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The development of two-dimensional materials is currently rapid due to their outstanding electronic and optical properties, and research on them has never ceased. Our study explored the geometric and electro-optical characteristics of a novel BAs/ZnSe heterostructure through first-principles calculations. We also researched the effects of P atom doping and the stacking of rotated monolayers on the functioning of the BAs/ZnSe heterostructure. Findings from our analysis suggest that the BAs/ZnSe heterostructure embodies a type-II heterojunction, and its band gap is 0.38 eV. This configuration facilitates the efficient division of photoexcited electron–hole pairs at the heterointerface. When the layer spacing reaches 3.3 Å, the binding energy is the lowest and the heterojunction is the most stable. The introduction of an electric field and mechanical stress will lead to the modification of the heterostructure's band gap, ultimately reducing it to zero, thereby exhibiting metallic properties. It is noteworthy that when using an electric field range of −0.9 < Eext < −0.7 eV Å−1, the BAs/ZnSe heterostructure transfers from a type-II heterojunction to a type-I heterojunction, and becomes a direct band gap. A similar transition also occurs when the applied stress range is 3% < ε < 6%, and there's a type-I to type-II transition. In particular, compared to the individual monolayers, the BAs/ZnSe heterostructure exhibits enhanced optical absorption coefficients, notably in the ultraviolet absorption spectrum, exhibiting an expanded range of absorption. The light absorption capability will also vary with different electric fields and strains. This suggests that the BAs/ZnSe heterostructure can shine in a wider range of applications. [ABSTRACT FROM AUTHOR]

A new type of hybrid material (NCMTs@MoO2/FeNi3) with a multi-layer heterostructure was designed and fabricated via a one-step pyrolysis process using FeOOH/NiMoO4@PDA as the precursor. FeOOH/NiMoO4@PDA was prepared by the solvothermal method, followed by the nickel-ion etching method coupled with the polymerization of dopamine (DA). The as-obtained material was made of nitrogen-doped carbon nanotubes embedded with FeNi3 and MoO2 nanoparticles (NPs). Notably, the FeNi3 NPs exhibited significantly improved performance in the reduction of 4-nitrophenol (4-NP) and adsorption of histidine-rich protein as well as provided appropriate magnetism resources. The MoO2 NPs imparted a metallic nature with excellent conductivity, and the N-doped mesoporous carbon microtubes also improved conductivity and facilitated mass transfer, thus leading to enhanced performance in catalysis. Benefiting from the 1D hierarchical porous structure and compositional features, the NCMTs@MoO2/FeNi3 composites exhibited excellent performance in 4-NP reduction and protein adsorption via specific metal affinity between the polyhistidine groups of proteins and the FeNi3 NPs. The result presented here indicates that the strategy of combining tailored components, heterostructuring, and carbon integration is a promising way to obtain high-performance composites for other energy-related applications. [ABSTRACT FROM AUTHOR]

Organic–inorganic hybrid perovskites have been intensively studied in past decades due to their outstanding performance in solar cells and other optoelectronic devices. Recently, the emergence of two-dimensional/three-dimensional (2D/3D) heterojunctions have enabled many solar cell devices with >25% power conversion efficiency, driven by advances in our understanding of the structural and photophysical properties of the heterojunctions and our ability to control these properties through organic cation configuration in 2D perovskites. In this feature article, we discuss a fundamental understanding of structural characteristics and the carrier dynamics in the 2D/3D heterojunctions and their impact factors. We further elaborate the design strategies for the molecular configuration of organic cations to achieve thorough management of these properties. Finally, recent advances in 2D/3D heterostructures in solar cells, light-emitting devices and photodetectors are highlighted, which translate fundamental understandings to device applications and also reveal the remaining challenges in ligand design for the next generation of stable devices. Future development prospects and related challenges are also provided, with wide perspectives and insightful thoughts. [ABSTRACT FROM AUTHOR]

Photocatalytic ammonia production holds immense promise as an environmentally sustainable approach to nitrogen fixation. In this study, In2O3/In2S3-ZnCdS ternary heterostructures were successfully constructed through an innovative in situ anion exchange process, coupled with a low-temperature hydrothermal method for ZnCdS (ZCS) incorporation. The resulting In2O3/In2S3-ZCS photocatalyst was proved to be highly efficient in converting N2 to NH3 under mild conditions, eliminating the need for sacrificial agents or precious metal catalysts. Notably, the NH4+ yield of In2O3/In2S3-0.5ZCS reached a significant level of 71.2 μmol g−1 h−1, which was 10.47 times higher than that of In2O3 (6.8 μmol g−1 h−1) and 3.22 times higher than that of In2O3/In2S3 (22.1 μmol g−1 h−1). This outstanding performance can be attributed to the ternary heterojunction configuration, which significantly extends the lifetime of photogenerated carriers and enhances the spatial separation of electrons and holes. The synergistic interplay between CdZnS, In2S3, and In2O3 in the heterojunction facilitates electron transport, thereby boosting the rate of the photocatalytic nitrogen fixation reaction. Our study not only validates the efficacy of ternary heterojunctions in photocatalytic nitrogen fixation but also offers valuable insights for the design and construction of such catalysts for future applications. [ABSTRACT FROM AUTHOR]

Metal sulfides are receiving increasing interest for lithium-ion batteries owing to their good reaction reversibility and high reversible theoretical capacity. However, their development still stays at the infancy stage due to the low conductivity and the volume change during charging and discharging processes, resulting in poor rate performance and cycling stability. Herein, a bimetallic sulfide heterostructured SnS/CoS embedded in reduced graphene oxide substrate (SnS/CoS@rGO) is designed by an ingenious design of a one-step method. The rich interphase boundaries in SnS/CoS heterostructures can significantly improve ionic and electronic diffusion kinetics because of the built-in electric field. In addition, the three-dimensional rGO substrate provides extra efficient transfer paths for electrons and ions, and can buffer volume changes to maintain outstanding structural stability. As a result, the SnS/CoS@rGO electrode exhibits high reversible capacity of 1223 mAh g−1 after 400 cycles at a current density of 500 mA g−1. Even at a current density of 1 A g−1, the capacity remains at 846 mAh g−1 after 400 cycles. [ABSTRACT FROM AUTHOR]

Two-dimensional transition metal dichalcogenide heterostructures are potential candidates for next-generation semiconductor materials due to their extremely thin atomic structure and better optoelectronic properties. As a common method for growing heterostructures, chemical vapor deposition (CVD) can synthesize both lateral and vertical heterostructures. However, the controlled synthesis of heterostructures still faces challenges due to fewer studies about the evolution of heterostructure morphology under different conditions. In this study, heterostructures with sharp interfaces are fabricated via the vapor–liquid–solid (VLS) growth-based CVD technique using mixed sodium molybdate and sodium tungstate solutions. By optimizing a series of growth parameters, the modulation of MoxW1−xS2/MoS2 heterostructure morphology is achieved. In addition, lateral and vertical MoxW1−xS2/MoS2 heterostructures are synthesized by changing the molybdenum–tungsten molar ratio. This study provides a new strategy for synthesizing heterostructures with different growth ways. [ABSTRACT FROM AUTHOR]

The development of sensors with excellent and low detection limits is critical for detecting trimethylamine (TMA) in seafood safety monitoring and healthcare. Herein, WO3 flower-like structures functionalized with NiWO4 were fabricated using a combination of solvothermal and hydrothermal methods and subsequently utilized in gas sensors for TMA detection. The gas-sensing results demonstrated that the incorporation of NiWO4 nanoparticles onto the WO3 surface reduced the optimal operating temperature and further enhanced the selectivity and response to TMA. Representatively, the 10-NiWO4/WO3 sensor exhibited a sensing response of 12.05 to 10 ppm TMA, along with rapid response/recovery times (14/17 s), a low theoretical detection limit of 14.26 ppb, a wide detection range, and excellent long-term stability at 150 °C. These improved capabilities are primarily ascribed to the modulation of surface carrier concentration within the n–n heterojunction at the NiWO4/WO3 interface, coupled with the catalytic promotion effect of NiWO4 on gas-sensing reactions, and the unique hierarchical flower-like structures. This study highlights the considerable potential of 3D flower-like NiWO4/WO3 heterostructures as a highly promising sensing material for TMA gas sensors. [ABSTRACT FROM AUTHOR]

The construction of heterostructures in nanostructured anodes has been testified to be a feasible strategy to promote the comprehensive sodium storage properties of sodium-ion batteries, which benefit from the unique synergistic effects and interfacial interactions between different constituents. However, it remains a big challenge to develop simple and cost-effective synthesis methods for rationally building heterostructures within electrode materials. In this study, a facile and cost-effective approach using a hydrothermal method and a subsequent annealing process has been developed to engineer flower-like MoO2/MoS2 heterostructures encapsulated in nitrogen-doped carbon (MoO2/MoS2@NC) as anodes for sodium-ion batteries. The nitrogen-doped carbon enhances the electrical conductivity and mitigates the huge volume expansion of the electrode materials during the sodiation/desodiation process via the confinement effect. The heterostructure endows the MoO2/MoS2@NC anode with rapid Na+ diffusion and charge transfer within the electrode, contributing to a fast electrochemical reaction kinetics. Benefiting from the good synergistic effects of different components and unique merits of the heterostructures, the MoO2/MoS2@NC anode exhibits favorable sodium storage properties, including high capacity and good rate properties as well as excellent cycling stability. [ABSTRACT FROM AUTHOR]

We develop a new type of heterostructure nanocomposite made of reduced graphene oxide-boron carbon nitride nanosheets (rGOBCN) by B–C covalent bonds. The rGO-BCN nanocomposite delivers a large specific surface and excellent electrochemical properties, and is then constructed into flexible fabric-based high-performance supercapacitor electrodes based on the microfluidic electrospinning technology. [ABSTRACT FROM AUTHOR]

A one dimensional (1D) hierarchical structure with hybrid components is extremely attractive for catalytic application considering the integrated properties and synergistic effect of its individual components. In this work, an effective approach combined with a hydrothermal reaction, water bath deposition, and postcalcination treatment is developed to decorate NiCo2O4 nanoparticles (NPs) on MnO2 nanowires (NWs), leading to the formation of 1D hierarchical heterostructures as efficient oxidase mimics for the detection of glutathione. The oxidase catalytic activity of the as-prepared MnO2@NiCo2O4 composites is much higher than that of individual NiCo2O4 NPs and MnO2 NWs because of the synergistic effect between the two components. Owing to the superior catalytic efficiency of the prepared MnO2@NiCo2O4 nanowires, a colorimetric route for the rapid and accurate detection of glutathione has been developed. This shows that the 1D hierarchical MnO2@NiCo2O4 composites as catalytic materials potentially have a good application prospect. [ABSTRACT FROM AUTHOR]

Recently, the combination of two different two-dimensional (2D) semiconductors to generate van der Waals (vdW) heterostructures has emerged as an effective strategy to tailor their physical properties, paving the way for the development of next-generation devices with improved performance and functionality. In this work, we designed an MoS2/MoGe2N4 heterostructure and explored its electronic structures, optical properties and contact characteristics using first-principles calculations. The MoS2/MoGe2N4 heterostructure is predicted to be energetically, thermally and dynamically stable, indicating its feasibility for experimental synthesis in the future. The MoS2/MoGe2N4 heterostructure forms type-I band alignment, suggesting that it can be considered as a promising material for optoelectronic devices, such as light-emitting diodes, and in laser applications. Furthermore, the type-I MoS2/MoGe2N4 heterostructure has enhanced optical absorption in both the visible and ultraviolet regions. More interestingly, the electronic properties and contact characteristics of the MoS2/MoGe2N4 heterostructure can be tailored by applying in-plane biaxial strain. Under the application of compressive and tensile strains, transformations between type-I and type-II band alignments and between semiconductor and metal can be achieved in the MoS2/MoGe2N4 heterostructure. Our findings could provide useful guidance for experimental synthesis of materials based on the MoS2/MoGe2N4 heterostructure for electronic and optoelectronic applications. [ABSTRACT FROM AUTHOR]

The presence of antibiotics in aquatic systems poses a significant risk to both the ecological balance and human health. To address this issue, the development of advanced photocatalytic materials capable of efficiently treating antibiotic-contaminated wastewater is imperative. In this investigation, we successfully synthesized nitrogen–phosphorus co-doped carbon dots (NPCDs) modified (001) TiO2/Ti3C2Tx composites via a series of uncomplicated hydrothermal reactions, ensuring visible light responsivity. Comprehensive characterization of the composite photocatalysts was conducted using XRD, FT-IR, N2 adsorption, SEM, TEM, XPS, UV-Vis DRS, and PL techniques. Subsequently, the photocatalytic performance was assessed through the degradation of tetracycline hydrochloride (TC) and ceftiofur sodium solutions under visible light irradiation. The optimized composites exhibited remarkable photocatalytic degradation efficiencies of 93.4% and 75.5% for TC and ceftiofur sodium, respectively, under visible light, following quasi-primary kinetic behavior. Reactive free radical capture experiments highlighted the predominant roles of ˙O2− and ˙OH species in the photocatalytic degradation process. Additionally, we proposed plausible mechanisms governing photocatalytic degradation based on the obtained results. The heightened photocatalytic reactivity arises from the efficient transfer of photogenerated electrons through the NPCDs → TiO2 →Ti3C2Tx pathway, a mechanism that effectively facilitates the separation and transfer of photogenerated charge carriers. [ABSTRACT FROM AUTHOR]

Herein, we developed a cascade growth strategy to fabricate laminated heterostructures based on graphdiyne (GDY), which can not only retain the intrinsic structure of GDY to the maximum extent, but can also realize the effective regulation of its basic properties. A chlorine heteroatom-doped GDY film (Cl-GDY/GDY) was prepared by coupling hexaalkynylbenzene with a copper substrate pre-decorated with chlorine-substituted GDY (Cl-GDY). An interweaved aggregating morphology consisting of nanofibers and nanosheets was observed, which can be assigned to Cl-GDY and GDY components, respectively. Moreover, the interaction between Cl-GDY and GDY induced a tunable energy level structure. As a result, the conductive properties of the Cl-GDY/GDY films were enhanced by an order of magnitude rather than the simple superposition of the two components, which was clearly observed in both a carbon/electrolyte electrochemical cell and the carbon-based heterojunction device. [ABSTRACT FROM AUTHOR]

Spatially-ordered 1D nanocrystal-based semiconductor nanostructures possess distinct merits for photocatalytic reaction, including large surface area, fast carrier separation, and enhanced light scattering and absorption. Nevertheless, establishing a valid photo-carrier transmission channel is still crucial yet challenging for semiconductor heterostructures to realize efficient photocatalysis. In this work, spatially ordered NiOOH-ZnS/CdS heterostructures were constructed by sequential ZnS coating and NiOOH photo-deposition on multi-armed CdS, which consists of {112¯0}-faceted wurtzite nanorods grown epitaxially on {111}-faceted zinc blende core. Intriguingly, the surface photovoltage spectroscopy and PbO2 photo-deposition results suggest that the photogenerated holes of CdS were first transferred to the Zn-vacancy level of ZnS and then to NiOOH, as driven by the built-in electric field between ZnS and CdS and the hole-extracting effect of the NiOOH cocatalyst, leading to the efficient charge separation of NiOOH-ZnS/CdS. With visible-light (λ > 420 nm) irradiation, NiOOH-ZnS/CdS exhibited a distinguished H2-evolution rate of 152.20 mmol g−1 h−1 (apparent quantum efficiency of 40.9% at 420 nm), approximately 18 folds that of 3 wt% Pt-loaded CdS and much higher than that of ZnS/CdS and NiOOH-CdS counterparts as well as the most reported CdS-containing photocatalysts. Moreover, the cycling and long-term H2 generation tests manifested the outstanding photocatalyst stability of NiOOH-ZnS/CdS. The study results presented here may propel the controllable design of highly-active nanomaterials for solar conversion and utilization. [ABSTRACT FROM AUTHOR]

Solar-driven artificial photosynthesis by the use of photocatalysts to convert CO2 into valuable chemical fuels provided a promising route to simultaneously alleviate the energy crisis and resolve environmental issues caused by CO2. Among the many CO2 reduction products, CH3OH is very desirable, not only because of its use in the preparation of many commercial chemicals, but also it is easy to store and handle. However, the reduction to form CH3OH directly was difficult to control. In recent years, CsPbBr3 NCs have emerged as potential photocatalysts for CO2 reduction due to their unique optoelectronic properties. Herein, the heterostructure of CsPbBr3 and carboxyl-modified rGO (rGO-COOH) was designed for photocatalytic CO2 reduction. In the solid-vapor reaction mode, only CO and CH3OH were detected for all samples after 2h of photocatalytic reaction. Through the construction of CsPbBr3/rGO-COOH composites, the total yield of CO and CH3OH products was 88.296 µmol g-1 and 90.300 µmol g-1, respectively. The average electron consumption rate (Relectron) was 359.196 µmol g-1 h-1, which was higher than that of previously reported CsPbBr3-based catalysis. This study provides new insights for designing CsPbBr3 composites and opens up new possibilities to utilize CsPbBr3 NCs to obtain CH3OH in photocatalytic applications. [ABSTRACT FROM AUTHOR]

MnO2–Mn3O4 heterostructure materials are applied in aqueous magnesium ion energy storage for the first time. The heterostructure yields an exceptionally high pseudocapacitance contribution, resulting in a specific capacitance of 313.5 F g−1 at 1 A g−1, which contrasts with that of MnO2 (108.8 F g−1) and Mn3O4 (123.5 F g−1). Additionally, it shows potential for practical applications as a cathode for magnesium ion hybrid supercapacitors (MHS). [ABSTRACT FROM AUTHOR]

The need for low-carbon solar electricity production has become increasingly urgent for energy security and climate change mitigation. However, the bandgap and carrier separation critical requirements of high-efficiency solar cells are difficult to satisfy simultaneously in a single material. In this work, several van der Waals ZnIn2X4 (X = S, Se, and Te) heterostructures were designed based on density functional theory. Our results suggest that both ZnIn2S4/ZnIn2Se4 and ZnIn2Se4/ZnIn2Te4 heterostructures are direct bandgap semiconductors at the Γ point. Besides, obvious carrier spatial separations were observed in the ZnIn2S4/ZnIn2Se4 and ZnIn2Se4/ZnIn2Te4 heterostructures. Interestingly, the ZnIn2S4/ZnIn2Se4 heterostructure has a suitable bandgap of 1.43 eV with good optical absorption in the visible light range. The calculated maximum theoretical photoelectric conversion efficiency of ZnIn2S4/ZnIn2Se4 heterostructure was 32.1%, and it can be further enhanced to 32.9% under 2% tensile strain. Compared to single-layer ZnIn2X4 materials, the electron effective mass of the ZnIn2S4/ZnIn2Se4 heterostructure is relatively low, which results in high electron mobility in the heterostructure. The suitable bandgap, obvious carrier separation, high electron mobility, and excellent theoretical photoelectric conversion efficiency of the ZnIn2S4/ZnIn2Se4 heterostructure make it a promising candidate for novel 2D-based photoelectronic devices and solar cells. [ABSTRACT FROM AUTHOR]

Heterostructures of 2D materials have provided splendid insights into fundamental phenomena and are also promising for numerous applications. However, the protocols for obtaining them remain highly specific and lack scalability. Herein, the demonstrated protocol employs surfactant-assisted exfoliation and centrifugation-based size-selection of nanosheets for synthesizing heterostructures through electrostatic self-assembly. [ABSTRACT FROM AUTHOR]

ZnO–Au@ZIF-8 core–shell heterostructures were prepared by ZIF-8 encapsulation of sacrificial ZnO–Au nanorods. Because of the catalytic activity of the Au nanoparticles and the sieving effects of the ZIF-8, the ZnO–Au@ZIF-8 heterostructures showed an outstanding response of 1.8 to 5 ppb NO2, and exhibited higher selectivity, stability, anti-humidity and fast response and recovery properties. The combination of the gas-selective catalytic activity of noble metals with the MOF filter used in this work can be easily extended to synthesize other types of MOS@MOF sensors, opening a new avenue for the detection of hazardous gases. [ABSTRACT FROM AUTHOR]

As an emerging class of hybrid complexes, donor–acceptor (D–A) hybrid heterostructures, which combine the advantages of both organic and inorganic photoactive components, provide excellent platforms for the fabrication of photochromic materials with enhanced photo-responsive performances. Herein, four novel hybrid heterostructures, namely H3TPT·(PW12O40)·2NMP (1), (H1.5TPT)2·(PW12O40) (2), (H3TPT)2·(SiW12O40)·2Cl·2MeCN (3), and H3TPT·(HPMo12O40)·Cl·3NMP (4) (TPT is tri(4-pyridyl)-s-triazine, NMP is N-methylpyrrolidone), have been synthesized and characterized. Benefitting from the strong interactions (anion–π interactions) and matching electron energy levels between the donors and acceptors, some of them exhibited ultrafast photochromic behaviour even up to 1 second. Furthermore, based on experimental and theoretical calculations, the plausible PIET process and structure–activity relationship have been discussed in detail. [ABSTRACT FROM AUTHOR]

Advances in the hydrogen evolution reaction (HER) are intricately connected with addressing the current energy crisis and quest for sustainable energy sources. The necessity of catalysts that are efficient and inexpensive to perform the hydrogen evolution reaction is key to this. Following the ground-breaking discovery of graphene, metal thio/seleno phosphates (MPX3: M – transition metal, P – phosphorus and X – S/Se), two dimensional (2D) materials, exhibit excellent tunable physicochemical, electronic and optical properties, and are expected to be key to the energy industry for years to come. Taking this into account, a facile time-effective electrostatic restacking synthesis procedure has been followed to synthesize a 2D/2D heterostructure (FePS3@BCN) involving FePS3, one of the prominent MPX3 materials, with borocarbonitride (BCN), for hydrogen evolution reaction (HER). The piled up nanosheets of FePS3 and BCN are held together by an electrostatic force, and display extreme robustness under the harsh conditions of HER application. The amalgamated electrocatalyst achieved an overpotential of 187 mV at a current density of 10 mA cm−2 with a shallow Tafel slope of 41 mV dec−1, following the Volmer–Heyrovsky mechanism. The resilience of the electrocatalyst has been examined through chronoamperometric testing for long term stability, and it is stable for more than 14 hours, which shows the excellent electrocatalytic activity for hydrogen evolution reaction owing to the strategic approach to the catalyst design, the use of numerous electrochemically active sites, large surface area and a barrier-free channel for quick ion transfer. [ABSTRACT FROM AUTHOR]

NiFe-LDH/g-C3N4 (LDH/CN) heterostructures with different amounts of NiFe-LDH (LDH) were prepared by a hydrothermal method and characterized using different experimental techniques. Their photocatalytic properties were investigated using the degradation of tetracycline hydrochloride (TC) and the production of hydrogen from water splitting. Experimental results showed that the hydrogen production rate (780.5 μmol g−1 h−1) was 2.29 times that of pristine CN, and the TC removal rate (76.3%) of 1.8LDH/CN was 3.71 times that of CN. According to the detailed study of the structural, optical, and photoelectrochemical properties, a type II charge transfer mechanism was proposed to explain the improved photocatalytic performance of LDH/CN. [ABSTRACT FROM AUTHOR]

Herein, we demonstrate the rational design of 3-dimensional nickel double hydroxide nanosheets decorated with iron-cobalt phosphide on nickel oxide (Ni(OH)2@FexCo1−xPi‖NiO) heterostructures for achieving improved overall water splitting. The as-optimized Ni(OH)2@FexCo1−xPi‖NiO heterostructures exhibited an overpotential (η) of ∼133 mV and ∼173 mV at 10 mA cm−2 for the oxygen evolution reaction (OER) and the hydrogen evolution reaction (HER), respectively, in an alkaline electrolyte through a tunable electronic interaction and stabilization of the active Ni(OH)2 and FeCoPi interface. [ABSTRACT FROM AUTHOR]

The electrocatalytic NO3− reduction reaction (NO3RR) to NH3 provides a promising pathway for ambient NH3 synthesis and environmental pollution treatment. Cu and its oxides are recognized as effective NO3RR electrocatalysts due to their favorable d-orbital energy levels and superior kinetics. In this work, mixed-valence Cu-based catalysts with tunable valence states were constructed via an inorganic salt-induced MOF-derived strategy. Notably, optimized Cu–CuxO/C-0.3 featured a Cu/Cu2O heterostructure and demonstrated the lowest Cu valence state. The resulting Cu/Cu2O heterointerface facilitated electron transfer and increased the density of electrochemically active sites, leading to an enhanced faradaic efficiency of 81.4% and a remarkable yield rate of 13.38 mg h−1 cm−2 (ca. 2.39 mol h−1 gcat.−1) at −0.8 V vs. RHE. This work presents insights for designing multi-phase heterostructured NO3RR catalysts and emphasizes their potential significance in efficient ammonia production. [ABSTRACT FROM AUTHOR]

The use of photocatalysts based on semiconductor heterostructures for hydrogen evolution is a prospective tactic for converting solar energy. Herein, visible-light-responsive three-dimensional core–shell CoSe2/ZnIn2S4 heterostructures were successfully fabricated via in situ growth of ZnIn2S4 ultrathin nanosheets on spherical CoSe2. Without any noble metal co-catalysts, the as-prepared CoSe2/ZnIn2S4 composite achieved attractive photocatalytic hydrogen evolution activity under visible light illumination. Optimal CoSe2/ZnIn2S4 achieved a hydrogen evolution rate of 2199 μmol g−1 h−1, which was 7 times higher than that of pristine ZnIn2S4 and even exceeded that of ZnIn2S4 loaded with platinum. In this distinctive core–shell heterostructure, the presence of CoSe2 could considerably improve the ability to harvest light, quicken the charge transfer kinetics, and avoid the agglomeration of ZnIn2S4 nanosheets. Meanwhile, the experimental results demonstrated that the strong interaction between CoSe2 and ZnIn2S4 at the compact interface could appropriately boost the photogenerated electron–hole pair migration and relieve charge recombination, thus improving photocatalytic hydrogen evolution activity. This work has bright prospects in constructing noble-metal-free core–shell heterostructures for solar energy conversion. [ABSTRACT FROM AUTHOR]

The energy crisis, dependence on non-renewable energy resources and environmental pollution pose a great threat to the ecosystem. Consequently, the generation and utilization of hydrogen as a renewable, pollution-free, sustainable energy resource has attracted significant attention. In this case, different approaches have been explored, among which the electrochemical production of hydrogen through HER provides an efficient, green and clean approach for the mass production of H2. Besides HER, other reactions, such as OER and ORR, are core reactions involved in different electrochemical devices that are being developed to produce green energy technologies. In all these reactions, the development of low-cost materials with high electrochemical activity compared to the state-of-the-art noble metal electrocatalysts is important. Over the last few decades, different catalyst materials have been developed for HER, OER and ORR. Among them, graphene-based materials have been widely explored either as a support material or active catalyst for the above-mentioned electrochemical reactions. Specifically, the intrinsic electrochemical activity of graphene (G) is negligible, and therefore, different strategies, including heteroatom doping, composite development and development of heterojunctions, have been used to improve its electrochemical characteristics for HER/OER and ORR. However, although great advancements have been made using N-doped graphene (NG)-based heterostructures and composites as active electrocatalysts, there is still a lack of understanding of their reaction mechanism and the active sites responsible for the enhanced electrochemical performances are still under debate. Hence, considering the research interest over the past few years on NG-based electrocatalysts, herein we attempt to present a holistic summary of the recent advances made in the synthesis strategies and understanding of the role played by the interface, composite development and active sites in HER/OER and ORR over NG-based electrocatalysts. [ABSTRACT FROM AUTHOR]

The past decades have witnessed significant advancements in the growth of two-dimensional (2D) materials, offering a wide range of potential applications in the fields of electronics, optoelectronics, energy storage, sensors, catalysis, and biomedical treatments. Epitaxial heterostructures based on 2D materials, including vertical heterostructures, lateral structures, and superlattices, have emerged as novel material systems to manipulate the intrinsic properties and unlock new functionalities. Therefore, the development of controllable preparation methods for tailored epitaxial heterostructures serves as a fundamental basis for extensive property investigation and further application exploration. However, this pursuit presents formidable challenges due to the incomplete understanding of growth mechanisms and limited designable strategies. Chemical vapor deposition (CVD) is deemed as a promising and versatile platform for the controlled synthesis of 2D materials, especially with regard to achieving lattice matching, a critical factor in epitaxial growth. Consequently, CVD holds potential to overcome these hurdles. In this Feature Article, we present our recent breakthroughs in the controllable preparation of 2D epitaxial heterostructures using CVD. Our focus revolves around the processes of morphology engineering, interface engineering, size and density engineering, and striking the delicate balance between growth and etching. Using molten metals or alloys as primary catalysts, we have achieved remarkable control over the fabrication of graphene/hexagonal boron nitride (hBN) super-ordered arrays, enabled multistage etching of graphene/hBN heterostructures, and successfully realized the construction of graphene/MXene heterostructures. Furthermore, our research endeavors encompass both bottom-up and top-down fabrication methods, offering a novel perspective on the synthesis of 2D epitaxial heterostructures. The resulting products hold immense potential for enhancing the efficiency of critical reactions such as oxygen reduction, CO2 reduction, and hydrogen evolution reactions. By presenting our methodologies for obtaining 2D epitaxial heterostructures through CVD, we aspire to inspire fellow researchers in this field to devise more feasible and controllable fabrication techniques while also fostering the exploration of diverse heterostructure configurations. Together, these advancements will undoubtedly pave the way for further breakthroughs in atomic manufacturing and novel applications. [ABSTRACT FROM AUTHOR]

A self-derivation strategy using conductive substrates is used to prepare one-piece highly efficient bifunctional electrodes, where the chosen substrate acts as both an active catalyst precursor and a conductive carrier. Here, a bifunctional catalyst, porous NiS/Ni9S8/NF-2 nanorods, was synthesized by low-temperature vulcanization after an oxalic acid etching process. To reach a current density of 10 mA cm−2, NiS/Ni9S8/NF-2 requires only a tiny overpotential of 115 mV for the HER and 176 mV for the OER, and demonstrates sustained activity for 100 hours with almost any degradation. The substrate self-derived NiS/Ni9S8/NF-2 catalyst for overall water splitting requires only a small voltage of 1.52 V to deliver 10 mA cm−2 with excellent stability. Experimental results show that the heterostructured electrocatalysts impart good catalytic properties of NiS/Ni9S8/NF-2 by modulating the electronic structure and promoting the reconstruction process from sulfides to hydroxides. This work demonstrates the success of the substrate self-derivation strategy to achieve high catalytic activity and provide a new autogenous growth technique for electrode fabrication. [ABSTRACT FROM AUTHOR]

To support the global goal of carbon neutrality, numerous efforts have been devoted to the advancement of electrochemical energy conversion (EEC) and electrochemical energy storage (EES) technologies. For these technologies, transition metal dichalcogenide/carbon (TMDC/C) heterostructures have emerged as promising candidates for both electrode materials and electrocatalysts over the past decade, due to their complementary advantages. It is worth noting that interfacial properties play a crucial role in establishing the overall electrochemical characteristics of TMDC/C heterostructures. However, despite the significant scientific contribution in this area, a systematic understanding of TMDC/C heterostructures' interfacial engineering is currently lacking. This literature review aims to focus on three types of interfacial engineering, namely interfacial orientation engineering, interfacial stacking engineering, and interfacial doping engineering, of TMDC/C heterostructures for their potential applications in EES and EEC devices. To accomplish this goal, a combination of experimental and theoretical approaches was used to allow the analysis and summary of the fundamental electrochemical properties and preparation strategies of TMDC/C heterostructures. Moreover, this review highlights the design and utilization of the interfacial engineering of TMDC/C heterostructures for specific EES and EEC devices. Finally, the challenges and opportunities of using interfacial engineering of TMDC/C heterostructures in practical EES and EEC devices are outlined. We expect that this review will effectively guide readers in their understanding, design, and application of interfacial engineering of TMDC/C heterostructures. [ABSTRACT FROM AUTHOR]

Herein, carbon-coated MoSe2 decorated Mo2CTx MXene heterostructures (MoSe2/Mo2CTx@C) have been fabricated. Mo2CTx works as a dual-function electron/ion conductor, which not only provides high conductivity and mechanical strength, but also prevents the severe self-aggregation of few layered MoSe2 nanosheets. The high reversible capacities of 405 mA h g−1 at 100 mA g−1 after 150 cycles and 258 mA h g−1 at 2000 mA g−1 after 400 cycles could be achieved for a potassium-ion battery. [ABSTRACT FROM AUTHOR]

Herein, we have demonstrated a facile method for the synthesis of CeO2/Ce–Co-LDH heterostructures using zeolitic imidazolate framework-67 as the precursor. The Ce-incorporation in Co-LDH results in 4f–2p–3d orbital overlap to tune the electronic structure whereas the oxygen-deficient CeO2 controls the interface charge transfer. This results in excellent water oxidation activity to attain 500 mA cm−2 current density at 320 overpotential. [ABSTRACT FROM AUTHOR]

Vertically stacked 2D heterostructures (HSs) created via in-plane isotropic/anisotropic 2D transition-metal dichalcogenides (TMDCs) have recently attracted wide attention owing to unique interlayer coupling characteristics and possess a perspective potential in advanced photodetectors. However, the fabrication and interlayer exciton behavior of such vertical HS remain an enormous challenge. Herein, we report on the demonstration of two kinds of 2D MoS2/ReS2-based vertical HSs by altering the Re-based precursors during the one-step CVD process. The related interlayer excitons, interlayer coupling interaction, and charge separation are elucidated by Raman-photoluminescence spectroscopy and photoresponse measurement. Lastly, the possible growth mechanism of these two types of vertical HSs has been discussed on the basis of the evaporation temperature difference between Re-based precursors and Mo foil. Such a study provides a feasible and controllable strategy for the fabrication of in-plane isotropic/anisotropic TMDC HSs with different phase structures. [ABSTRACT FROM AUTHOR]

This study describes how the optimization of Cu2O/CuO heterostructures can enhance their (photo)catalytic performance. More specifically, the evaluation of catalysts with different Cu2O/CuO molar ratios was used to optimize their performance for the hydrogenation of 4-nitrophenol under both blue-LED light and dark conditions. For the first time, we analyzed the effect of blue LED irradiation on this reaction and found that when blue LEDs are used as the light source, a Cu2O/CuO ratio of 0.15 results in rate constants 7 to 3 times higher than those of catalysts with either lower (0.01) or higher (0.42) ratios. Furthermore, this photocatalyst shows good stability, >70% after 5 cycles, and excellent chemoselectivity in the selective reduction of the nitro group in the presence of other functionalities, i.e. –COOH, –CONH2 and –OH. [ABSTRACT FROM AUTHOR]

We have conducted first-principles calculations to reveal type-II vdW heterostructures WSi2N4/MoSi2N4 with high catalytic performance, focusing on the excellent optoelectronic properties of the MA2Z4 family of 2D materials. Initially, we investigated the performance of photocatalytic water splitting of MA2Z4 family monolayers, which exhibit higher carrier mobility than traditional two-dimensional materials. Moreover, we built vdW heterostructures based on the MA2Z4 family to promote carrier spatial separation and suppress electron–hole interlayer recombination. The results show that the WSi2N4/MoSi2N4 heterostructure has negative binding energy (−33.47 meV Å−2) and forms a built-in electric field with an average charge transfer of 0.03e. Interestingly, we found that strain tuning can enhance the solar-to-hydrogen efficiencies to 18.01% at 3% biaxial strain, and the heterostructure exhibits a high light absorption coefficient with a band gap of 2.007 eV. In conclusion, the WSi2N4/MoSi2N4 heterostructure with high performance in photocatalytic hydrogen production represents a new impetus for achieving carbon neutrality. [ABSTRACT FROM AUTHOR]

Supercapacitors (SCs) have been the subject of considerable interest because of their distinct advantages. The performance of SCs is directly affected by the electrode materials. Metal oxides derived from Prussian blue analogues (PBAs) are often used as electrode materials for SCs. Herein, we developed a multi-step strategy to fabricate ternary hollow metal oxide (CuO/NiO/Co3O4) heterostructures. The core–shell structured PBA (NiHCC@CuHCC) with Ni-based PBA (NiHCC) as the core and Cu-based PBA (CuHCC) as the shell was prepared by a crystal seed method. The ternary metal oxide (CuO/NiO/Co3O4) with a hollow structure was obtained by calcinating NiHCC@CuHCC. The prepared CuO/NiO/Co3O4 demonstrates an excellent specific capacitance of 262.5 F g−1 at 1 A g−1, which is 27.4% and 16.2% higher than those of CuO/Co3O4 and NiO/Co3O4, respectively. In addition, the material showed outstanding cycling stability with a capacitance retention of 107.9% after 3000 cycles. The two-electrode system constructed with CuO/NiO/Co3O4 and nitrogen-doped graphene hydrogel (NDGH) demonstrates a stable and high energy density of 27.1 W h kg−1 at a power density of 1037.5 W kg−1. The capacitance retention rate was 100.7% after 4000 cycles. The reason for the excellent electrochemical properties could be the synergistic effect of the introduced heterojunction of CuO/NiO, the hollow structure, and various metal oxides. This strategy can greatly inspire the construction of SC electrodes. [ABSTRACT FROM AUTHOR]

A versatile bifunctional fluorene-4 diethyl amino salicylaldehyde conjugate probe, L1, was fabricated for visualization and quantitative analysis of Hg2+ and GSH separately in aqueous media. Probe L1 exclusively showed rapid sensing toward Hg2+ (LOD = ∼17.35 ppb) and GSH (LOD = ∼25.83 ppb) with a significant "turn-on" fluorescence response, along with red-shifted emission maxima at 414 nm and 420 nm. Furthermore, the morphological transformation of the probe into self-assembled heterostructures occurred upon inclusion of Hg2+ or GSH owing to analyte-induced-aggregation emission. The sensing strategy was successfully implemented to recognize Hg2+ and GSH in contaminated natural water-body samples, simulated physiological media, and real biological samples, including human serum specimens. The visual and quantitative detection of Hg2+ and GSH using affordable test strips may offer great potential for rapid preliminary environmental monitoring. [ABSTRACT FROM AUTHOR]

A series of seaweed-like heterogeneous Co3(PO4)2/Ni3(PO4)2/MOF-74-x electrocatalysts were synthesized via a hydrothermal method. The optimal composite exhibits excellent catalytic performance toward methanol/ethanol oxidation reactions (MOR/EOR) with peak current densities reaching 27.5 and 32.6 mA cm−2, respectively. This work heralds the advent of more efficient heterogeneous electrocatalysts for DAFCs and other energy conversion systems. [ABSTRACT FROM AUTHOR]

Transition bimetallic sulphides have emerged as important electrode materials for supercapacitors owing to their low toxicity, environmental friendliness, cost-effectiveness, multiple oxidation states, high natural abundance, flexible structure, and high theoretical specific capacitance. Herein, a porous nanosheet–nanosphere@nanosheet FeNi2-LDH@FeNi2S4 (FNLDH@FNS) core–shell heterostructure was directly prepared on nickel foam (NF) via a two-step hydrothermal method. The prepared electrode material exhibits an outstanding electrochemical performance. The specific capacity (Cs) values are 806 and 450 C g−1 at current density (Dc) values of 1 and 6 A g−1, respectively, revealing a satisfactory magnification performance. In addition, the FNLDH@FNS electrode exhibits a long cycle life with an supercapacitor (SC) retention rate of 92.3% after 5000 cycles at a Dc of 6 A g−1. The FNLDH@FNS//activated carbon (AC) asymmetric SC assembled with FNLDH@FNS (positive electrode) and activated carbon (AC, negative electrode) displays an energy density (Ed) of 36.67 Wh kg−1 and a power density (Pd) of 775.17 W kg−1. [ABSTRACT FROM AUTHOR]

Tin selenide (SnSe2) is a potential sensing material for NO2 detection owing to its large specific surface area and narrow bandgap. However, sensors based on pristine SnSe2 still suffer from the disadvantages of a low response value and long response/recovery time at room temperature. Herein, SnSe2/Ag2Se n–n heterojunctions with an accumulation layer are fabricated via a one-step hydrothermal method. The amounts of the SnSe2/Ag2Se heterojunctions are effectively controlled by adjusting the Ag source content. The optimized SnSe2/Ag2Se sensor shows a response value of 12 to 5 ppm NO2 at room temperature, which is 4 times larger than that of the pristine SnSe2. The SnSe2/Ag2Se sensor exhibits a significantly shorter response/recovery time (21/103 s) than most of the reported two-dimensional materials at room temperature. This excellent performance is attributed to the enhanced electron transfer and the increased adsorption sites. In addition, the SnSe2/Ag2Se sensor exhibits good selectivity, which makes it highly suitable for practical applications. [ABSTRACT FROM AUTHOR]

Tin selenide (SnSe2) is a potential sensing material for NO2 detection owing to its large specific surface area and narrow bandgap. However, sensors based on pristine SnSe2 still suffer from the disadvantages of a low response value and long response/recovery time at room temperature. Herein, SnSe2/Ag2Se n–n heterojunctions with an accumulation layer are fabricated via a one-step hydrothermal method. The amounts of the SnSe2/Ag2Se heterojunctions are effectively controlled by adjusting the Ag source content. The optimized SnSe2/Ag2Se sensor shows a response value of 12 to 5 ppm NO2 at room temperature, which is 4 times larger than that of the pristine SnSe2. The SnSe2/Ag2Se sensor exhibits a significantly shorter response/recovery time (21/103 s) than most of the reported two-dimensional materials at room temperature. This excellent performance is attributed to the enhanced electron transfer and the increased adsorption sites. In addition, the SnSe2/Ag2Se sensor exhibits good selectivity, which makes it highly suitable for practical applications. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) vertical heterostructures (HSs) constructed by two vertically stacked layers of binary transition metal dichalcogenides (TMDCs) had been widely researched during the past decade. However, it is still a huge challenge to achieve controllable synthesis of 2D ternary TMDC-based van der Waals (vdW) HSs, which have a significant impact on physical characteristics and device performance. In this review, we will introduce the fundamental characteristics and multifarious preparation strategies of various 2D ternary TMDC-based vdW HSs. Then, this highlight mainly introduces three fabrication strategies of 2D ternary TMDC-based vdW HSs, such as exfoliation, chemical vapor deposition (CVD), and combination method. The latest progress in vdW HS-related novel physical characteristics is summarized, including composition-dependent intralayer/interlayer excitons, stacking-order-dependent photoluminescence (PL) emission, long photocarrier lifetimes, improved electrical properties, and enhanced hydrogen evolution reaction (HER) catalytic activity. Finally, current challenges and prospects in this research field are clarified. [ABSTRACT FROM AUTHOR]

New software for the simulation and fitting of specular X-ray reflectivity (XRR) measurements has been developed. The novel software employs the recursive formalism of the dynamical theory of X-ray scattering and constitutes an extension of the Multiple Reflection Optimization package for X-ray diffraction (MROX). The software is used to determine the layer thicknesses, mass densities and roughnesses of quantum heterostructures of two sets of samples: Si/Ge bilayers with 1, 2, 3, 4 and 10 periods grown on Si buffer layers and (001) Si substrates, and a 50 period ZnO/Zn1−xMgxO layer grown on a m-ZnO substrate. For the case of the group IV elemental semiconductors, an increase in the interface roughness with an increasing number of periods is found. The evolution of the roughness with increasing layering complexity is suggested to be due to the decrease of the crystalline quality deduced via simulations of X-ray diffraction 004 2–ω scans. With respect to the superlattice grown on top of the wide bandgap II–VI semiconductor, XRR scans were performed for different azimuth directions, φ = {0°, 20°, 40°, 60°, 80°, 90°}. In perfect agreement with high-resolution transmission electron microscopy images, lower roughnesses are derived when the X-ray beam is perpendicular to the c-axis. Furthermore, in both systems, the derived thicknesses fully agree with the ones observed via imaging techniques. For the wurtzite one, the low averaged MgO content (∼10%) reduces the contrast between the binaries' refractive indices (mass densities) while a difference in the a-lattice parameter is still observed experimentally. The density of the Zn1−xMgxO compound is then determined as a linear interpolation between the binaries' densities weighted by the MgO content derived via XRD and used as input in the XRR simulations. The resulting XRR simulations agree perfectly with the experimental data. Thus, an approach combining reflectivity and diffraction presents substantial advantages over the single scattering mode. [ABSTRACT FROM AUTHOR]

Metal–organic frameworks (MOFs) have been extensively applied in supercapacitors. Unfortunately, metal active sites in MOFs are commonly blocked and saturated by organic ligands, leading to insufficient positions available for the electrochemical reaction. To address this issue, we develop a novel strategy to design and prepare a series of hollow metal sulfide/MOF heterostructures, which simultaneously alleviate the large volume expansion, avoid slow kinetics of metal sulfides and expose more electrochemically active sites of the MOF. Consequently, the optimized Co9S8/Co-BDC MOF heterostructure presents outstanding electrochemical performance with a high areal specific capacitance of 15.84 F cm−2 at 2 mA cm−2 and a capacitance retention rate of 87.5% after 5000 charge–discharge cycles. The asymmetric supercapacitors based on the heterostructure deliver a high energy density of 0.87 mW h cm−2 and a power density of 19.84 mW cm−2, as well as long cycling stability. This study provides a new strategy for the rational design and in situ synthesis of metal sulfide/MOF heterostructures for electrochemical applications. [ABSTRACT FROM AUTHOR]

Photocatalytic micromotors that convert light energy into mechanical energy have garnered increased interest due to their fast photoactivation, and potential for precise control and manipulation. This feature article provides key insights into the design of photocatalytic micromotors by using single semiconductors, and heterostructures. It also highlights the different strategies to develop efficient light-driven micromotors by minimizing electron–hole pair recombination and improving charge transfer among components. The remaining challenges and possible solutions are also discussed. [ABSTRACT FROM AUTHOR]

Lattice engineering is a powerful strategy not only to optimize electrocatalytic performances, but also to deepen the understanding of electrocatalytic mechanisms. Lattice engineering can be effectively achieved in core–shell nanocrystals owing to the lattice mismatch of heterostructures. Herein, we constructed three kinds of icosahedra consisting of Au73Pd27@Pt, Au66Pd34@Pt and Pd@Pt core–(interlayer)–shell by a seed-mediated method. The introduction of an ultrathin Pd interlayer in the Au66Pd34@Pt icosahedra enables us to separately identify the strain effect and ligand effect. The specific activities towards the EOR of these icosahedra are in the sequence Au73Pd27@Pt > Au66Pd34@Pt > Pd@Pt, indicating that both the ligand effect and strain effect caused by Au can enhance the activity of Pt towards the EOR. The in situ FTIR studies confirm that the EOR processes on these icosahedra are all dominated by the C2 pathway, and hence we ascribe the enhancements of EOR activities to the faster kinetics of the C2 pathway by producing acetate or acetaldehyde. [ABSTRACT FROM AUTHOR]

Metallic phase (1T) MoS2 has been regarded as an ideal catalytic material for the hydrogen evolution reaction (HER) due to its high active site density and favorable electrical conductivity. However, the preparation of 1T-phase MoS2 samples requires tough reaction conditions and 1T-MoS2 has poor stability under alkaline conditions. In this work, 1T-MoS2/NiS heterostructure catalysts grown in situ on carbon cloth were prepared by a simple one-step hydrothermal method. The obtained MoS2/NiS/CC combines the advantages of high active site density and a self-supporting structure, achieving stable 77% metal phase (1T) MoS2. The combination of NiS and 1T-MoS2 enhances the intrinsic activity of MoS2 while the electrical conductivity is improved. These advantages enable the 1T-MoS2/NiS/CC electrocatalyst to have a low overpotential of 89 mV (@10 mA cm−2) and a small Tafel slope of 75 mV dec−1 under alkaline conditions and provide a synthetic strategy of stable 1T-MoS2-based electrocatalysts for the HER by a heterogeneous structure. [ABSTRACT FROM AUTHOR]

Dumbbell-like silver bismuth iodide perovskite heterostructures were fabricated via the growth of heterogeneous silver using a modified emulsion method. Owing to the immiscibility between DMF and hexane, the silver bismuth iodide precursors in DMF could be dispersed as microscopic droplets in hexane under vigorous stirring. Subsequently, the addition of acetone as a demulsifier provided the driving force for crystallization to form dumbbell-shaped silver bismuth iodide perovskite heterostructures. In this synthesis, we added a high concentration of Ag precursors to DMF, which influenced the morphology changes to form a silver-metal-head dumbbell-shaped silver bismuth iodide perovskite hybrid system. However, in the dumbbell heterostructure, a large silver domain was exclusively grown on a single side of the AgBi2I7 system. Further, the as-prepared dumbbell-shaped AgBi2I7 heterostructure sample was used to fabricate a photo-sensitive device and its time-dependent photocurrent properties were analysed. The dumbbell-shaped metal-perovskite heterostructure sample exhibited a higher photocurrent magnitude of ∼21 and 70 μA for 0.1 and 0.2 V bias voltage, with a high ON–OFF ratio of 3.1 × 104 and 3.2 × 104, respectively. The improved photocurrent indicates that the transfer of photogenerated electrons was facilitated from the perovskite system to the metal head. [ABSTRACT FROM AUTHOR]

The application of photocatalysts for hydrogen production is limited by their low separation efficiency and poor utilization of photogenerated electron–hole pairs. To circumvent such disadvantages, the heterojunctions have been produced to improve the separation of charges and increase the activity of photocatalysts. To date, only a few studies have been conducted to investigate the interaction between the type of heterojunction interface and the photocatalytic hydrogen evolution performance of composites. Herein, the performance of an NH2-UiO-66@MoS2 composite as a photocatalyst for hydrogen production is evaluated. Moreover, NH2-UiO-66@MoS2 heterostructures were prepared through chemical bonding (C-NUM) and physical connection (P-NUM). The photocatalytic hydrogen evolution performance of NH2-UiO-66@0.2MoS2 (C-NUM-0.2) was 1.8 and 1.14 times greater than those of NH2-UiO-66 and P-NUM, respectively. The heterojunction prepared through chemical bonding facilitated the separation of the photogenerated carriers and improved the photocatalytic stability of the composite, demonstrating its potential as a high-performance photocatalyst for hydrogen production. [ABSTRACT FROM AUTHOR]

As a kind of semiconductor with wide band gaps, MnS has received wide attention for supercapacitors. However, its electrochemical performance is often unsatisfactory. A practical solution to the poor energy density of supercapacitors is the rational design of heterostructure electrode materials. Here, a MnS-supported NiCo-LDH (MnS/NiCo-LDH) composite electrode was prepared using a convenient two-step electrodeposition technique and its electrochemical behavior was analyzed. The NiCo-LDH material was tightly adhered to the MnS nanoparticle substrate, expanding the reaction species and decreasing the thicknesses of NiCo-LDH. As a growth basis for NiCo-LDH, rough MnS is more conducive to the compact growth of NiCo-LDH. Benefiting from the porous channels in the three-dimensional net-like nanostructure, the MnS/NiCo-LDH composite electrode exhibits a high capacitance of 2022 F g−1 at 1 A g−1 and good cycling stability (78.0% remaining over 2000 cycles). Moreover, an asymmetric supercapacitor (ASC) assembled with MnS/NiCo-LDH and activated carbon achieves an energy density of 78.67 W h kg−1 at 804.8 W kg−1, and the device still retains 94.0% of its initial capacitance after 5000 cycles. The superb electrochemical performance benefits from the synergistic effect between MnS nanoparticles and NiCo-LDH nanosheets as well as its unusual porous structure. The attained results suggest that the well-designed MnS/NiCo-LDH electrode has great potential to meet the requirements for advanced energy storage devices. [ABSTRACT FROM AUTHOR]

Heteroepitaxial growth and alloys with novel physicochemical properties are attracting great attention in the photoelectric field, and inorganic heteroepitaxial growth and inorganic alloys have been well controlled via changing experimental conditions. Meanwhile, organic heterostructures (OHSs) and organic alloys (OAs) are less studied due to strict requirements for lattice parameters. Moreover, the occurrence of organic homogeneous nucleation is another main problem to solve in OHSs and OAs. Herein, by taking advantage of the similarity between N＝N and C＝C, we present a cocrystal strategy to maintain the molecular arrangement and lattice parameters, and perfect lattice matching is realized in the case of mutual substitution of N＝N and C＝C in molecules. Furthermore, we successfully achieved perfect organic heteroepitaxy and organic alloys with the same materials. We expect the realization of more versatile OHSs and OAs by introducing N＝N and C＝C into the photoelectric field. [ABSTRACT FROM AUTHOR]