Heterojunction Composites Research Articles

Spark Plasma Sintering-Assisted Synthesis of Bi2Fe4O9/Bi25FeO40 Heterostructures with Enhanced Photocatalytic Activity for Removal of Antibiotics.

Bismuth ferrite-based heterojunction composites have been considered as promising visible-light responsive photocatalysts because of their narrow band gap structure; however, the synthetic methods reported in the literature were usually time-consuming. In this study, we report a facile and quick preparation of bismuth ferrite-based composites by the hydrothermal method, combined with spark plasma sintering (SPS), a technique that is usually used for the high-speed consolidation of powders. The result demonstrated that the SPS-assisted synthesized samples possess significant enhanced photoelectric and photocatalytic performance. Specifically, the SPS650 (sintered at the 650 °C for 5 min by SPS) exhibits a 1.5 times enhancement in the photocurrent density and a 3.8 times enhancement in the tetracycline hydrochloride photodegradation activity than the unmodified bismuth ferrite samples. The possible influence factors of SPS on photoelectric and photocatalytic performance of bismuth ferrite-based composites were discussed carefully. This study provides a feasible method for the facile and quick synthesis of a highly active bismuth ferrite-based visible-light-driven photocatalyst for practical applications.

One-pot hydrothermal in situ growth of In4SnS8@MoS2@CNTs as efficient Pt-free counter electrodes for dye-sensitized solar cells

Developing a synthesis method for large-scale preparation of efficient and economical non noble metal counter electrode (CE) electrocatalytic materials with good catalytic ability and stability is an ideal choice for the commercialization of dye-sensitized solar cells (DSSCs). In this paper, a novel micro-nanostructured composite of CE was prepared by fixing the In4SnS8 and MoS2 on carbon nanotubes (CNTs) and using a one-step hydrothermal strategy. The devices based on the In4SnS8@MoS2@CNTs composite CE performs high power conversion efficiency of 8.72%, far more than that of the device with the control ones (7.57%). The In4SnS8@MoS2 composite were homogeneously distributed on the CNTs surface to form a new In4SnS8@MoS2@CNTs composite network heterojunction. This distinctive porous structure can provide greater contact area and electronic transmission channel to ensure fast charge transport of electrolyte. The prefect electrochemical properties of the In4SnS8@MoS2@CNTs CE for the I−/I3− electrolyte also have been demonstrated by a series of electrochemical tests. As a result, it can be considered that the In4SnS8@MoS2@CNTs will replace the Pt CE and has broad application prospects in DSSCs.

ZnFe2O4 Nanoparticles on ZIF-8-Derived ZnO for Enhanced Acetone Sensing

The development of uniform heterostructures for gas-sensing materials is promising to achieve both a fast response and recovery time at low gas levels and good selectivity at significantly high interference gas levels. Here we report the preparation of a ZIF-8-derived metal oxide semiconductor nanocomposite with a heterojunction structure and its application as acetone gas sensor. This heterojunction composite was fabricated through in situ growth of ZnFe2O4 nanoparticles (10–20 nm) on the outer surface of rhombic dodecahedral-shaped ZnO. Through the derivative strategy, the ZnFe2O4/ZnO heterojunction sensor had a high response value of 225 ± 15 and a fast response time of 6 s to 100 ppm of acetone at the optimum working temperature of 260 °C. Furthermore, the response value reached 5.1 for only 1.8 ppm of acetone even under extremely high humidity (85%). To obtain a demonstration of the concept, an in-depth investigation of the sensing performances and the microstructure and surface state of ZnO and ZnFe2O4/ZnO heterojunction materials was carried out. We found that the excellent acetone sensitivity enhancement could largely be attributed to the ultrahigh number of free electrons and the abundant active sites generated by the tightly bound n–n heterojunction structure of ZnFe2O4/ZnO and the morphological characteristics. The large specific surface area of every sensing domain was the secondary factor in enhancing the gas-sensing properties. It suggests that this design for fabricating uniform and sensitive gas sensors may facilitate potential applications in detecting acetone gas.

Rapid determination of SARS-CoV-2 nucleocapsid proteins based on 2D/2D MXene/P–BiOCl/Ru(bpy)32+ heterojunction composites to enhance electrochemiluminescence performance

At the end of 2019, the novel coronavirus disease 2019 (COVID-19), a cluster of atypical pneumonia caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has been known as a highly contagious disease. Herein, we report the MXene/P–BiOCl/Ru(bpy)32+ heterojunction composite to construct an electrochemiluminescence (ECL) immunosensor for SARS-CoV-2 nucleocapsid protein (CoVNP) determination. Two-dimensional (2D) material ultrathin phosphorus-doped bismuth oxychloride (P–BiOCl) is exploited and first applied in ECL. 2D architectures MXene not only act as “soft substrate” to improve the properties of P–BiOCl, but also synergistically work with P–BiOCl. Owing to the inimitable set of bulk and interfacial properties, intrinsic high electrochemical conductivity, hydrophilicity and good biocompatible of 2D/2D MXene/P–BiOCl/Ru(bpy)32+, this as-exploited heterojunction composite is an efficient signal amplifier and co-reaction accelerator in the presence of tri-n-propylamine (TPA) as a coreactant. The proposed MXene/P–BiOCl/Ru(bpy)32+-TPA system exhibits a high and stable ECL signal and achieves ECL emission quenching for “signal on-off” recognition of CoVNP. Fascinatingly, the constructed ECL biosensor towards CoVNP allows a wide linear concentration range from 1 fg/mL to 10 ng/mL and a low limit of detection (LOD) of 0.49 fg/mL (S/N = 3). Furthermore, this presented strategy sheds light on designing a highly efficient ECL nanostructure through the combination of 2D MXene architectures with 2D semiconductor materials in the field of nanomedicine. This ECL biosensor can successfully detect CoVNP in human serum, which can promote the prosperity and development of diagnostic methods of SARS-CoV-2.

Ni-NiS Heterojunction Composite-Coated Separator for High-Performance Lithium Sulfur Battery

The shuttle effect and slow REDOX kinetics of lithium polysulfides (LiPSs) lead to low sulfur utilization rate, short cycle life, poor rate performance, which hinder the application of Li–S batteries. Herein, the Ni-NiS/NCF heterojunction composite was prepared with multistage pore structure and a large specific surface area, which can effectively capture LiPSs, provide more active sites for catalyzing LiPSs. Moreover, due to the heterojunction structure of Ni-NiS, in which NiS can effectively capture and catalyze lithium polysulfide, and Ni can effectively accelerate the diffusion and charge transfer of lithium ions, the Ni-NiS/NCF heterojunction composite establishes a high ion and electron conduction network, so as to achieve efficient mass and charge transfer capacity. The mutual coordination of uniformly distributed Ni-NiS heterojunctions inhibits the shuttle effect of LiPSs. When the sulfur load is 1.8 mg/cm2, the initial capacity of the cell with Ni-NiS/NCF-coated separator at 1 C is 1109.6 mAh/g, and the final discharge capacity is maintained at 618.0 mAh/g after 300 cycles. At the same time, the reversible specific capacity was maintained at 674.0 mAh/g after 50 cycles even under high sulfur load.

Ball-milling fabrication of n-p heterojunctions Bi4O5Br2/α-MnS with strengthened photocatalytic removal of bisphenol A in a Z-Scheme model

In this investigation, α-MnS with a large magnetic moment was typically selected to modify Bi4O5Br2 to produce a train of binary n-p heterojunction composites Bi4O5Br2/α-MnS (BMS) through a facile mechanical ball-milling manner. These achieved composites were subsequently subjected to physicochemical properties analyses. It was confirmed that both expected components were present and integrated into heterojunction structures. An endocrine disruptor bisphenol A (BPA) was typically selected as a target contaminant to estimate photocatalytic degradation efficiency under visible light. Under the identical condition, composites BMS exhibited obviously improved degradation efficiencies. Notably, the best catalog, composite BMS0.05, displayed the best catalytic outcome with an apparent reaction rate constant of 2.67 times that of Bi4O5Br2, primarily ascribed to the strengthened visible-light absorption, suitable phase composition, and boosted generation of reactive radicals caused by efficient carries redistribution and segregation along the appropriate band alignment. In addition, some reaction parameters were varied to optimize such a photocatalytic system. Moreover, degradation pathways were speculated through intermediates detection. Eventually, a rational Z-scheme photocatalysis mechanism was proposed in the light of capture experiments and band structure estimation.

Silica sand-supported nano zinc oxide-graphene oxide composite induced rapid photocatalytic decolorization of azo dyes under sunlight and improved antimicrobial activity.

Here, silica sand-supported heterojunction composite of nano zinc oxide (nZnO) and graphene oxide nanosheet (nZnO-GO@SS) was prepared, and its potential as an efficient photocatalyst for the degradation of methylene blue (MB) and Rhodamine-B (Rh-B) under sunlight was demonstrated. Transmission electron microscopy confirmed the uniform distribution of spherically shaped nZnO of average size of approximately 8 nm over graphene oxide nanosheet (GO) in the composites. Photodegradation yields of 95.3% and 97.5% for 100 ppm of MB and Rh-B dye within 150 and 220 min, respectively, were achieved under sunlight by the prepared nanocatalyst (nZnO-GO), while sand microparticle-supported nanocatalyst (nZnO-GO@SS) demonstrated faster degradation of MB and Rh-B, i.e., within 120 and 160 min, respectively. Furthermore, when the recyclability of the photocatalyst was studied, the nZnO-GO exhibited more than 80% degradation efficiency after five cycles for both the dyes and nZnO-GO@SS demonstrated 10% higher (~90%) removal capability after five cycles of reuse. Furthermore, the antibacterial assay showed complete inactivation of Escherichia coli and Staphylococcus aureus bacterial strain by nZnO-GO@SS. Hence, our proposed strategy for the removal of toxic dyes from the aquatic environment under sunlight proved that sand microparticle-supported nanocatalyst (nZnO-GO@SS) might be a superior, cost-effective, and suitable photocatalytic system for industrial applications toward toxic dye removal and decontamination from industrial wastewater.

Microwave-assisted synthesis of porous heterojunction ZnO/ZnMn2O4 microrods for efficient degradation of organic pollutants

The ZnO/ZnMn 2 O 4 heterojunction photocatalysts are synthesized through microwave-assisted hydrothermal route, and show high photocatalytic activity towards methylene blue and methyl orange under UV light irradiation. • Microwave-assisted hydrothermal method is used to obtain porous heterojunction ZZMO. • The active species in the photocatalytic system are the O 2 − and h + by trapping experiments. • The enhanced catalytic activities of ZZMO result from the formation of n-p junction. • A maximum degradation of MB is estimated as ∼100% for optimized ZZMO within 60 min. • Photocatalytic degradation mechanism of hetero ZZMO towards organic dyes is proposed. Photocatalytic activity of a semiconductor with low band gap has been greatly suppressed due to the high recombination rate of photogenerated charge carriers. The most economic and efficient remedy is to construct a heterojunction to enhance the transfer/separation of interfacial charge carriers. Inspired by this, the rod-like ZnO/ZnMn 2 O 4 composite heterojunction photocatalysts are synthesized via a facile template-free microwave-assisted hydrothermal route. The photocatalytic activities of the as-prepared samples are evaluated by the photocatalytic degradation of methylene blue and methyl orange under UV light irradiation. The optimized ZnO/ZnMn 2 O 4 demonstrates enhanced photocatalytic efficiencies towards degradation of methylene blue and methyl orange, which are about 4.3 and 3.0 times higher than those of pure ZnO, respectively. Furthermore, the composite could still maintain good photocatalytic activity for photocatalytic methylene blue even after four recycles. The active species in the photocatalytic system are·O 2 − and h + , which can be confirmed by the trapping experiments. The enhanced photocatalytic activity of ZnO/ZnMn 2 O 4 composite may result from the formation of n-p junction, which supports the generation of·O 2 − and h + . More significantly, the intrinsic photocatalytic degradation mechanism of ZnO/ZnMn 2 O 4 composite towards organic dyes is tentatively proposed.

A comprehensive optimization of the sensitivity of CdS/CdIn2S4 composites to triethylamine gas

The physical and chemical properties of CdIn2S4 can be effectively regulated by changing the composition and phase structure to present a rich diversity, making it a potential new gas sensing material. However, CdIn2S4 has the characteristics of low carrier mobility and difficult separation of electrons and holes, which greatly hinders its development in the fields of gas sensing and catalysis. In this work, a sulfur-vacancy-rich CdS/CdIn2S4 heterojunction composite was constructed by a one-step hydrothermal method for gas sensing, and the built-in electric field was used to effectively promote the separation and transfer of charges. Moreover, the introduction of sulfur vacancies increases the content of chemisorbed oxygen, which provides more reactive sites for the target gas, thereby realizing the improvement of gas sensing performance. Compared with the CdIn2S4 sensor, the CdS/CdIn2S4 sensor exhibited higher response to triethylamine (10 ppm-32.5), faster response/recovery time (3 s/256 s) and achieved a lower limit of detection at the ppb level (500 ppb-5.2). This work provides a new solution for real-time monitoring of low-concentration triethylamine gas.

Fabrication of Cu2O/MTiO3 (M = Ca, Sr and Ba) p-n heterojunction for highly enhanced photocatalytic hydrogen generation

Herein, a binary Cu2O/MTiO3 (M = Ca, Sr and Ba) p-n heterojunction composites are successfully designed and prepared by the hydrothermal method and following NaBH4 reduction treatment. With the help of ethanediol and polyvinylpyrrolidone, it is found that Cu2O nanoparticles (NPs) can disperse evenly on the surface of CaTiO3. Excitingly, the highest H2 production rate (HPR) of the Cu2O/CaTiO3 samples is up to 8.268 mmol g−1 h−1, which is about 344.5 times as high as that of CaTiO3 sample under the same conditions. Compared with pure CaTiO3, the photoelectric chemical performance tests manifest that photocurrent density the of Cu2O/CaTiO3 composite increases and the interface resistance decreases. These results manifest that the construction of p-n heterojunction in Cu2O/CaTiO3 sample can improve the separation and migration rates of photogenerated carrier pairs, thus accelerating the generation of H2. Additionally, the Cu2O/CaTiO3 exhibits the best HPR as compared to Cu2O/SrTiO3 and Cu2O/BaTiO3 composites, which may be attributed to the more active sites in hollow CaTiO3. This work reports a viable strategy to fabricate the Cu2O/MTiO3 p-n heterojunction, which can overcome the boundedness of single Cu2O or MTiO3 in photocatalytic performance.

Design and construction of core-shelled Co3O4-CoFe2O4 heterojunction for highly sensitive and selective detection of ammonia

In this study, the fabrication process and the gas sensing performance toward ammonia of core-shelled Co3O4-CoFe2O4 heterojunction composites with the abundant mesoporous structures were presented detailedly. The hierarchical Co3O4-CoFe2O4 was prepared by using Fe-Co glycerate as a precursor combined with a subsequent thermolysis method. The well-designed core-shelled heterojunction architecture was investigated through SEM and TEM. Apparently, the internal and external structure of the glycerate-derived sensing materials can be efficiently regulated by adjusting the molar ratio of the Fe and Co in the precursor. It was worth pointing out that the core-shelled heterojunction structure possessed a large specific surface area (198.6 m2/g), which not only can provide more active sites in both interior and exterior of the composites sphere, but also accelerate absorption-penetration efficiency of gas molecules. Compared with other prepared nanoparticles and hollow spheres, the sensor fabricated by Co3O4-CoFe2O4 with a core–shell structure revealed the best sensing characteristics, and the response toward 100 ppm ammonia at 220 °C was as high as 35. Moreover, it also showed excellent selectivity and long-term stability. These admirable advancements can be ascribed to the synergistic effect of unique core–shell architecture and p-p heterojunction. This work may offer a promising strategy to realize the practical application of Co3O4-CoFe2O4 p-p heterojunction in ammonia detection.

Flower-like ZnO/BiOI p–n heterojunction composites for enhanced photodegradation of formaldehyde and dyes

Flower-like ZnO/BiOI p–n heterojunction composites for enhanced photodegradation of formaldehyde and dyes

Novel scheme towards interfacial charge transfer between ZnIn2S4 and BiOBr for efficient photocatalytic removal of organics and chromium (VI) from water.

Construction of Z-scheme heterostructure is an effective strategy to enhance the charge carriers' separation. However, successfully achieving this on the defect heterojunction to improve the photocatalytic activity remains challenging. This work successfully obtained sulfur vacancy in the ZnIn2S4/BiOBr (SZIS/BOB) heterojunction composites with S-O covalent bonding using a hydrothermal method. As a result, they exhibited superior photocatalytic and stability performance. The optimized SZIS/BOB-10 exhibited excellent rhodamine B degradation (95.2%) and chromium (VI) reduction (97.8%) within 100min under visible light. The enhanced composites with S-vacancies, S-O bond, and internal electric field induced the Z-scheme charge transfer mechanism. We had verified this mechanism based on the surface photovoltage spectra, electron spin response spectra, and density functional theory calculations. This work not only provides valuable insights into designing photocatalysts with a direct Z scheme heterostructure but also delineates a promising strategy for developing efficient photocatalysts to degrade organic pollutants.

Construction of hydrostable cesium lead bromide-titania for visible-light degradation of tetracycline hydrochloride in water

The poor stability of metal halide perovskite in water is one of the main obstacles restricting its practical application. Hydrostable cesium lead bromide-titania heterojunction was synthesized by the solvothermal method with the following sintering process and applied for the visible-light-driven photodegradation of tetracycline hydrochloride (TC-HCl) in water. The introduced TiO 2 components effectively protect CsPbBr 3 nanoparticles from phase transition which spurs significantly improved photocatalytic performance and stability on CsPbBr 3 –TiO 2 heterojunction in water. The structure of synthesized CsPbBr 3 –TiO 2 photocatalyst is characterized by XRD , SEM, and TEM . The photoelectric characteristics of prepared photocatalysts investigated through photoelectrochemical and photoluminescent analyses indicate that the enhanced photocatalytic property may be related to the optimized light response and electron-hole separation on heterojunction composites. The active substances in the photocatalytic process are determined through capture experiments, indicating that holes (h + ) and superoxide radicals (• O 2 − ) are responsible for photocatalytic activity . A reaction mechanism is suggested in the end. This work provides an alternative for the construction of water-resistant halide perovskite to break through the poor water stability and opens novel applications for halide perovskite-based materials in aqueous environmental control. Hydrostable CsPbBr 3 –TiO 2 composite has been successfully prepared by solvothermal method, which shows enhanced photocatalytic performance for visible-light degradation of tetracycline hydrochloride in an aqueous system with good stability. • Hydrostable CsPbBr 3 –TiO 2 composite is synthesized by solvothermal method. • CsPbBr 3 –TiO 2 shows prominent visible-light photodegradation of aqueous TC-HCl. • The photocatalytic activity and water resistance are related to CsPbBr 3 /TiO 2 ratios.

Fabricating of Ni-BTC/NiS2 heterostructure via self-assembly strategy for electrocatalytic methanol oxidation

A novel Ni-MOF/nickel disulfide heterojunction composite (Ni-BTC/NiS 2 ) has been constructed successfully via in situ self-assembly strategy for the first time, which exhibits excellent MOR activity and durability. • A heterojunction composite has been constructed via in situ self-assembly strategy. • Ni-BTC/NiS 2 composite exhibits excellent electrocatalytic properties for MOR. • This work provides a new vision for the design of MOR electrocatalysts. Nickel-based metal-organic frameworks (Ni-MOFs) are a promising anodic electrocatalyst for methanol oxidation reaction (MOR), but suffer from either low conductivity or poor chemical stability. The fabrication of MOF-based heterogeneous composites is one of the possible solutions. Herein, for the first time, a novel Ni-MOF/nickel disulfide heterojunction composite (Ni-BTC/NiS 2 ) has been constructed successfully via in situ self-assembly strategy, which exhibits excellent MOR activity and durability with an area specific peak current density of 34.36 mA cm −2 . The enhanced electrocatalytic performance of the composite might be attributed to the synergistic/interface effect derived from the heterojunction structure. Undoubtedly, the integration of MOFs and inorganic functional species within a heterostructure realized by this work provides a new vision for the design of MOF-based electrocatalysts for MOR and other energy conversion processes.

Z-scheme g-C3N4/ZnS heterojunction photocatalyst: One-pot synthesis, interfacial structure regulation, and improved photocatalysis activity for bisphenol A

Taguchi experiment was used to optimize the experimental conditions, including the dosage of precursor and calcination temperature, in order to controllably synthesize g-C3N4/ZnS heterojunction composites from zinc acetate (Zn(OAc)2) and thiourea (Tu) by facile one-pot annealing method. The photocatalytic activity of g-C3N4/ZnS heterojunction composites for bisphenol A (BPA) in aqueous solution was studied. The g-C3N4/ZnS composites prepared at the optimum conditions according to the results of Taguchi experiment (labeled as g-C3N4/ZnS-10) exhibited significantly improved removal rate of BPA (92.1% after 8 h), which was 7.4, 2.1 and 6.6 times higher than that of g-C3N4, ZnS and g-C3N4/ZnS-1 (the composites with the lowest photocatalytic activity in Taguchi experiment), respectively. g-C3N4/ZnS heterojunction composites was characterized by XRD, FT-IR, BET, SEM, TEM, EDS, XPS, PL, EPR, UV–vis DRS and UPS. The trapping experiment and DMPO spin-trapping experiment revealed that Superoxide radicals played a major role in the photocatalysis of BPA. The excellent photocatalytic activity of g-C3N4/ZnS-10 was mainly attributed to the synergistic effect which can create the internal driving force to enhance the light response and improve the separation/transfer efficiency of interfacial charge in Z-scheme heterojunction. The underlying photocatalytic mechanism was discussed and analyzed in details.

Electrical characterisation of photosensitive Si/W–Ge oxide composite heterojunction

Tungsten-germanium (W–Ge) oxide composite thin film was grown on the p-type Si wafer which already has an Al ohmic contact, with the co-deposition technique by using magnetron sputter method and Al/Si/W–Ge oxide composite heterojunction was fabricated. The active layer surface analysis was determined by Scanning electron microscopy (SEM) and it was observed that it has a homogeneous surface morphology. The distribution and weight percentage of elements that formed to thin film was determined by Energy dispersive X-ray spectrometry (EDX). It was found that W, Ge and O are homogenously distributed in the film. Electrical properties of fabricated heterojunction were characterised under forward and reverse bias at different light intensity. It was obtained that diode ideality factor (n) and series resistance (Rs) dropped up to 2.98 and 5Ω, respectively and also barrier height (∅b) took the values between 0.38 to 0.32eV. Additionally, photocurrent, photoresponsivity, photosensitivity and photovoltaic parameters of the heterojunction were calculated under different light intensity. It was determined that the heterojunction exhibited typical photodiode behaviour and the maximum fill factor (FF) value was 0.3084 under 60mW/cm2 light intensity.

Visible light assisted heterojunction composite of AgI and CDs doped ZIF-8 metal-organic framework for photocatalytic degradation of organic dye

• CDs@ZIF-8@AgI was prepared by a solvent-free way coupled to ion deposition strategy. • Acridine Orange can be effectively degraded by CDs@ZIF-8@AgI under visible light. Water pollution induced by the productive process of organic dyes would lead to various diseases, and so treatment of the wastewater is an urgent task for protecting human health and ecological environment. In this work, visible light responsive heterojunction material based on silver iodide and carbon dots (CDs) doped ZIF-8 metal organic frameworks (CDs@ZIF-8@AgI) has been prepared by a green solvent-free strategy and in-situ ion deposition method. The CDs@ZIF-8@AgI composites have high photocatalytic performance for degradation of acridine orange (AO) dye under visible light, and the maximum degradation percentage can reach to 96.0%, which was estimated by the UV-visible spectroscopy. The porous structure and large surface area of the photocatalyst were favorable to absorption of the target dye on the catalyst, which can promote the kinetic degradation rate for low level concentration of the dye. The introduction of CDs into the AgI heterojunction can improve the electron transport efficiency and visible light absorption capacity, and thus significantly enhancing the photocatalytic activity of the catalyst. The photocatalytic mechanism was proposed as indirect Z-scheme heterojunction type based on the energy band structure of the catalyst. This work provides a visible light photocatalyst for removal of the AO dye in wastewater and offers a promising strategy for developing photocatalyst for treatment of organic pollutants in the environment using solar energy.

Iron-tungsten oxides modified oxygen-rich carbon nitride with defects S-scheme heterojunction for boosting photo-Fenton like removal of pollutants

Owning to excellence of photocatalytic persulfate (PS)-based oxidation processes in pollutant removal, the iron-tungsten oxides modified oxygen-rich carbon nitride with defects (ITOs/OCNv) S-scheme heterojunction composites were successfully prepared, and the photo-Fenton like system (Vis/ITOs/OCNv/PS) was constructed to degrade antibiotic pollutants. Results indicated that the ITOs/OCNv composites exhibited large specific surface area and rich porous structure. In addition, the in-situ introduction of oxygen-rich functional groups and lots of N and O vacancy defects in the composites enhanced the absorption of visible light (Vis) and the electron transfer. Importantly, the formed S-scheme heterojunction improved the separation of photogenerated carriers. The degradation efficiencies of sulfamethazine (SMZ) and ciprofloxacin (CIP) in the optimal Vis/5% ITOs/OCNv/PS system were 99.6 % and 99.5 %, which were 1.69 and 2.34 times that of Vis/5% ITOs/OCNv system (SMZ 58.9 % and CIP 42.6 %) after 40 min, respectively. Results of quenching experiments showed that the main active species were h+, 1O2 and O2− for SMZ and CIP degradation. Moreover, this system exhibited better anti-interference of water substrates and applicability in actual water body. The degradation pathways of CIP were proposed by combining density functional theory calculation with intermediate analysis. Moreover, the ecotoxicities of CIP and its products were evaluated comprehensively. The system showed better broad-spectrum degradation of pollutants, including sulfamethoxazole, atrazine, sulfadimethoxine and bisphenol A, which would provide a new insight for persistent pollutant removal.

Metal Ion Cutting-Assisted Synthesis of Defect-Rich MoS2 Nanosheets for High-Rate and Ultrastable Li2S Catalytic Deposition.

Active metal ions often show a strong cutting effect on the chemical bonds during high-temperature thermal processes. Herein, a one-pot metal ion cutting-assisted method was adopted to design defect-rich MoS2-x nanosheet (NS)/ZnS nanoparticle (NP) heterojunction composites on carbon nanofiber skeletons (CNF@MoS2-x/ZnS) via a simple Ar-ambience annealing. Results show that Zn2+ ions capture S2- ions from MoS2 and form into ZnS NPs, and the MoS2 NSs lose S2- ions and become MoS2-x ones. As sulfur hosts for lithium-sulfur batteries (LSBs), the CNF@MoS2-x/ZnS-S cathodes deliver a high reversible capacity of 1233 mA h g-1 at 0.1 C and keep 944 mA h g-1 at 3 C. Moreover, the cathodes also show an extremely low decay rate of 0.012% for 900 cycles at 2 C. Series of analysis indicate that the MoS2-x NSs significantly improve the chemisorption and catalyze the kinetic process of redox reactions of lithium polysulfides, and the heterojunctions between MoS2-x NSs and ZnS NPs further accelerate the transport of electrons and the diffusion of Li+ ions. Besides, the CNF@MoS2-x/ZnS-S LSBs also show an ultralow self-discharge rate of 1.1% in voltage. This research would give some new insights for the design of defect-rich electrode materials for high-performance energy storage devices.