Nanosheet Heterostructure Research Articles

Engineering of in-plane SnS2–SnO2 nanosheets heterostructures for enhanced H2S sensing

In-plane heterostructures has attracted considerable interest due to exceptional electron transport properties, high specific surface area, and abundant active sites. However, synthesis of in-plane SnS2–SnO2 heterostructures are rarely reported, and the deep investigation of the fine structure on reactivity is of great significance. Here, we propose partial in-situ oxidation strategy to construct the in-plane SnS2–SnO2 heterostructures and the surface properties, the ratio of two components can be finely tuned by precisely adjusting the treatment temperature. In particular, the SnS2–SnO2 heterostructures formed after annealing of SnS2 nanosheets at 350 °C exhibits a unique electronic structure and surface properties due to rich grain boundaries, which exhibits excellent gas sensing performance to H2S (Ra/Rg = 169.81 for 5 ppm H2S at 160 °C, fast response and recovery dynamic (41/101 s), excellent reliability (σ = 0.01) and sensing stability (φ = 0.11 %)). Notably, the in-plane heterostructures endow the material with abundant grain boundaries and effectively regulates the electronic structure of the Sn p-orbital, which facilitate the formation of active oxygen species (O−(ad)), thus contributing to the sensing performance. Our work provides a promising platform to design in-plane heterostructures for various advanced applications.

Construction of 0-dimensional silver quantum dot/MoSe2@MXene/3-dimensional porous copper foam composite electrodes with heterogeneous interfaces for synergistic electrocatalytic degradation of antibiotics

This study proposes a novel and efficient Ag quantum dots (QDs)/MoSe2@two-dimensional transition metal carbide/nitride (MXene)/copper foam (CF) composite electrode to address the challenge of electrocatalytic degradation of antibiotics in water. The electrode formed a unique electron donor–acceptor system by loading Ag QDs and heterostructured nanosheets on CF, significantly facilitating charge transfer and segregation at the interface. The catalytically active sites at the edges and defective locations of MoSe2 in conjunction with the two-dimensional MXene structure, which formed an efficient electron transfer channel, promoted the electron transfer from the interior to the surface and accelerated the hydrogen adsorption and reduction reactions. Moreover, the charge redistribution at the interface of Ag QDs and MoSe2@MXene formed interfacial dipoles, increasing the active sites on the catalyst surface and promoting the generation of cathodic atomic hydrogen (H*). Under optimal conditions, the degradation rate of tigecycline (TGC) reached as high as 90.1 % ± 2.4 % within 60 min. The anode-generated OH and HClO, along with the cathode-generated H, further promoted the degradation of TGC through co-catalysis. The degradation pathways were analyzed using density-functional theory (DFT) calculations and liquid chromatography-mass spectrometry (LC-MS) techniques. Moreover, toxicity analysis of the degradation products was carried out to ensure the safety of the treated wastewater discharge. A reflux continuous effluent reactor was also designed to achieve high degradation efficiency and low energy consumption after stable operation, laying the foundation for industrial applications. This technology provides new ideas for the design of green, efficient, stable, and low-consumption electrocatalytic reactors and contributes to a sustainable future environment.

Interfacial Electron Coupling in Au Nanoparticle/CoFe Layered Double Hydroxide Nanosheet Heterostructures as Water Oxidation Catalysts

Interfacial Electron Coupling in Au Nanoparticle/CoFe Layered Double Hydroxide Nanosheet Heterostructures as Water Oxidation Catalysts

Methanolysis of ammonia borane catalyzed by NiO–CuO heterostructured nanosheets: cooperation of visible light and oxygen vacancy

Methanolysis of ammonia borane catalyzed by NiO–CuO heterostructured nanosheets: cooperation of visible light and oxygen vacancy

Self-supported bimetallic iron-nickel sulfide nanosheets for efficient alkaline electrocatalytic oxygen evolution

The ongoing pursuit of cost-effective approaches for synthesizing transition metal sulfide heterostructure oxygen evolution electrocatalysts, with the objective of optimizing active site exposure and stabilizing spatial framework, remains a significant challenge. In this study, self-supported bimetallic iron-nickel sulfide (Fe1-xS-NiS/NF) nanosheet heterostructures were successfully fabricated in situ on nickel foam through the direct sulfurization of bimetallic carbonate precursors. The effects of sulfurization temperature and Fe content on the oxygen evolution reaction (OER) performance of the catalyst are investigated, and the best conditions are found to be 350 °C and 2 mmol, respectively. As expected, the optimized catalyst demonstrates remarkable OER performance in an alkaline solution with low overpotentials of 235 mV and 333 mV at high current densities of 50 mA cm−2 and 100 mA cm−2, respectively. Furthermore, the catalyst shows long-term stability lasting for 35 h at 60 mA cm−2 with a negligible shift in the polarization curve observed even after 2000 cyclic voltammetry cycles, while also exhibiting good structural preservation. The current study has the potential to offer valuable insights into the fabrication of electrocatalysts based on metal sulfide heterostructures.

2H-SnS2 assembled with petaloid 1T@2H-MoS2 nanosheet heterostructures for room temperature NO2 gas sensing.

In this study, we explored the gas-sensing capabilities of MoS2 petaloid nanosheets in the metallic 1T phase with the commonly investigated semiconducting 2H phase. By synthesizing SnS2 nanoparticles and MoS2 petaloid nanosheets through a hydrothermal method, we achieve notable sensing performance for NO2 gas at room temperature (27 °C). This investigation represents a novel study, and to the best of our knowledge no, prior similar investigations have been reported in the literature for 1T@2HMoS2/SnS2 heterostructures for room temperature NO2 gas sensing. The formed heterostructure between SnS2 nanoparticles and petaloid MoS2 nanosheets exhibits synergistic effects, offering highly active sites for NO2 gas adsorption, consequently enhancing sensor response. Our sensor demonstrated a remarkable sensing response (R a/R g = 7.49) towards 1 ppm of NO2, rapid response time of 54 s, baseline recovery in 345 s, good selectivity and long-term stability, underscoring its potential for practical gas-sensing applications.

Constructing Fe-Co2P/CeO2 heterostructure nanosheet arrays for attaining energy-saving hydrogen production in seawater

Constructing Fe-Co2P/CeO2 heterostructure nanosheet arrays for attaining energy-saving hydrogen production in seawater

Competition between Phonon-Assisted and Exciton Photoluminescence Modulated by Temperature in WSe2/Graphene Nanosheet Heterostructures for Flexible Optoelectronic Sensor Devices

Competition between Phonon-Assisted and Exciton Photoluminescence Modulated by Temperature in WSe₂/Graphene Nanosheet Heterostructures for Flexible Optoelectronic Sensor Devices

Retraction Note: Designing of CuS growing on Bi2WO6 nanosheet heterostructures based on a photoelectrochemical aptasensor for detecting ofloxacin.

Retraction Note: Designing of CuS growing on Bi2WO6 nanosheet heterostructures based on a photoelectrochemical aptasensor for detecting ofloxacin.

ZnO/TiO2 hetero-structured nanosheets for effectively detecting formaldehyde at room temperature

In this study, ZnO/TiO2 nanosheets were synthesized using a hydrothermal method followed by annealing. The resulting hierarchical ZnO–TiO2 heterostructures exhibited improved gas-sensing performance compared with pure ZnO. We demonstrated that tuning the ratio of Zn to Ti components in the heterostructure allowed us to adjust the sensor stability, with the best- performing sample having a Zn:Ti ratio of 2:1. A notable reduction was observed in both the sensor response and recovery times, down to 22 and 17 s, respectively, by utilizing nanosheet- structured ZnO/TiO2 heterojunctions. To gain insight into the interaction between the sensing materials and formaldehyde (HCHO) molecules, we performed first-principles calculations to examine the density of states, charge transfer, and energy of adsorption. Our approach to constructing heterogeneous structures contributes to overcoming the low desorption efficiency and slow response-recovery time of pure ZnO for gas-sensing applications.

Enhanced Li-O2 battery performance using NiS/MoS2 heterostructure by building internal electric field to promote the one-electron oxygen reduction/oxidation

Electrocatalysts with appropriate electron coupling toward LiO2 intermediates can exhibit superior oxygen reduction/evolution reaction kinetics in Li-O2 batteries (LOBs). In this work, a charge redistribution strategy has been developed by constructing NiS/MoS2 heterostructure nanosheet self-assembled hollow microspheres with an internal electric field to regulate the interaction with LiO2 and then improve the electrochemical performance of LOBs. Density functional theory calculations and physicochemical characterizations reveal that the difference of work functions between NiS and MoS2 promotes the electron redistribution in heterointerface via built-in electrical field, leading to increased electron density of interfacial Ni atom, thereby enhancing its electron coupling toward LiO2 intermediates and promoting one-electron oxygen reduction/oxidation reaction kinetics. As a result, the NiS/MoS2-based LOBs exhibit evidently higher discharge capacity and much better cycling performance than the batteries using NiS and MoS2. This work provides a reliable charge redistribution strategy induced by build-in electric field to design efficient catalysts for LOBs.

Built-in Electric Fields in Heterostructured Lamellar Membranes Enable Highly Efficient Rejection of Charged Mass.

Separation membranes with homogeneous charge channels are the mainstream to reject charged mass by forming electrical double layer (EDL). However, the EDL often compresses effective solvent transport space and weakens channel-ion interaction. Here, built-in electric fields (BIEFs) are constructed in lamellar membranes by assembling the heterostructured nanosheets, which contain alternate positively-charged nanodomains and negatively-charged nanodomains. We demonstrate that the BIEFs are perpendicular to horizontal channel and the direction switches alternately, significantly weakening the EDL effect and forces ions to repeatedly collide with channel walls. Thus, highly efficient rejection for charged mass (salts, dyes, and organic acids/bases) and ultrafast water transport are achieved. Moreover, for desalination on four-stage filtration option, salt rejection reaches 99.9 % and water permeance reaches 19.2 L m-2 h-1 bar-1. Such mass transport behavior is quite different from that in homogeneous charge channels. Furthermore, the ion transport behavior in nanochannels is elucidated by validating horizontal projectile motion model.

Efficiency and mechanistic insights of photocatalytic decomposition of tetracycline and rhodamine B utilizing Z-scheme g-C3N4/SnWO4 heterostructures under visible light irradiation

The hydrothermal approach was used in the design and construction of the SnWO4 (SW) nanoplates anchored g-C3N4 (gCN) nanosheet heterostructures. Morphology, optical characteristics, and phase identification were investigated. The heterostructure architect construction and successful interface interaction were validated by the physicochemical characteristics. The test materials were used as a photocatalyst in the presence of visible light to break down the antibiotic tetracycline (TC) and the organic Rhodamine B (RhB). The best photocatalytic degradation efficiency of TC (97%) and RhB (98%) pollutants was demonstrated by the optimized 15 mg of gCNSW-7.5 in 72 and 48 min, respectively, at higher rate constants of 0.0409 and 0.0772 min−1. The interface contact between gCN and SW, which successfully enhanced charge transfer and restricted recombination rate in the photocatalyst, is responsible for the enhanced performance of the gCNSW heterostructure photocatalyst. In addition, the gCNSW heterostructure photocatalyst demonstrated exceptional stability and reusability over the course of four successive testing cycles, highlighting its durable and dependable function. Superoxide radicals and holes were shown to be key players in the degradation of contaminants through scavenger studies. The charge transfer mechanism in the heterostructure is identified as Z-scheme mode with the help of UV–vis DRS analysis. Attributed to its unique structural features, and effective separation of charge carriers, the Z-scheme gCNSW-7.5 heterostructure photocatalyst exhibits significant promise as an exceptionally efficient catalyst for the degradation of pollutants. This positions it as a prospective material with considerable potential across various environmental applications.

Polarization‐Enhanced Narrow‐Band GeS2 2‐D SWIR Spectral Phototransistor

AbstractIntegrated computational spectrometers with gate‐tunable nano heterostructures and reconstruction algorithms are attractive for on‐chip gas‐sensing spectrometers and have enabled versatile spectrum detectors. However, they require the selective and optical filtering capabilities of wavelengths, restricting their efficient implementation in narrow‐band photodetection. In this study, a printable spectral phototransistor is developed with high dynamic detectivity (1012 Jones and 105 Hz at −3 db bandwidth) modulated by a GeS2 nanosheet heterostructure at short‐wave infrared (SWIR) regime. Using the transport mode switching of carriers in a heterostructure and the polarization‐sensitivity of the GeS2 two‐dimension (2‐D) nanosheet, this SWIR spectral phototransistor demonstrates an accurate narrow‐band selective (96.7% accuracy) spectrum detector and performed a deep‐learning analysis of an artificial neural network (ANN). Furthermore, this GeS2 2‐D based spectral phototransistor, characterized by its high in‐plane anisotropy and electrically reconfigurable properties, extends the applicability of narrow‐band photodetection with 15 nm Full Width at Half Maximum (FWHM) to the recognition of trace‐gases at the parts per billion (ppb) level.

Interface engineering of 2D/2D MoS2/In2S3 heterostructure for highly sensitive NO2 detection at room temperature gas sensor

Rapid industrial growth and technological advancements in recent decades have led to an urbanized society at the expense of the environment due to toxic gas emissions. Therefore, it is imperative to detect trace concentrations of harmful gas with reliable techniques. NO2 is essentially being targeted for detection among all other gases due to its enormous abundance and serious health risks. Recently, 2D-MoS2 with enormous adsorption sites and high chemical reactivity have been employed selectively to detect NO2 at room temperature (RT). Herein, uniform and high surface area MoS2/In2S3 nanosheets (NSs) heterostructures were synthesized by hydrothermal method. HR-TEM analysis confirmed the 2D/2D heterostructures of MoS2/In2S3 nanosheets (NSs), and the increase in surface area of MoS2 from 10 m2/g to 27.2 m2/g upon addition of In2S3, measured through BET analysis. The MoS2/In2S3 sensor demonstrated excellent sensing capability with a response of 185% towards 50 ppm of NO2 at RT (30 ℃). Additionally, the sensor exhibited stable detection for about 42 days, repeatability over 5 cycles, and a detection limit of 450 ppb towards NO2. The synergistic influence of 2D/2D heterostructure with significant active sites and surface area is responsible for the considerable improvement in sensing performance. Therefore, the MoS2/In2S3 nanocomposites demonstrate a facile approach for developing high-performance potentially hazardous gas detectors for RT applications.

Built‐in Electric Fields in Heterostructured Lamellar Membranes Enable Highly Efficient Rejection of Charged Mass

Separation membranes with homogeneous charge channels are the mainstream to reject charged mass by forming electrical double layer (EDL). However, the EDL often compresses effective solvent transport space and weakens channel‐ion interaction. Here, built‐in electric fields (BIEFs) are constructed in lamellar membranes by assembling the heterostructured nanosheets, which contain alternate positively‐charged nanodomains and negatively‐charged nanodomains. We demonstrate that the BIEFs are perpendicular to horizontal channel and the direction switches alternately, significantly weakening the EDL effect and forces ions to repeatedly collide with channel walls. Thus, highly efficient rejection for charged mass (salts, dyes, and organic acids/bases) and ultrafast water transport are achieved. Moreover, for desalination on four‐stage filtration option, salt rejection reaches 99.9% and water permeance reaches 19.2 L m‐2 h‐1 bar‐1. Such mass transport behavior is quite different from that in homogeneous charge channels. Furthermore, the ion transport behavior in nanochannels is elucidated by validating horizontal projectile motion model.

Nitrogen-doped MoO2/Cu heterojunction electrocatalyst for highly efficient alkaline hydrogen evolution reaction

Metal/metal-(hydr)oxide heterojunction has been proposed as an efficient means to enhance the kinetics of alkaline hydrogen evolution reaction (HER). However, the poor electronic conductivity of metal-(hydr)oxides hinders the transport of electrons and the inappropriate electronic structure of the constituent phases would lower the HER activity. Herein, a nitrogen-doped MoO2/Cu heterostructure nanosheets was prepared by a simple hydrothermal and subsequent annealing treatment, acting as a model catalyst for element-doped modified metals/metal-oxides composite towards alkaline HER. Experimental results revealed that the HER catalytic activity of the catalyst was effectively improved by the nitrogen doping and the hetero coupling effect. The obtained N–MoO2/Cu catalyst exhibited a low overpotential of 40 and 363 mV to drive the current densities of 10 and 1000 mA cm−2, respectively, and showed high stability in the constant-current test of 50 h at 10 mA cm−2, 100 mA cm−2 and 1000 mA cm−2. Impressively, the N–MoO2/Cu catalyst coupled with Ni–Fe LDH to assemble an alkaline electrolyzer only require a voltage of 1.49 V to achieve a current density of 10 mA cm−2, and could be actuated by wind power to continuously produce hydrogen.

Fe2NiO4/FeNiS2 heterostructure-assembled hollow microtubes with numerous intimate interfaces as advanced catalyst for Zn–Air battery

An efficient electrocatalyst based on hollow-structured microtubes assembled by Fe2NiO4/FeNiS2 hetero-structured nanosheets is developed for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER), as two-half electrochemical reactions at air cathode of the zinc–air battery. The Fe2NiO4/FeNiS2 nanosheets with strong interaction between Fe2NiO4 and FeNiS2 at the heterointerface can tailor the electronic structure towards boosting the catalytic activity. In addition, the hollow structure effectively reduces the charge/mass transfer resistance, while providing a large surface area. Therefore, the bifunctional activity of the proposed catalyst for both the ORR and OER approaches that of the Pt/C and surpasses that of the RuO2. The zinc–air battery with our material as air–cathodic material possesses a desirable power density of 144.22 mW cm−2 and superior cycling performance of over 1,500 cycles (40 min per cycle) at high current density of 2.0 mA cm−2, outperforming almost the latest reports in the literature.

3D hierarchical flowerball-like CoSe2/MnSe nanosheet arrays as a novel electrode for electrochemical sensing of hydrazine

Hydrazine (N2H4) is considered to be a highly toxic substance harmful to human body and environment, and has received much attention in the field of electrochemical detection in recent years. In this study, 3D hierarchical flowerball-like CoSe2/MnSe nanosheet arrays (CoSe2/MnSe FNSAs) were obtained using CoMn-LDH as precursor and cobalt glycerate spheres as the sacrificial template by simple hydrothermal reaction and selenization method. Bimetal selenides have more active electrochemical activity and more abundant electrochemical redox reactions. The unique hierarchical flowerball-like nanosheet array heterostructure can accelerate ionic diffusion kinetics and improve electron transfer. As a hydrazine electrochemical sensor, CoSe2/MnSe FNSAs exhibits excellent electrocatalytic performance with a wide detection range of 0.001–7.45 mM and a low detection limit of 0.4 μM. This strategy provides a new choice for the detection of environmental organic pollutants.

Construction of 0D guanine nanospheres/2D vermiculite nanosheets heterostructures in confined space towards humidity sensing and proton migrations

Heterostructures comprising zero–dimensional (0D) nanoparticles and two–dimensional (2D) nanosheets have garnered considerable interest for sensing applications. Guanine exhibits extraordinary functionality in terms of their abundant hydrogen bond donors/acceptors. In this study, the protonated amine matrix of guanine serves as augmented active sites, uniformly forming guanine nanoparticles (GN) between 2D vermiculite nanosheets (VMT) confined space. Through electrostatic interactions and cross–linking with heptanedioic acid (HA), a self–assembly heterostructure (GN/VMT–HA) was constructed, which may offer abundant transport channels for enhanced humidity sensing and proton migrations. The proton migrations of GN/VMT–HA increased from 0.585 mS/cm (11% RH) to 0.750 mS/cm (97%RH) at 25 °C. The humidity sensor based on GN/VMT–HA demonstrates excellent performance, including high sensitivity (30.20 Hz/%RH), small hysteresis (1.45% RH) and short response/recovery time (25 s/7 s). This study offers a simple green method for constructing 0D/2D nanocomposites for proton transfer and humidity–sensing applications.