A 1D/2D Helical CdS/ZnIn2S4Nano-Heterostructure

Construction of hierarchical NCMTs@MoO2/FeNi3 tubular heterostructures for enhanced performance in catalysis and protein adsorption

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.

Design and Fabrication of Biomass Derived Black Carbon Modified g-C3N4/FeIn2S4 Heterojunction as Highly Efficient Photocatalyst for Wastewater Treatment

The environmental deterioration caused by dye wastewater discharge has received considerable attention in recent decades. One of the most promising approaches to addressing the aforementioned environmental issue is the development of photocatalysts with high solar energy consumption efficiency for the treatment of dye-contaminated water. In this study, a novel low-cost π-π biomass-derived black carbon modified g-C3N4 coupled FeIn2S4 composite (i.e., FeInS/BC-CN) photocatalyst is successfully designed and fabricated that reveals significantly improved photocatalytic performance for the degradation of Eosin Yellow (EY) dye in aqueous solution. Under dark and subsequent visible light irradiation, the amount optimized composite reveals 99% removal performance for EY dye, almost three-fold compared to that of the pristine FeInS and BC-CN counterparts. Further, it is confirmed by means of the electron spin resonance spectrometry, quenching experiments, and density functional theory (DFT) calculations, that the hydroxyl radicals (•OH) and superoxide radicals (•O2 -) are the dominant oxidation species involved in the degradation process of EY dye. In addition, a systematic photocatalytic degradation route is proposed based on the resultant degradation intermediates detectedduring liquid chromatography tandem mass spectrometry (LC-MS/MS) analysis. This work provides an innovative idea for the development of advanced photocatalysts to mitigate water pollution.

Novel UV-LED-driven photocatalysis-chlorine activation for carbamazepine degradation by sulfur-doped NH2-MIL 53 (Fe) composites: Electronic modulation effect and the dual role of chlorine

Chlorine activation-inefficient and the generation of disinfection by-products (DBPs) has indeed limited the application of UV/chlorine process. In this study, the typical metal-organic frameworks (MOFs) NH2-MIL53(Fe) were successfully modified with organic ligands containing sulfur functional groups and applied to construct a novel UV-LED-driven heterogeneous chlorine activation system. The generation of intermediate energy levels and the charge redistribution effect on Fe-S bond facilitated the excitation of electrons and realized the effective separation of photohole (hvb+) and photoelectron (ecb-). The involvement of S-NH2-MIL53(Fe) improved the efficiency of UV-LED/chlorine process by 6 times. The effective activation of HOCl/OCl- by hvb+ and ecb- significantly enhanced the yield of HO· and Cl·. More importantly, HOCl/OCl- played a dual role in UV-LED/chlorine/S-NH2-MIL53(Fe) process as a precursor for the generation of free radicals and a catalyst for the enhancement of HO· yield, which could achieve efficient removal of the target pollutants at lower chlorine doses. In addition, the presence of low-valent sulfur species and ecb- accelerated the cycle of Fe(II)/Fe(III) and in-situ generation of HO· and Cl·. The known generation of DBPs in UV-LED/chlorine/S-NH2-MIL53(Fe) process decreased by 37.9% compared to UV-LED/chlorine process. Developing novel UV-LED/chlorine/S-NH2-MIL53(Fe) processes provided a reliable strategy to efficiently purify actual micro-polluted water bodies.

Activating two-dimensional semiconductors for photocatalysis: a cross-dimensional strategy

The emerging two-dimensional (2D) semiconductors substantially extend materials bases for versatile applications such as semiconductor photocatalysis demanding semiconductive matrices and large surface areas. The dimensionality, while endowing 2D semiconductors the unique properties to host photocatalytic functionality of pollutant removal and hydrogen evolution, hurdles the activation paths to form heterogenous photocatalysts where the photochemical processes are normally superior over these on the mono-compositional counterparts. In this perspective, we present a cross-dimensional strategy to employ thenD (n= 0-2) clusters or nanomaterials as activation partners to boost the photocatalytic activities of the 2D semiconductors. The formation principles of heterogenous photocatalysts are illustrated specifically for the 2D matrices, followed by selection criteria of them among the vast 2D database. The computer investigations are illustrated in the density functional theory route and machine learning benefitted from the vast samples in the 2D library. Synthetic realizations and characterizations of the 2D heterogenous systems are introduced with an emphasis on chemical methods and advanced techniques to understand materials and mechanistic studies. The perspective outlooks cross-dimensional activation strategies of the 2D materials for other applications such as CO2removal, and materials matrices in other dimensions which may inspire incoming research within these fields.

Construction of core-shell CoSe2/ZnIn2S4 heterostructures for efficient visible-light-driven photocatalytic hydrogen evolution

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.

Ideal Vacuum-Based Efficient and High-Throughput Computational Screening of Type II Heterojunctions

Heterojunctions featuring a type II band alignment play a crucial role in a wide range of devices, particularly in the realm of solar cells. However, the design of such heterojunctions with a specific type of band alignment poses a substantial challenge due to the immense number of potential combinations of bulk semiconductors and their relative orientations. In this study, we propose an efficient, high-throughput computational screening method tailored for heterojunctions. Our approach, using the ideal vacuum level as a reference energy, eliminates the need for explicit electronic structure calculations for junctions. Through this protocol, we identify 1041 type II heterojunctions out of 2692 structures constructed from 86 selected inorganic compounds with appropriate band gaps sourced from the Inorganic Crystal Structure Database. For potential application in solar cells, we assess these heterojunctions, and remarkably, 58 of them exhibit a power conversion efficiency (PCE) exceeding 15%, with 13 surpassing the 20% threshold. Test calculations with expensive interface models confirm the reliability of PCE predictions based on ideal vacuums. These predictions will be of benefit in assessing the material applicability for solar cell applications. Furthermore, the versatility of our proposed screening method extends beyond solar cells, making it a valuable theoretical design tool that can be applied to a wide range of heterojunction devices.

Surface-Controlled CdS/Ti3 C2 MXene Schottky Junction for Highly Selective and Active Photocatalytic Dehydrogenation-Reductive Amination

Photocatalytic valorization and selective transformation of biomass-derived platform compounds offer great opportunities for efficient utilization of renewable resources under mild conditions. Here, the novel three-dimensional hierarchical flower-like CdS/Ti3 C2 Schottky junction (MCdS) composed of surface-controlled CdS and pretreated Ti3 C2 MXene is created for photocatalytic dehydrogenation-reductive amination of biomass-derived amino acid production under ambient temperature with unprecedented activity and selectivity. Schottky junction efficiently promotes photoexcited charge migration and separation and inhibits photogenerated electron-hole recombination, which results in a super-high activity. Meanwhile, CdS with the reduced surface energy supplies sufficient hydrogen sources for imine reduction and induces the preferential orientation of alanine, thus contributing superior selectivity. Moreover, a wide range of hydroxyl acids are successfully converted into corresponding amino acids and even one-pot conversion of glucose to alanine is easily achieved over MCdS. This work illustrates the mechanism of crystal orientation control and heterojunction construction in controlling catalytic behavior of photocatalytic nanoreactor, providing a paradigm for construction of MXene-based heterostructure.

Self-Assembly of Mixed-Dimensional GeS1- x Sex (1D Nanowire)-(2D Plate) Van der Waals Heterostructures

The integration of dissimilar materials into heterostructures is a mainstay of modern materials science and technology. An alternative strategy of joining components with different electronic structure involves mixed-dimensional heterostructures, that is, architectures consisting of elements with different dimensionality, for example, 1D nanowires and 2D plates. Combining the two approaches can result in hybrid architectures in which both the dimensionality and composition vary between the components, potentially offering even larger contrast between their electronic structures. To date, realizing such heteromaterials mixed-dimensional heterostructures has required sequential multi-step growth processes. Here, it is shown that differences in precursor incorporation rates between vapor-liquid-solid growth of 1D nanowires and direct vapor-solid growth of 2D plates attached to the wires can be harnessed to synthesize heteromaterials mixed-dimensional heterostructures in a single-step growth process. Exposure to mixed GeS and GeSe vapors produces GeS1- x Sex van der Waals nanowires whose S:Se ratio is considerably larger than that of attached layered plates. Cathodoluminescence spectroscopy on single heterostructures confirms that the bandgap contrast between the components is determined by both composition and carrier confinement. These results demonstrate an avenue toward complex heteroarchitectures using single-step synthesis processes.

High-performance ZnIn2S4/Ni(dmgH)2 for photocatalytic hydrogen evolution: Ion exchange construction, photocorrosion mitigation, and efficiency enhancement by photochromic effect

In this work, a novel photocatalyst of ZnIn₂S₄/Ni(dmgH)₂ was designed by a simple chemical precipitation method and used to enhance hydrogen evolution under visible light irradiation. Along with vigorous discharges of hydrogen bubbles, an optimal rate of 36.3 mmol/g/h was reached under UV-Vis light for hydrogen evolution, nearly 4.9 times of the one from pure ZnIn₂S₄. The heterojunction exhibits steady hydrogen evolution capability and owns a high apparent quantum efficiency (AQE) of 20.45% under the monochromatic light at 420 nm. By coupling ZnIn₂S₄ with Ni(dmgH)₂, an extraordinary photochromic phenomenon was detected and attributed to the active Ni-S component in situ formed between the nickel and sulfur composites under light irradiation. The emerging sulfide benefits light absorption of the system and separation of photogenerated electron and hole pairs. Besides providing a promising photocatalyst for visible light hydrogen production, the present work is hoped to inspire new trends of catalytic medium designs and investigations.

New Conceptual Catalyst on Spatial High-Entropy Alloy Heterostructures for High-Performance Li-O2 Batteries

High-entropy alloys (HEAs) are attracting increased attention as an alternative to noble metals for various catalytic reactions. However, it is of great challenge and fundamental importance to develop spatial HEA heterostructures to manipulate d-band center of interfacial metal atoms and modulate electron-distribution to enhance electrocatalytic activity of HEA catalysts. Herein, an efficient strategy is demonstrated to construct unique well-designed HEAs spatial heterostructure electrocatalyst (HEA@Pt) as bifunctional cathode to accelerate oxygen reduction and evolution reaction (ORR/OER) kinetics for Li-O₂ batteries, where uniform Pt dendrites grow on PtRuFeCoNi HEA at a low angle boundary. Such atomically connected HEA spatial interfaces engender efficient electrons from HEA to Pt due to discrepancy of work functions, modulating electron distribution for fast interfacial electron transfer, and abundant active sites. Theoretical calculations reveal that electron redistribution manipulates d-band center of interfacial metal atoms, allowing appropriate adsorption energy of oxygen species to lower ORR/OER reaction barriers. Hence, Li-O₂ battery based on HEA@Pt electrocatalyst delivers a minimal polarization potential (0.37 V) and long-term cyclability (210 cycles) under a cut-off capacity of 1000 mAh g^-1 , surpassing most previously reported noble metal-based catalysts. This work provides significant insights on electron-modulation and d-band center optimization for advanced electrocatalysts.

Immobilization of ZnIn2S4 on sodium alginate foam for efficient hexavalent chromium removal

Photocatalytic technology has been extensively studied in the removal of toxic Cr(VI) from wastewater. However, common powdery photocatalysts suffer from poor recyclability and secondly pollution. Herein, the zinc indium sulfide (ZnIn₂S₄) particles were integrated onto the sodium alginate foam(SA) matrix through a facile way to obtain foam-shape catalyst. Diverse characterization techniques including X-ray diffraction(XRD), Fourier transform infrared(FT-IR), scanning electron microscope(SEM) and X-ray photoelectron spectroscopy(XPS) were employed to reveal the composite compositions, organic-inorganic interface interactions, mechanical property, and pore morphology of the foams. Results demonstrated that the ZnIn₂S₄ crystals wrapped on SA skeleton tightly and constructed a flower-like structure. As-prepared hybrid foam with lamellar structure showed great potential in Cr(VI) treatment due to the presence of macropores and highly available active sites. A maximum Cr(VI) photoreduction efficiency of 93 % were observed over the optimal sample of ZS-1 (with a ZnIn₂S₄:SA mass ratio of 1:1) under visible irradiation. When tested with mixed pollutants (Cr(VI)/dyes), the ZS-1 sample displayed an enhanced removal efficiency of 98 % for Cr(VI) and 100 % for Rhodamine B(RhB). Moreover, the composite maintained prominent photocatalytic performance and a relatively integral 3D structure scaffold after continuous six runs, revealing its superior reusability and durability.

Photo-Responded Antibacterial Therapy of Reinfection in Percutaneous Implants by Nanostructured Bio-Heterojunction

Percutaneous implants may experience infection for several times during their servicing periods. They need antibacterial activity and durability to reduce recurrent infection and cytocompatibility to reconstruct biosealing. A novel photoresponse bio-heterojunction (PCT) is developed herein. It consists of TiO₂ nanotubes loaded with CuS nanoparticles and wrapped with polydopamine (PDA) layer. In PCT, a built-in electric field directing from TiO₂ to CuS and then to PDA is formed, and with near-infrared (NIR) irradiation, it drives photoexcited electrons to transfer in opposite direction, resulting in the separation of electron-hole pairs and formation of reactive oxygen species (ROS). Simultaneously, PCT shows photothermal effect due to nonradiative relaxation of photoexcited electrons and thermal vibration of lattices. The synergic effect of photogenerated ROS and hyperthermia increases bacterial membrane permeability and leakage of cellular components, endowing PCT with outstanding antibacterial performance. More importantly, PCT has good antibacterial durability and cytocompatibility due to the inhibited leaching of CuS by PDA layer. In reinfected models, with NIR irradiation, PCT sterilizes bacteria, reduces inflammatory response and enhances re-integration of soft tissue efficiently. This work provides an outstanding bio-heterojunction for percutaneous implants in treating reinfection by NIR irradiation and rebuilding biosealing.

Surface Coordination of Pd/ZnIn2S4 toward Enhanced Photocatalytic Activity for Pyridine Denitrification

New surface coordination photocatalytic systems that are inspired by natural photosynthesis have significant potential to boost fuel denitrification. Despite this, the direct synthesis of efficient surface coordination photocatalysts remains a major challenge. Herein, it is verified that a coordination photocatalyst can be constructed by coupling Pd and CTAB-modified ZnIn₂S₄ semiconductors. The optimized Pd/ZnIn₂S₄ showed a superior degradation rate of 81% for fuel denitrification within 240 min, which was 2.25 times higher than that of ZnIn₂S₄. From the in situ FTIR and XPS spectra of 1% Pd/ZnIn₂S₄ before and after pyridine adsorption, we find that pyridine can be selectively adsorbed and form Zn⋅⋅⋅C-N or In⋅⋅⋅C-N on the surface of Pd/ZnIn₂S₄. Meanwhile, the superior electrical conductivity of Pd can be combined with ZnIn₂S₄ to promote photocatalytic denitrification. This work also explains the surface/interface coordination effect of metal/nanosheets at the molecular level, playing an important role in photocatalytic fuel denitrification.

1D/2D Hybrid Te/Graphene and Te/MoS2: Multifaceted Broadband Photonics and Green-Energy Applications

We highlight the enhanced electronic and optical functionalization in the hybrid heterojunction of one-dimensional (1D) tellurene with a two-dimensional (2D) monolayer of graphene and MoS₂ in both lateral and vertical geometries. The structural configurations of these assemblies are optimized with a comparative analysis of the energetics for different positional placements of the 1D system with respect to the hexagonal 2D substrate. The 1D/2D coupling of the electronic structure in this unique assembly enables the realization of the three different types of heterojunctions, viz. type I, type II, and Z-scheme. The interaction with 1D tellurene enables the opening of a band gap of the order of hundreds of meV in 2D graphene for both lateral and vertical geometries. With both static and time-dependent first-principles analysis, we indicate their potential applications in broadband photodetection and absorption, covering a wide range of visible to infrared (near-IR to mid-IR) spectrum from 380 to 10 000 nm. We indicate that this 1D/2D assembly also has bright prospects in green-energy harvesting.

Construction of a ZnIn2S4/Au/CdS Tandem Heterojunction for Highly Efficient CO2 Photoreduction

Photocatalytic CO₂ reduction technology is of great importance to alleviate energy crisis and environmental pollution; however, it remains a serious challenge due to the fast recombination of carriers. In this study, we report a three-dimensional structure of a ZnIn₂S₄/Au/CdS composite photocatalyst for the CO₂ reduction reaction, where Au nanoparticles (NPs) are evenly anchored on the surface of ZnIn₂S₄ by photodeposition and Au NPs are wrapped around by CdS. In ZnIn₂S₄/Au/CdS composite photocatalysts, Au NPs act as a bridge to construct a "semiconductor-metal-semiconductor" tandem electron transfer mechanism (ZnIn₂S₄ → Au → CdS) heterojunction, which greatly promotes the transfer of photogenerated electrons. It is worth noting that Au NPs, as a local surface plasmon resonance (LSPR) effect excited source to generate excited-state electrons, further improve the photoreduction CO₂ activity. Under UV-vis light irradiation, the CO yield of ZnIn₂S₄/Au/CdS can reach 63.07 μmol·g^-1·h^-1, which is higher than that of 6.37 μmol·g^-1·h^-1 for pure ZnIn₂S₄, 0.93 μmol·g^-1·h^-1 for CdS, 8.9 μmol·g^-1·h^-1 for ZnIn₂S₄/CdS, 31.04 μmol·g^-1·h^-1 for ZnIn₂S₄/Au, and 5.37 μmol·g^-1·h^-1 for CdS/Au. In addition, the ternary ZnIn₂S₄/Au/CdS composite photocatalyst has good cyclic stability. This study broadens the idea of designing photocatalysts with good carrier separation efficiency.

Nanoscale Double-Heterojunctional Electrocatalyst for Hydrogen Evolution

The active sites and charge/mass transfer properties in electrocatalysts play vital roles in kinetics and thermodynamics of electrocatalysis, and impose direct impacts on electrocatalytic performance, which cannot be achieved by a simplex structure. As a prototype, the authors propose a double-heterojunctional nanostructure of NiS₂ /Ni₃ C@C containing NiS₂ /Ni₃ C and Ni₃ C/C heterojunctions as a general model to optimize the above issues and boost electrocatalytic performance. During the thermal reorganization, the in situ reaction between NiS₂ nanoparticles and carbon induces the formation of Ni₃ C between them and constructs tightly contacted two kinds of interfaces among the three components. The TEM and XPS reveal the intimately contacted three components and the as-constructed interacted dual interfaces, further confirming the formation of a porous double-heterojunctional nanostructure. Theoretical calculations uncover that the electron density redistribution occurs at Ni₃ C/C interface by spontaneous electron transfer from defected carbon to Ni₃ C and lower ΔG_H* achieves at NiS₂ /Ni₃ C interface by the concentrated interfacial charge density, which favors the simultaneous realization of high catalytic activity and rapid charge/mass transfer. When applied for hydrogen evolution reaction (HER), the porous double-heterojunctional NiS₂ /Ni₃ C@C exhibits excellent HER activity and durability among all pH values. Profoundly, this special double-heterojunctional structure can provide a new model for high-performance electrocatalysts and beyond.

Organic-Inorganic Hybrid Flower-Shaped Microspheres Applied in Photoelectrochemical Sensing

Organic-inorganic hybrid materials are rarely applied in photoelectrochemical (PEC) sensing because of the serious charge-carrier recombination in organic conjugated polymers. In this work, a series of poly(3,4-ethylenedioxythiophene) (PEDOT)/ZnIn2S4 hybrid flower-shaped microspheres were synthesized using ionic liquids (ILs) as the supporting electrolyte for EDOT electropolymerization and as the regulating reagent for controlling ZnIn2S4 growth, respectively. It was found that the hybrid material [HOEMIM]NTf2-PEDOT/[HOEMIM]BF4-ZnIn2S4 ([HOEMIM]+: 1-hydroxyethyl-3-methylimidazolium cation; NTf2-: bis(trifluoromethanesulfonyl)amide) was the optimal one, with a smooth, transparent, and continuous polymer film covering the uniform and ordered cross-linked nanosheet arrays. The hybrid material could produce a high anodic photocurrent, which was about 78 times as high as that produced by the [HOEMIM]BF4-ZnIn2S4. The enhancement effect should be the highest among all the organic-inorganic hybrid materials reported so far. This was related to its unique micromorphology structure, p-n heterojunction, and the coexisting ILs, which restrained the charge-carrier recombination in PEDOT and enhanced PEDOT sensitization to ZnIn2S4. Then, a carcinoembryonic antigen PEC immunosensor was constructed based on the photoanodic sensing platform, and it exhibited good performance. Furthermore, the [HOEMIM]BF4-ZnIn2S4 was treated with NaClO solution to create the [HOEMIM]NTf2-PEDOT/[HOEMIM]BF4-S-ZnwInxSyOz general platform for both photoanodic and photocathodic sensing. As a proof of concept, L-cysteine and dissolved oxygen were used as models for photoanodic and photocathodic sensing, respectively. The results demonstrated that the general PEC platform was quite competent. This work opens up a window for the design of organic-inorganic hybrid PEC materials and will promote the application of such hybrid materials in PEC biosensing.

One-Step MOF-Templated Strategy to Fabrication of Ce-Doped ZnIn2 S4 Tetrakaidecahedron Hollow Nanocages as an Efficient Photocatalyst for Hydrogen Evolution

Achieving structure optimizing and component regulation simultaneously in the ZnIn₂ S₄ -based photocatalytic system is an enormous challenge in improving its hydrogen evolution performance. 3D hollow-structured photocatalysts have been intensively studied due to their obvious advantages in solar energy conversion reactions. The synthesis of 3D hollow-structured ZnIn₂ S₄ , however, is limited by the lack of suitable template or synthesis methods, thereby restricting the wide application of ZnIn₂ S₄ in the field of photocatalysis. Herein, Ce-doped ZnIn₂ S₄ photocatalysts with hollow nanocages are obtained via one-step hydrothermal method with an ordered large-pore tetrakaidecahedron cerium-based metal-organic frameworks (Ce-MOFs) as template and Ce ion source. The doping of Ce and the formation of ZnIn₂ S₄ tetrakaidecahedron hollow nanocages with ultrathin nanosheet subunits are simultaneously induced by the Ce-MOFs, making this groundbreaking work. The Ce-doped ZnIn₂ S₄ with a nonspherical 3D hollow nanostructure inherit the tetrakaidecahedron shape of the Ce-MOF templates, and the shell is composed of ultrathin nanosheet subunits. Both theoretical and experimental results indicate that the doping of Ce and the formation of hollow nanocages increase light capture and the separation of photogenerated charge carriers.

Construction of 2D-layered quantum dots/2D-nanosheets heterostructures with compact interfaces for highly efficient photocatalytic hydrogen evolution

The emergence of two dimensional (2D) nanosheets provides flexible platforms for the construction of semiconductor heterostructures for photocatalytic hydrogen evolution. However, the compact and conformal contact between the components with different dimensions remains challenge. Herein, we anchor the 2D layered black phosphorous quantum dots (BPQDs) onto the 2D ZnIn₂S₄ nanosheets with sulfur vacancies (V-ZIS). This unique interface between 2D layered QDs and 2D nanosheets ensures a sufficient contact area between the BPQDs and the V-ZIS, which is conducive to the transport and the spatial separation of photogenerated electrons and holes. A synergistic effect of sulfur vacancies and type-Ⅱ heterojunction results in an excellent photocatalytic hydrogen evolution performance of the BPQDs/V-ZIS composites. The hydrogen evolution rate by the BPQDs/V-ZIS without any noble-metal as cocatalyst is up to 5079 μmol g^-1h^-1 under visible light irradiation with an apparent quantum yield (AQY) of 12.03% at 420 nm, which is dramatically higher than most other photocatalysts reported previously.

Perylene diimide supermolecule (PDI) as a novel and highly efficient cocatalyst for photocatalytic degradation of tetracycline in water: A case study of PDI decorated graphitic carbon nitride/bismuth tungstate composite

Employing perylene diimide supermolecule (PDI) as metal-free cocatalyst, a novel PDI/g-C₃N₄/Bi₂WO₆ (PCB) photocatalyst was constructed for the effective degradation of antibiotics. Both the photocatalytic activity and photostability of g-C₃N₄/Bi₂WO₆ (gCB) were further improved after loading PDI. Under simulated sunlight illumination, the apparent rate constant of tetracycline (TC) degradation by PCB reached 2.6 times that of gCB. The photocatalytic activity of PCB still kept over 80% after 4 cycle experiments, while gCB only remained around 21%. The superior activity of PCB was ascribed to the synergism between the extended visible light absorption range through the participation of PDI cocatalyst and facilitated gCB-to-PDI photoelectron transfer. TC would finally be transformed into non-toxic ring opening products and mineralized. This work demonstrated that PDI was an excellent metal-free cocatalyst and exhibited great potential to boost the activity of photocatalysts.

Construction of perylene diimide/CuS supramolecular heterojunction for the highly efficient visible light-driven environmental remediation

Developing photocatalysts that are inexpensive and efficient in degrading pollutants are essential for environmental remediation. Herein, a novel system of perylene diimide (PDI)/CuS p-n heterojunction was synthesized by a two-step self-assembly strategy for removal of tetracycline in waste water. Results showed that PDI/CuS-10% exhibited highest photocatalytic behavior. The apparent rate constants for tetracycline (TC) degradation for the blend were 5.27 and 2.68 times higher than that of CuS or PDI, respectively. The enhancement of photocatalytic activity was mainly attributed to the π-π stacking and p-n junction, which can accelerate the separation of the photo-generated h⁺-e^- pairs. Besides, the light absorption of PDI/CuS from 800 to 200 nm was significantly enhanced and the absorption edge even reached the near-infrared region, which also played an important role in providing desired photocatalytic properties. Surprisingly, PDI/CuS could maintain high catalytic activity even after 5 cycles under simulated conditions, indicating that the composite had high potential for practical applications. Owing to high efficiency, low cost and wide application range, the PDI/CuS nanocomposites are promising candidates for environmental remediation.

Construction of In2S3@ZIF-8@ZnIn2S4 hierarchical nanoflower heterostructures to promote photocatalytic reduction activity

A ZIF-8 interface (as an electron donor–acceptor) is fabricated to achieve ultrahigh photoreduction efficiency by optimizing the hierarchical heterostructures.

Performance and mechanism in degradation of typical antibiotics and antibiotic resistance genes by magnetic resin-mediated UV-Fenton process

Incomplete removal of antibiotics and antibiotic resistance genes (ARGs) has often been reported in wastewater treatment plants. More efficient treatment processes are needed to reduce their risks to the environment. Herein, we evaluated the degradation of antibiotics and ARGs by using magnetic anion exchange resin (MAER) as UV-Fenton catalyst. Sulfamethoxazole (SMZ), ofloxacin (OFX), and amoxicillin (AMX) were selected as the target compounds. The three antibiotics were almost completely degraded (> 99%) following the MAER UV-Fenton reaction for 30 min. From the degradation mechanism study, it was found that Fe³⁺/Fe²⁺ could be cyclically transferred from the catalyst at permeable interface, and the photo-generated electrons could be effectively separated. The dominant reactive radicals for antibiotics degradation were hydroxide during the MAER UV-Fenton reaction. The degradation pathway for sulfamethoxazole was proposed. In addition, wastewater samples from a wastewater treatment plant were applied to investigate the removal efficiency of antibiotics and their ARGs by the MAER UV-Fenton system. A rapid decrease in antibiotics and ARGs level was observed with this reaction system. The results from this study suggest that the MAER-mediated UV-Fenton reaction could be applied for the effective removal of antibiotics and ARGs in wastewater.

Atomic heterojunction-induced accelerated charge transfer for boosted photocatalytic hydrogen evolution over 1D CdS nanorod/2D ZnIn2S4 nanosheet composites

Design of highly efficient heterojunctions for photocatalytic hydrogen evolution is of significant importance to address the energy shortage and environmental crisis. Nevertheless, the smart design of semiconductor-based heterojunctions at the atomic scale still remains a significant challenge hitherto. Herein, we report novel atomic CdS/ZnIn₂S₄ heterojunctions by in-situ epitaxially growing 2D ZnIn₂S₄ nanosheets onto the surface of 1D defective CdS nanorods. The strong electronic coupling between defective CdS and ZnIn₂S₄ is confirmed by transient photocurrent response measurements, •O₂^- and •OH radicals experiments, and PL results, leading to accelerated interfacial charge separation and transfer. Additionally, the elevated charge transfer and electronic coupling are further confirmed by theoretical calculations. Consequently, CdS/ZnIn₂S₄ hybrids exhibit superior photocatalytic hydrogen generation activity to pristine CdS. Our findings offer a new paradigm for designing atomic 1D/2D heterojunctions for efficient solar-driven energy conversion.

The intergrated nanostructure of bimetallic CoNi-based zeolitic imidazolate framework and carbon nanotubes as high-performance electrochemical supercapacitors

In this study, a series of one-dimensional (1D)/two-dimensional (2D) heterostructure hybrids were fabricated through the in situ growth of a Co and Ni bimetallic zeolitic imidazolate framework (CoNi-ZIF) around N-doped carbon nanotubes (N-CNTs). The hybrids were further exploited as effective supercapacitor materials. The N-CNTs were prepared by carbonizing a mixture of glucose and the melamine-cyanuric acid complex at a high temperature (900 °C) under N₂ atmosphere and applied as the template for the in situ synthesis of CoNi-ZIF nanosheets (NSs). The 1D N-CNTs in the hybrids can act as the high-way for charge transfer to boost the faradaic reactions. Changing the usage of metal precursors not only provided abundant redox reaction sites in 2D CoNi-ZIF NSs but also modulated the microstructures and chemical components of the hybrids. The integration of the features of N-CNTs and CoNi-ZIF NSs can result in a synergistic effect between N-CNTs and CoNi-ZIF NSs. Therefore, the obtained CoNi-ZIFs and N-CNTs hybrid (CoNi-ZIF@N-CNT) exhibited superior electrochemical capacitive performance. Comparison revealed that the CoNi-ZIF@N-CNT-2 hybrid, which was prepared with a 1:1 mass ratio of Co(NO₃)₂·6H₂O and Ni(NO₃)₂·6H₂O, displayed the largest specific capacitance of 1118F g^-1 at 1 A g^-1, which was higher than the capacitance of most reported metal-organic framework (MOF)-based supercapacitor electrodes. Moreover, the asymmetric supercapacitor based on the CoNi-ZIF@N-CNT-2 electrode exhibited a high energy density of 51.1 Wh kg^-1 at the power density of 860.1 W kg^-1 and good cycle stability. This work can provide a facile and effective way for the fabrication of heterostructured 1D/2D nanostructures based on 2D MOFs for advanced energy storage.

ZnIn2 S4 -Based Photocatalysts for Energy and Environmental Applications

As a fascinating visible-light-responsive photocatalyst, zinc indium sulfide (ZnIn₂ S₄ ) has attracted extensive interdisciplinary interest and is expected to become a new research hotspot in the near future, due to its nontoxicity, suitable band gap, high physicochemical stability and durability, ease of synthesis, and appealing catalytic activity. This review provides an overview on the recent advances in ZnIn₂ S₄ -based photocatalysts. First, the crystal structures and band structures of ZnIn₂ S₄ are briefly introduced. Then, various modulation strategies of ZnIn₂ S₄ are outlined for better photocatalytic performance, which includes morphology and structure engineering, vacancy engineering, doping engineering, hydrogenation engineering, and the construction of ZnIn₂ S₄ -based composites. Thereafter, the potential applications in the energy and environmental area of ZnIn₂ S₄ -based photocatalysts are summarized. Finally, some personal perspectives about the promises and prospects of this emerging material are provided.

Ternary hybrid CuO-PMA-Ag sub-1 nm nanosheet heterostructures

Multi-component two-dimensional (2D) hybrid sub-1 nm heterostructures could potentially possess many novel properties. Controlling the site-selective distribution of nanoparticles (NPs) at the edge of 2D hybrid nanomaterial substrates is desirable but it remains a great challenge. Herein, we realized for the first time the preparation of ternary hybrid CuO-phosphomolybdic acid-Ag sub-1 nm nanosheet heterostructures (CuO-PMA-Ag THSNHs), where the Ag NPs selectively distributed at the edge of 2D hybrid CuO-PMA sub-1 nm nanosheets (SNSs). And the obtained CuO-PMA-Ag THSNHs as the catalyst exhibited excellent catalytic activity in alkene epoxidation. Furthermore, molecular dynamics (MD) simulations demonstrated that the SNSs interact with Ag NPs to form stable nanoheterostructures. This work would pave the way for the synthesis and broader applications of multi-component 2D hybrid sub-1 nm heterostructures.

Deposition of zinc cobaltite nanoparticles onto bismuth vanadate for enhanced photoelectrochemical water splitting

During the past few decades, photoelectrochemical (PEC) water splitting has attracted significant attention because of the reduced production cost of hydrogen obtained by utilizing solar energy. Significant efforts have been invested by the scientific community to produce stable ternary metal oxide semiconductors, which can enhance the stability and increase the overall production of oxygen. Herein, we present the ternary metal oxide deposition of ZnCo₂O₄ as a route to obtain a novel photocatalyst layer on BiVO₄ to form BiVO₄/ZnCo₂O₄ a novel composite photoanode for PEC water splitting. The structural, topographical, and optical analyses were performed using field emission scanning electron microscopy, X-ray diffraction, high-resolution transmission electron microscopy, and UV-Vis spectroscopy to confirm the structure of the ZnCo₂O₄ grafted over BiVO₄. A remarkable 4.4-fold enhancement of the photocurrent was observed for the BiVO₄/ZnCo₂O₄ composite compared with bare BiVO₄ under visible illumination. The optimum loading of ZnCo₂O₄ over BiVO₄ yields unprecedented stable photocurrent density with an apparent cathodic shift of 0.46 V under 1.5 AM simulated light illumination. This is also evidenced by the flat-band potential change through Mott-Schottky analysis, which reveals the formation of p-ZnCo₂O₄ on n-BiVO₄. The improvement in the PEC performance of the composite with respect to bare BiVO₄ is ascribed to the formation of thin passivating layer of p-ZnCo₂O₄ on n-BiVO₄ which improves the kinetics of interfacial charge transfer. Based on our study, we have gained an in-depth understanding of the BiVO₄/ZnCo₂O₄ composite as high potential in efficient PEC water splitting devices.

Molybdenum disulfide nanosheets vertically grown on self-supported titanium dioxide/nitrogen-doped carbon nanofiber film for effective hydrogen peroxide decomposition and "memory catalysis"

A self-supporting catalyst consisting of 1D/2D vertical molybdenum disulfide@titanium dioxide/nitrogen-doped carbon nanofiber (MoS₂@TiO₂/NCNFs) was prepared and tested. It showed efficient hydrogen peroxide (H₂O₂) decomposition to generate hydroxyl radical (OH) and degradation of various pollutants under solar irradiation. The contribution of the increase in MoS₂ edges for decomposing H₂O₂ was 0.0698 min^-1. That is 9.83 times the rate of the original MoS₂ edges resulting from the vertical structure. Specially, the catalyst degraded various aromatic pollutants even in the dark by releasing electrons stored in its graphite component to realize "memory catalysis". Also, it exhibited high degradation efficiency under outdoor solar irradiation. The catalyst was easily separated from the treated water, avoiding complex separation processes. All these features suggest this catalyst has great potential in practical water and sewage treatment applications.

Rational Synthesis of 1D Hyperbranched Heterostructures with Enhanced Optoelectronic Performance

One-dimensional (1D) hyperbranched heterostructures (HBHSs) with abundant interfaces are rendered with various interfacial phenomena and functionalities. However, the rational synthesis of 1D HBHSs with desired spatial architecture and specific interface remains a great challenge. Here, we report a seeded growth method for controlled synthesis of two extraordinary types of HBHSs, in which high-intensity of CdS branches selectively grow on 1D nanowire (NW) trunks with different growth behaviors. The composition of the HBHSs can be further tuned by combining with cation exchange method, which enriches the variety of the HBHSs. The optoelectronic devices based on a single HBHS were fabricated and exhibit a better photoresponse performance compared with that of a single NW trunk. This advance provides a strategy for the controlled synthesis HBHSs with complex morphology and offers a platform for exploring their applications for photo harvesting and conversion.

Exfoliated Ultrathin ZnIn2 S4 Nanosheets with Abundant Zinc Vacancies for Enhanced CO2 Electroreduction to Formate

Electrocatalytic conversion of carbon dioxide (CO₂ ) is promising for balancing carbon cycles while producing value-added feedstocks. Herein, ultrathin ZnIn₂ S₄ nanosheets with abundant Zn vacancies are demonstrated for electrochemically reducing CO₂ to formate. Specifically, a partial current density of 245 mA cm^-2 with a near-unity faradaic efficiency of 94 % for formate generation was achieved over the ultrathin ZnIn₂ S₄ nanosheets in a flow cell configuration. Experimental and theoretical results revealed that abundant Zn vacancies in the ultrathin ZnIn₂ S₄ nanosheets with a high electrochemically active surface area synergistically optimized the intermediate binding energy and contributed to the boosted selectivity and activity. This work may provide useful understandings in designing efficient catalysts for selective CO₂ electroreduction.

Tuning the Crystallinity and Coverage of SiO2-ZnIn2S4 Core-Shell Nanoparticles for Efficient Hydrogen Generation

The coverage, thickness, and crystallinity of ZnIn₂S₄ (ZIS) shells on SiO₂ core nanoparticles (SiO₂@ZIS) were systematically investigated using microwave-assisted solvothermal methods aided by the addition of acid in ethanolic medium. The surface modification of the SiO₂ cores with (3-mercaptopropyl)trimethoxysilane was found to be critical to generate a homogeneous coverage of ZnIn₂S₄. The SiO₂@ZIS core-shell nanoparticles exhibited the best coverage but poor crystallinity when synthesized in pure ethanol, whereas best crystallinity but poor coverage was observed when synthesized in an aqueous solution. The addition of selected amounts of acid (HCl) led to improved crystallinity in the ethanolic medium. The thickness of the ZIS shell could be controlled in an ethanolic solution by judiciously varying the amounts of acid and the concentration of the ZIS precursor. Increasing the concentration of the ZIS precursor to twice the standard concentration in ethanolic solution with the addition of 100 μL of HCl afforded better crystallinity, homogeneous coverage, and optimal photocatalytic hydrogen production.

Preparation of SnIn4S8/TiO2 Nanotube Photoanode and Its Photocathodic Protection for Q235 Carbon Steel Under Visible Light

TiO₂ is an attractive semiconductor suitable for photocathodic protection, but its weak absorption of visible light and low quantum yield limit its usage. Here, a new heterostructured SnIn₄S₈ nanosheet/TiO₂ nanotube photoanode was prepared and its photocathodic protection performance was analyzed. SnIn₄S₈ nanosheets were uniformly deposited on the surface of the TiO₂ nanotube via a solvothermal treatment. The SnIn₄S₈/TiO₂ composite exhibited better photocathodic protection performance compared with pure TiO₂ nanotubes, owing to its good visible-light response and photogenerated carrier separation efficiency. Moreover, the composite exhibited a maximum photocurrent density of 100 μA cm^-2 for a 6 h solvothermal reaction under visible light irradiation. The negative shift of the photoinduced potential of Q235 carbon steel connected to the composite could reach 0.45 V versus SCE. Therefore, the SnIn₄S₈/TiO₂ composite can offer efficient photocathodic protection for Q235 carbon steel against corrosion in 3.5 wt% NaCl solution. This work provides a new approach for the development of high-efficient photoanode materials for the photocathodic protection of metals.

Thiol-initiated photocatalytic oxidative cleavage of the CC bond in olefins and its extension to direct production of acetals from olefins

Oxidative cleavage of a broad scope of olefins is realized over ZnIn₂S₄ under visible light, using air as oxidant and thiol as initiator. Coupled with the condensation between aldehydes/ketones and alcohols, this strategy can be used to yield acetals directly from olefins.

Supporting ultrathin “fish scale-like” BiOBr nanosheets on Bi6Mo2O15 sub-microwires for boosting photocatalytic performance

A BiOBr/Bi6Mo2O15 edge-on heterostructure with fast electron transport could improve interface conductivity and accelerate charge-separation efficiency.

Hierarchical core-shell heterostructures of ZnIn2S4 nanosheets on electrospun In2O3 nanofibers with highly enhanced photocatalytic activity

Well-designed heterostructure semiconductor photocatalysts can improve the activity of photocatalytic reactions. In this work, we constructed a series of hierarchical ZnIn₂S₄/In₂O₃ heterostructures by growing ultrathin two-dimensional ZnIn₂S₄ nanosheets onto one-dimensional In₂O₃ electrospun nanofibers and used them as photocatalysts for the efficient photoreduction of toxic Cr(VI). This structural design increased the specific surface area, promoted the separation of photogenerated electrons and holes, and provided more active sites for the catalytic reactions. Under visible light irradiation, the optimized ZnIn₂S₄/In₂O₃ photocatalyst showed the highest photocatalytic performance with 100% reduction efficiency for Cr(VI) (50 mg/L) within 90 min, which is much higher than pure In₂O₃ and ZnIn₂S₄. Additionally, the recycling tests and X-ray diffraction (XRD) characterization indicated the stability of the ZnIn₂S₄/In₂O₃ photocatalyst, making it a promising candidate for environmental remediation applications. Finally, the two active species (e^- and ·O₂^-) participating in the photoreduction process were determined via trapping experiments and electron spin resonance (ESR) spectroscopy. Finally, a possible mechanism for the ZnIn₂S₄/In₂O₃ heterojunction photocatalytic system was carefully determined.

Hierarchical Ag3PO4@ZnIn2S4 nanoscoparium: An innovative Z-scheme photocatalyst for highly efficient and predictable tetracycline degradation

Z-scheme photocatalyst preserved with superior oxidicability is an innovative photocatalyst system that can be used for efficient photocatalytic detoxification of antibiotics. In this study, Z-scheme Ag₃PO₄@ZnIn₂S₄ photocatalyst was constructed by decorating Ag₃PO₄ nanoparticles on ZnIn₂S₄ nanoscopariums. ZnIn₂S₄ nanoscopariums were prepared by self-templated strategy and given hierarchical structures. The hierarchical Ag₃PO₄@ZnIn₂S₄ provides more active sites for generating photogenerated carriers and large surface area for capturing tetracycline. The study results show that Ag₃PO₄@ZnIn₂S₄ performed excellently well in the photocatalytic degradation of tetracycline and also in protecting Ag₃PO₄ nanoparticles from photo-corrosion. The highest removal efficiency (up to 92.3%) was achieved from the optimal composites of Ag₃PO₄ and ZnIn₂S₄. In stability tests, Ag₃PO₄@ZnIn₂S₄ did not reduce the photocatalytic activity of degrading tetracycline after five successive runs. Active radical identification proves that the transfer behavior of electron and hole over Ag₃PO₄@ZnIn₂S₄ follows a direct Z-scheme mechanism. Furthermore, the transformation pathway for degrading tetracycline was proposed by combining the Fukui index prediction with Mass Spectra identification of intermediates. This work presents in-depth sights into a regulated degradation pathway from theoretical prediction and practical identification based on innovative Z-scheme photocatalyst.

Shedding Light on the Role of Misfit Strain in Controlling Core-Shell Nanocrystals

Heteroepitaxial modification of nanomaterials has become a powerful means to create novel functionalities for various applications. One of the most elementary factors in heteroepitaxial nanostructures is the misfit strain arising from mismatched lattices of the constituent parts. Misfit strain not only dictates epitaxy kinetics for diversifying nanocrystal morphologies but also provides rational control over materials properties. In recent years, advances in chemical synthesis along with the rapid development of electron microscopy and X-ray diffraction techniques have enabled a substantial understanding of strain-related processes, which offers theoretical foundation and experimental guidance for researchers to refine heteroepitaxial nanostructures and their properties. Herein, recent investigations on heterogeneous core-shell nanocrystals containing misfit strains are summarized, with a focus on the mechanistic understanding of strain and strain-induced effects such as tuning the epitaxial habit, modulating the optical emission, and enhancing the catalytic activity and magnetic coercivity.

Single crystalline quaternary sulfide nanobelts for efficient solar-to-hydrogen conversion

Although solar-driven water splitting on semiconductor photocatalysts is an attractive route for hydrogen generation, there is a lack of excellent photocatalysts with high visible light activity. Due to their tunable bandgaps suitable for superior visible-light absorption, copper-based quaternary sulfides have been the important candidates. Here, we first assessed the preferred facet of wurtzite Cu-Zn-In-S for photocatalytic hydrogen evolution reaction using the relevant Gibbs free energies determined by first principle calculation. We then developed a colloidal method to synthesize single crystalline wurtzite Cu-Zn-In-S nanobelts (NBs) exposing (0001) facet with the lowest reaction Gibbs energy, as well as Cu-Zn-Ga-S NBs exposing (0001) facet. The obtained single crystalline Cu-Zn-In-S and Cu-Zn-Ga-S NBs exhibit superior hydrogen production activities under visible-light irradiation, which is composition-dependent. Our protocol represents an alternative surface engineering approach to realize efficient solar-to-chemical conversion of single crystalline copper-based multinary chalcogenides.

Quaternary sulfides are important candidates for solar-to-H₂ conversion due to tunable bandgaps for controllable light absorption. Here, authors prepare single crystalline wurtzite Cu-Zn-In-S and Cu-Zn-Ga-S nanobelts with (0001) facets that show strong photocatalytic H₂ production performances.

Surface-Induced 2D/1D Heterostructured Growth of ReS2/CoS2 for High-Performance Electrocatalysts

Two-dimensional/one-dimensional (2D/1D) heterostructures have received much attention from researchers for their abundant catalytically active sites and low contact resistance due to formation of chemical bonds at the interface. The investigation of such heterostructures, however, is confined to lattice-matched materials, which severely limits the material candidates. Herein, we demonstrate a lattice-mismatched 2D/1D heterostructured electrocatalyst consisting of 2D ReS₂ nanosheets and 1D CoS₂ nanowires. We propose that the higher surface energy of the CoS₂ nanowire and the lattice mismatch between 1D and 2D units are crucial for the growth process of ReS₂ nanosheets. More importantly, the terminal S^2- exposed on the surface of CoS₂ nanowires serves not only as the nucleus of ReS₂ nanosheets but also as a bridge to enhance electron transport efficiency. Thus, the ReS₂/CoS₂ heterostructures show outstanding hydrogen evolution reaction performance. This work is of general interest for the design of complex multidimensional nano-heterostructures with outstanding functionalities.

Single-unit-cell-thick layered electrocatalysts: from synthesis to application

Electrocatalysts are critical for water splitting, carbon dioxide reduction, and zinc-air battery. However, the low-exposed surface areas of bulk electrocatalysts usually limit the complete utilization of active sites. Ultrathin electrocatalysts have noteworthy advantages in maximizing the use of active sites. Among the pioneering works on such performing catalysts, the development of single-unit-cell-thick layered electrocatalysts (STLEs) has attracted extensive attention owing to their superior specific surface area and large number of vacancies, which can provide abundant available surface active sites. Therefore, this minireview provides recent advances in STLE synthesis and applications, which are helpful for electrocatalysis-oriented researchers. Finally, the future perspectives and challenges for developing high-performance STLEs are proposed.