g than that of CoMoO4/BGA (1582.4F/g) and pure CoMoO4 (669.2F/g), apart from retains the remarkable cyclic stability of 88.4 % after 10,000 cycles. Furthermore, a hybrid supercapacitor composed of CoMoO4@CoP/BGA and BGA can provide a high energy density of 50.2 Wh kg−1 at 800.0 W kg−1, and retains good capacitance retention of 95.6 % after 10,000 cycles, which can be attributed to the large specific surface of B doping 3D porous graphene aerogel and the rich strong coupling interface synergy between CoP and CoMoO4. More importantly, this work provides important guidance for the design of heterojunction electrodes based on heteroatom doped graphene aerogel and phosphides @ oxide based flexible energy storage devices.

Emergence of Optical Anisotropy in Moiré Superlattice via Heterointerface Engineering.

The interaction between light and moiré superlattices presents a platform for exploring unique light-matter phenomena. Tailoring these optical properties holds immense potential for advancing the utilization of moiré superlattices in photonics, optoelectronics, and valleytronics. However, the control of the optical polarization state in moiré superlattices, particularly in the presence of moiré effects, remains elusive. Here, we unveil the emergence of optical anisotropy in moiré superlattices by constructing twisted WSe2/WSe2/SiP heterostructures. We report a linear polarization degree of ∼70% for moiré excitons, attributed to the spatially nonuniform charge distribution, corroborated by first-principles calculations. Furthermore, we demonstrate the modulation of this linear polarization state via the application of a magnetic field, resulting in polarization angle rotation and a magnetic-field-dependent linear polarization degree, influenced by valley coherence and moiré potential effects. Our findings demonstrate an efficient strategy for tuning the optical polarization state of moiré superlattices using heterointerface engineering.

Enhancement of urea oxidation reaction in alkaline condition via heterointerface engineering

Water electrolysis involving low energy barrier anodic urea oxidation reaction (UOR) is a promising way for hydrogen production. In this study, we present a superior heterostructured UOR electrocatalyst of (NiFeCo)Sx/FeOOH/NiFeCo(OH)x supported on conductive Ni foam prepared using a simple, ultrafast, energy-saving single-step corrosion engineering method. Leveraging the high conductivity of the (NiFeCo)Sx, plentiful Fe3+ in the amorphous FeOOH, high catalytic activity of the NiFeCo(OH)x, and abundant heterointerfaces, the resulting (NiFeCo)Sx/FeOOH/NiFeCo(OH)x electrode exhibits remarkable electrocatalytic performance toward UOR under alkaline condition. The electrocatalyst shows an ultra-low potential of 1.36 V at 100 mA cm−2, a small Tafel slope of 24.8 mV dec–1, and excellent stability. Density functional theory calculation shows that the multiple heterointerfaces provide synergistic effect of shifting the d-band center to optimize the intermediate chemisorption energy, thus boosting the catalytic kinetics for catalyzing UOR.

Carbon nanofiber aerogel microspheres with heterogeneous skin-core structure for broadband electromagnetic wave absorption

The advancement in the miniaturization of carbon aerogels into micro-sized spheres represents a significant development in the creation of ultralight, broadband microwave absorbers. Notwithstanding this innovation, there is still a considerable challenge in optimizing microwave absorption (MA) performance through heterointerface engineering within aerogel microspheres. Herein, we have developed skin-core heterogeneous aerogel microspheres by the in situ generation of ZIF-67 nanocrystals on the wet-spun aramid nanofiber (ANF) aerogel microspheres, followed by a high-temperature carbonization process. The resulting Co@C nanoparticle-enshrouded ANF-derived carbon nanofiber aerogel microspheres (Co@C/CNFAMs) demonstrate an exceptional equilibrium between impedance matching and multi-faceted attenuation. Remarkably, the Co@C/CNFAM2 sample attains a maximum effective absorption bandwidth of 8.72 GHz, while maintaining an ultralow filler proportion of 1.5 wt%. Moreover, the Co@C/CNFAM3 sample achieves a minimum reflection loss of −72.34 dB with a filling ratio of 1.2 wt%. Our findings offer a refined approach to the intricate engineering of heterostructures, along with the strategic macrostructural design, paving the way for the development of aerogel-based microwave absorbers that represent the next step in material science innovation.

Built‐In Electric Field Enhancement Strategy Induced by Cross‐Dimensional Nano‐Heterointerface Design for Electromagnetic Wave Absorption

AbstractNano‐heterointerface engineering has been demonstrated to influence interfacial polarization by expanding the interface surface area and constructing a built‐in electric field (BEF), thus regulating electromagnetic (EM) wave absorption. However, the dielectric‐responsive mechanism of the BEF needs further exploration to enhance the comprehensive understanding of interfacial polarization, particularly in terms of quantifying and optimizing the BEF strength. Herein, a “1D expanded 2D structure” carbon matrix is designed, and semiconductor ZnIn2S4 (ZIS) is introduced to construct a carbon/ZIS heterostructure. The cross‐dimensional nano‐heterointerface design increases interface coupling sites by expanding the interface surface area and induces an increase in the Fermi level difference on both sides of the interface to modulate the distribution of interface charges, thereby strengthening the BEF at the interface. The synergistic effect leads to excellent EM absorption performance (minimum reflection coefficient RCmin = −67.4 dB, effective absorption bandwidth EAB = 6.0 GHz) of carbon/ZIS heterostructure. This work introduces a general modification model for enhancing interfacial polarization and inspires the development of new strategies for EM functional materials with unique electronic behaviors through heterointerface engineering.

Synergistic effect and heterointerface engineering of cobalt/carbon nanotubes enhancing electromagnetic wave absorbing properties of silicon carbide fibers

Synergistic effect and heterointerface engineering of cobalt/carbon nanotubes enhancing electromagnetic wave absorbing properties of silicon carbide fibers

Heterostructure Interface Construction of Cobalt/Molybdenum Selenides toward Ultra‐Stable Sodium‐Ion Half/Full Batteries

AbstractTransition metal selenides (TMSes) are considered promising candidates for the anodes of sodium‐ion batteries (SIBs) due to their substantial theoretical capacity. However, TMSes still face with inferior cycling lifespan caused by sluggish Na+ diffusion kinetics and vigorous volume variations during dis/charge processes. Engineering heterostructure is an attractive solution for rapid Na+ transfer, and introducing carbonaceous materials also facilitates enhanced conductivity and structural stability. Herein, CoSe/MoSe2 heterostructure combined with homogeneous carbon composites are rational designed. The kinetic analysis and theoretical calculations verified that heterointerface engineering induced build‐in electric field effect can amplifies the Na+ diffusion kinetics, while carbon contributes to enhanced electrical conductivity and structural stability. Expectedly, the CoSe/MoSe2‐C exhibits high capacity and extremely ultra‐long lifespan (320.9 mAh g−1 at 2.0 A g−1 over 10,000 cycles with an average decay of only 0.01781 mAh g−1 per cycle). Furthermore, in situ X‐ray diffraction (XRD), ex situ X‐ray photoelectorn (XPS), and high‐resolution electron microscopy (HRTEM) are exploited to explore the Na+ storage mechanism. In addition, the Na3V2(PO4)3@rGO//CoSe/MoSe2‐C (NVP@rGO//CoSe/MoSe2‐C) pouch‐type full‐cells are successfully assembled and delivered satisfactory performance. This research presents a viable strategy for the targeted engineering of TMSes aimed at enhancing the efficiency of SIBs.

Improved hydrogen generation integrated with methanol electrooxidation by manganese selenide/cobalt selenide heterostructure electrocatalyst

The electro-oxidation of mono-alcohol molecules to produce valuable products in combination with the formation of hydrogen is not an easy process. Herein, the manganese selenide/cobalt selenide hetero-nanoparticles embedded in nitrogen-doped carbon (namely MnSe/Co0.85Se@NC) are fabricated as high-performance catalysts by regulating electronic structures through heterointerface engineering. Experimental and theoretical results demonstrate that the formation of MnSe/Co0.85Se heterostructure will take charges from the Co0.85Se sites, which is advantageous to the adsorption of mono-alcohol molecules and thus makes Co0.85Se a high-performance electrocatalyst for mono-alcohol oxidation reactions (M−AOR). Notably, the activity order of M−AOR on the MnSe/Co0.85Se@NC electrode is methanol > ethanol > n-propanol > isopropanol. Furthermore, the charge transfer from Co0.85Se to MnSe occurs, resulting in a strong electronic interaction at the heterointerface of MnSe/Co0.85Se, giving it superior HER activity. Impressively, MnSe/Co0.85Se@NC can be used as a bifunctional catalyst for methanol-assisted water electrolysis in a two-electrode configuration, which only demands a cell potential of 1.49 V to obtain the 10 mA cm−2 current density, accompanying with valuable formate generation at the anode and hydrogen generation at the cathode. This tactic employing a heterogeneous electrocatalyst to produce high-value chemicals is considered of great importance in the development of new energy technology.

Customized heterostructure of transition metal carbides as high-efficiency and anti-corrosion electromagnetic absorbers

The ever-increasing presence of electronic devices and communication equipment imposes a critical demand for the development of highly efficient microwave absorption materials, as a means to combat the detrimental effects of electromagnetic (EM) wave pollution. The extraordinary advantages offered by heterointerface and defect engineering, coupled with their distinctive electromagnetic traits, infuse boundless energy into the development of MXene-based absorbers for EM attenuation. However, there is still a lack of understanding regarding the consequences of irreversible oxidation on the surface chemistry and dielectric properties of MXenes. Through the employment of heterointerface engineering strategy to promote interfacial charge accumulation and polarization, remarkable EM absorption properties coupled with corrosion resistance have been realized. The partially oxidized MXenes, particularly Ti3C2Tx and V2CTx, displayed remarkable reflection loss (RL) values of −56.83 dB and −52.13 dB, respectively. Additionally, the Nb2CTx composites showcased exceptional performance, offering a significantly broader bandwidth of 9.84 GHz. By conducting an extensive examination of the structural changes in MXenes, this work aims to elucidate the oxidation mechanisms and proposes a feasible method for producing MXenes with excellent absorption properties.

Ultrafast and Parts-per-Billion-Level MEMS Gas Sensors by Hetero-Interface Engineering of 2D/2D Cu-TCPP@ZnIn2S4 with Enriched Surface Sulfur Vacancies.

The primary challenge for resonant-gravimetric gas sensors is the synchronous improvement of the sensitivity and response time, which is restricted by low adsorption capacity and slow mass transfer in the sensing process and remains a great challenge. In this study, a novel 2D/2D Cu-TCPP@ZnIn2S4 composite is successfully constructed, in which Cu-TCPP MOF is used as a core substrate for the growth of 2D ultrathin ZnIn2S4 nanosheets with well-defined {0001} crystalline facets. The Cu-TCPP@ZnIn2S4 sensor exhibited high sensitivity (1.5 Hz@50 and 2.3 Hz@100 ppb), limit of detection (LOD: 50 ppb), and ultrafast (9 s @500 ppb) detection of triethylamine (TEA), which is the lowest LOD and the fastest sensor among the reported TEA sensors at room temperature, tackling the bottleneck for the ultrafast detection of the resonant-gravimetric sensor. These above results provide an innovative and easily achievable pathway for the synthesis of heterogeneous structure sensing materials.