An integrated nanoplatform for theranostics via multifunctional core-shell ferrite nanocubes

Solvothermally Synthesized Nickel-Doped Marigold-Like SnS2 Microflowers for High-Performance Supercapacitor Electrode Materials

Two-dimensional transition-metal dichalcogenides (TMDs) have emerged as promising capacitive materials for supercapacitors owing to their layered structure, high specific capacity, and large surface area. Herein, Ni-doped SnS2 microflowers were successfully synthesized via a facile one-step solvothermal approach. The obtained Ni-doped SnS2 microflowers exhibited a high specific capacitances of 459.5 and 77.22 F g-1 at current densities of 2 and 10 A g-1, respectively, in NaClO4 electrolyte, which was found to be higher than that of SnS2-based electrodes in various electrolytes such as KOH, KCl, Na2SO4, NaOH, and NaNO3. Additionally, these microflowers demonstrate a good specific energy density of up to 51.69 Wh kg-1, at a power density of 3204 Wkg-1. Moreover, Ni-doped SnS2 microflowers exhibit a capacity retention of 78.4% even after 5000 cycles. Better electrochemical performance of the prepared electrode may be attributed to some important factors, including the utilization of a highly ionic conductive and less viscous NaClO4 electrolyte, incorporation of Ni as a dopant, and the marigold flower-like morphology of the Ni-doped SnS2. Thus, Ni-doped SnS2 is a promising electrode material in unconventional high-energy storage technologies.

Ag Modified SnS2 Monolayer as a Potential Sensing Material for C4F7N Decompositions: A Density Functional Theory Study

As the field of 2D materials rapidly evolves, substances such as graphene, metal dichalcogenides, MXenes, and MBenes have garnered extensive attention from scholars in the gas sensing domain due to their unique and superior properties. Based on first-principles calculations, this work explored the adsorption characteristics of both intrinsic and silver (Ag) doped tin disulfide (SnS2) toward the decomposition components of the insulating medium C4F7N (namely, CF4, C3F6, and COF2), encompassing the adsorption energy, charge transfer, density of state (DOS), band structure, and adsorption stability. The results indicated that Ag-doped SnS2 exhibited an effective and stable adsorption for C3F6 and COF2, whereas its adsorption for CF4 was comparatively weaker. Additionally, the potential for Ag-SnS2 in detecting C3F6 was highlighted, inferred from the contributions of the band gap variations. This research provides theoretical guidance for the application of Ag-SnS2 as a sensing material in assessing the operational status of gas-insulated equipment.

Recent progress in emerging two-dimensional organic-inorganic van der Waals heterojunctions

Two-dimensional (2D) materials have attracted significant attention in recent decades due to their exceptional optoelectronic properties. Among them, to meet the growing demand for multifunctional applications, 2D organic-inorganic van der Waals (vdW) heterojunctions have become increasingly popular in the development of optoelectronic devices. These heterojunctions demonstrate impressive capability to synergistically combine the favourable characteristics of organic and inorganic materials, thereby offering a wide range of advantages. Also, they enable the creation of innovative device structures and introduce novel functionalities in existing 2D materials, avoiding the need for lattice matching in different material systems. Presently, researchers are actively working on improving the performance of devices based on 2D organic-inorganic vdW heterojunctions by focusing on enhancing the quality of 2D materials, precise stacking methods, energy band regulation, and material selection. Therefore, this review presents a thorough examination of the emerging 2D organic-inorganic vdW heterojunctions, including their classification, fabrication, and corresponding devices. Additionally, this review offers profound and comprehensive insight into the challenges in this field to inspire future research directions. It is expected to propel researchers to harness the extraordinary capabilities of 2D organic-inorganic vdW heterojunctions for a wider range of applications by further advancing the understanding of their fundamental properties, expanding the range of available materials, and exploring novel device architectures. The ongoing research and development in this field hold potential to unlock captivating advancements and foster practical applications across diverse industries.

The photocatalytic reduction of U(VI) by Ag-doped SnS2 materials under visible light

Efficient degradation of uranium(VI) (U(VI)) in wastewater is an urgent problem because of the chemical toxicity and radiotoxicity. In this study, the Ag_x-SnS₂ photocatalysts were compounded by a simple hydrothermal method, effectively removing U(VI) under visible light in water. Compared with SnS₂, the results indicated that Ag_x-SnS₂ would decrease the crystallinity without destroying the crystal structure. Moreover, it has excellent photocatalytic performance on the degradation rate of U(VI). Ag_0.5-SnS₂ exhibited a prominent photocatalytic reduction efficiency of UO₂²⁺ of about 86.4% under optical light for 75 min. This was attributed to Ag-doped catalysts, which can narrow the band gap and enhance absorption in visible light. Meanwhile, the doping of Ag promoted the separation of photoinduced carriers, so that more photogenerated charges participated in the photocatalytic reaction. The stability and reusability were verified by the cycle test and the potential photocatalytic mechanism was analyzed based on the experiment.

Synergistically Accelerating Adsorption-Electrocataysis of Sulfur Species via Interfacial Built-In Electric Field of SnS2 -MXene Mott-Schottky Heterojunction in Li-S Batteries

Developing efficient heterojunction electrocatalysts and uncovering their atomic-level interfacial mechanism in promoting sulfur-species adsorption-electrocatalysis are interesting yet challenging in lithium-sulfur batteries (LSBs). Here, multifunctional SnS₂ -MXene Mott-Schottky heterojunctions with interfacial built-in electric field (BIEF) are developed, as a model to decipher their BIEF effect for accelerating synergistic adsorption-electrocatalysis of bidirectional sulfur conversion. Theoretical and experimental analysis confirm that because Ti atoms in MXene easily lost electrons, whereas S atoms in SnS₂ easily gain electrons, and under Mott-Schottky influence, SnS₂ -MXene heterojunction forms the spontaneous BIEF, leading to the electronic flow from MXene to SnS₂ , so SnS₂ surface easily bonds with more lithium polysulfides. Moreover, the hetero-interface quickly propels abundant Li⁺ /electron transfer, so greatly lowering Li₂ S nucleation/decomposition barrier, promoting bidirectional sulfur conversion. Therefore, S/SnS₂ -MXene cathode displays a high reversible capacity (1,188.5 mAh g^-1 at 0.2 C) and a stable long-life span with 500 cycles (≈82.7% retention at 1.0 C). Importantly, the thick sulfur cathode (sulfur loading: 8.0 mg cm^-2 ) presents a large areal capacity of 7.35 mAh cm^-2 at lean electrolyte of 5.0 µL mg_s ^-1 . This work verifies the substantive mechanism that how BIEF optimizes the catalytic performance of heterojunctions and provides an effective strategy for deigning efficient bidirectional Li-S catalysts in LSBs.

A novel electrochemical immunosensor based on SnS2/NiCo metal-organic frameworks loaded with gold nanoparticles for cortisol detection

In this work, a label-free electrochemical immunosensor using tin sulfide/nickel cobalt metal-organic frameworks (SnS₂/NiCo MOFs) was established for the sensitive etection of cortisol. First, SnS₂/NiCo MOFs were synthesized by doping SnS₂ with NiCo MOF nanocubes by a hydrothermal method. Then, gold nanoparticles (AuNPs) were grown in situ on SnS₂/NiCo MOFs for electrochemical detection. The use of SnS₂/NiCo MOFs promoted the electron transfer rate of AuNPs and enhanced the electrochemical sensing performance of AuNPs@SnS₂/NiCo MOFs-modified electrodes. The large specific surface area of AuNPs@SnS₂/NiCo MOFs provides more active sites for antibody loading. After the prepared immunosensor was incubated with the target analyte, cortisol, the electron transfer impedance increased and the amperometric response decreased, thus establishing a highly sensitive immunosensing method. The sensor had a linear range of 100 fg/mL to 100 ng/mL and a low detection limit of 29 fg/mL. The sensor showed good accuracy and practicability and could be used for the determination of cortisol in saliva.

Hydrothermally synthesized nanocrystalline photoactive SnS2 thin films: effect of surface directing agents

In the present work, we have synthesized tin disulphide (SnS2) thin films via a facile, low cost, single-step hydrothermal route using various surface directing agents.

Ag functionalized SnS2 with enhanced photothermal activity for safe and efficient wound disinfection

Severe bacterial infections have brought an urgent threat to our daily life, and photothermal therapy (PTT) has acted as an effective method to kill bacteria. Herein we decorated Ag on the surface of SnS₂ (Ag@SnS₂), which has outstanding photothermal conversion capability and good biocompatibility. The decoration of Ag on SnS₂ improved the absorption of near-infrared (NIR) light in comparison to SnS₂, resulting in a temperature increase of 50 °C after 5 min of NIR light irradiation (1.9 W cm^-2) and a photothermal conversion efficiency of 31.3%. Ag@SnS₂ exhibits almost 100% growth inhibition of E. coli and S. aureus bacteria due to hyperthermia, with a concentration larger than 0.5 mg mL^-1 and 5 min of NIR irradiation. Meanwhile, SEM images of treated bacterial cells showed the attachment of Ag@SnS₂ on the cell surface and obvious cellular membrane destruction. Ag@SnS₂ can also accelerate in vivo wound healing through PTT-induced bacterial disinfection. Therefore, Ag@SnS₂ exhibits great potential for photothermal antibacterial application and wound disinfection.

Fabrication of the novel Ag-doped SnS2@InVO4 composite with high adsorption-photocatalysis for the removal of uranium (VI)

A novel Ag-doped SnS₂@InVO₄ composite was successfully synthesized for efficient uranium removal from wastewater through a facile hydrothermal method. The structure, morphology and optical property of materials were characterized using various instruments. The results proved that Ag-doped SnS₂@InVO₄ composite presented as hexangular nanosheets with about 4.87 nm pore size and 101.58 m²/g specific surface area. Further characterization demonstrated that photo-adsorption ability of visible light was enhanced and band gap was narrowed. The adsorption kinetics and isotherm of U(VI) on Ag-doped SnS₂@InVO₄ composite could be depicted via the Langmuir model and pseudo-second-order mode, and the maximum adsorption capacity of U(VI) reached 167.79 mg/g. The elimination of U(VI) of as-synthesized composites was studied by a synergy of adsorption and visible-light photocatalysis, and the optimal content of InVO₄ was found to be 2 wt% with the highest removal efficiency of 97.6%. In addition, compared with pure SnS₂ and Ag-doped SnS₂, the Ag-doped SnS₂@InVO₄ composites exhibited superior photocatalytic performance for the conversion of soluble U(VI) to insoluble U(IV) under visible light. The excellent photocatalytic performance was mainly attributed to numerous surface-active sites, strong optical adsorption ability and narrow band gap. Simultaneously, the heterojunction between Ag-doped SnS₂ and InVO₄ promoted the separation and transfer of photoexcited charges. The cyclic experiments indicated the Ag-doped SnS₂@InVO₄ composite remained good structural stability and reusability. Finally, the possible mechanism was discussed based on the experimental analysis.

Surface Nitrogen-Injection Engineering for High Formation Rate of CO2 Reduction to Formate

In this study, we highlight that surface nitrogen-injection engineering brings a high formation rate for CO₂ reduction to formate, which is high level among the reported electrocatalysts. Surface nitrogen-injection engineering can increase the amounts of active sites and optimize the electronic structure simultaneously. Taking an example of SnS₂ precursors, the final-obtained surface N-enriched Sn(S) nanosheets (denoted as N-Sn(S) nanosheets) exhibit a 5-fold of current density and 2.45-fold of Faradaic efficiency than pristine SnS₂ derived Sn(S) nanosheets (denoted as Sn(S) nanosheets). On account of high activity and selectivity, the formation rate of formate is 14 times than that of pristine samples and reaches up to 1358 μmol h^-1 cm^-2. Moreover, this strategy is proven to be general to other metal sulfides, such as CuS and In₂S₃. We anticipate that surface nitrogen-injection engineering offers new avenues to rational design of advanced electrocatalysts for CO₂ reduction reaction.

In situ growth of well-aligned Ni-MOF nanosheets on nickel foam for enhanced photocatalytic degradation of typical volatile organic compounds

Exploitation of highly efficient catalysts for photocatalytic degradation of volatile organic compounds (VOCs) under visible light irradiation is highly desirable yet challenging. Herein, well-aligned 2D Ni-MOF nanosheet arrays vertically grown on porous nickel foam (Ni-MOF/NF) without lateral stacking were successfully prepared via a facile in situ solvothermal strategy. In this process, Ni foam could serve as both a skeleton to vertically support the Ni-MOF nanosheets and a self-sacrificial template to afford Ni ions for MOF growth. The Ni-MOF/NF nanosheet arrays with highly exposed active sites and light harvesting centres as well as fast mass and e- transport channels exhibited excellent photocatalytic oxidation activity and mineralization efficiency to typical VOCs emitted from the paint spray industry, which was almost impossible for their three-dimensional (3D) bulk Ni-MOF counterparts. A mineralization efficiency of 86.6% could be achieved at 98.1% of ethyl acetate removal. The related degradation mechanism and possible reaction pathways were also attempted based on the electron paramagnetic resonance (EPR) and online Time-of-Flight Mass Spectrometer (PTR-ToF-MS) results.

Cobalt-doping SnS2 nanosheets towards high-performance anodes for sodium ion batteries

Layered SnS₂ is considered as a promising anode candidate for sodium-ion batteries yet suffers from low initial coulombic efficiency, limited specific capacity and rate capability. Herein, we report a cobalt metal cation doping strategy to enhance the electrochemical performance of a SnS₂ nanosheet array anode through a facile hydrothermal method. Benefitting from this special structure and heteroatom-doping effect, this anode material displays a high initial coulombic efficiency of 57.4%, a superior discharge specific capacity as high as 1288 mA h g^-1 at 0.2 A g^-1 after 100 cycles and outstanding long-term cycling stability with a reversible capacity of 800.4 mA h g^-1 even at 2 A g^-1. These excellent performances could be ascribed to the Co-doping effect that can increase the interlayer spacing, produce rich defects, regulate the electronic environment and improve conductivity. Besides, a carbon cloth substrate can maintain the integrity of the electrode material framework and buffer its volume variation, thus boosting intrinsic dynamic properties and enhancing sodium storage performance.

Fabrication of a counter electrode for dye-sensitized solar cells (DSSCs) using a carbon material produced with the organic ligand 2-methyl-8-hydroxyquinolinol (Mq)

Dye sensitized solar cells (DSSCs) are low cost solar cells and their fabrication process is easy relative to silicon based solar cells. Platinum can be replaced with carbon materials as counter electrodes in DSSCs because of their good catalytic properties and low cost. A carbon material was produced by carbonization of an organic ligand (2 methyl 8-hydroxy quinolinol (Mq)) at high temperature in flowing argon gas. Polyvinylpyrrolidone (PVP) was used as a surfactant for making carbon slurry from carbon produced using Mq. For the fabrication of the counter electrode, a carbon coating was prepared by using the doctor blading technique and the carbon slurry was coated on the FTO substrate. DSSCs based on the carbon counter electrode exhibit a higher V oc of 0.75 V than that of the Pt counter electrode (0.69 V). DSSCs based on the carbon material showed a power conversion efficiency (PCE) of 4.25% and fill factor (FF) of 0.51 which are slightly lower than those of the platinum (Pt) based counter electrode which showed a PCE of 5.86% and FF of 0.68.

Photoelectrochemical biosensor for CEA detection based on SnS2-GR with multiple quenching effects of Au@CuS-GR

A novel signal on-off type photoelectrochemical (PEC) biosensing system was designed for sensitive detection of carcinoembryonic antigen (CEA) based on tin disulfide nanosheets loaded on reduced graphene cxide (SnS₂-GR) as the photoactive material and gold nanoparticles coated on reduced graphene oxide-functionalized copper sulfide (Au@CuS-GR) for signal amplification. It's the first time for SnS₂-GR was exploited as a sensing matrix. Here, the photocurrent signals of SnS₂ were amplified attributed to the sensitization effect of graphene. As signal amplifier, Au@CuS-GR could quench the photocurrents of SnS₂-GR not only through the p-n type semiconductor quenching effect as well as the steric hindrance effect, but also as peroxidase mimetics to catalyze the oxidation of 4-Chloro-1-naphthol (4-CN) to produce insoluble product on the electrode surface. Based on the multiple signal amplification ability of Au@CuS-GR, CEA was detected sensitively with a linear range from 0.1 pg mL^-1 to 10 ng mL^-1 and limit of detection down to 59.9 fg mL^-1 (S/N = 3). Meanwhile, the PEC biosensor displayed excellent performance in the assay of human serum sample, showing good application prospects for various target analysis.

Cobalt Nanoparticles Embedded into N-Doped Carbon from Metal Organic Frameworks as Highly Active Electrocatalyst for Oxygen Evolution Reaction

Cystosepiment-like cobalt nanoparticles@N-doped carbon composite named Co-NPs@NC with highly efficient electrocatalytic performance for oxygen evolution reaction was prepared from carbonization of N-doped Co-MOFs. The optimized Co-NPs@NC-600 shows overpotentials of 315 mV to afford a current density of 10 mA·cm-2. Meanwhile, the electrocatalys presents excellent long-term durability. The outstanding electrocatalytic performance can be attributed to the unique cystosepiment-like architecture with high specific surface area (214 m2/g), high conductivity of N-doped carbon and well-distributed active sites.

Construction of uniform Co-Sn-X (X = S, Se, Te) nanocages with enhanced photovoltaic and oxygen evolution properties via anion exchange reaction

The development of highly efficient electrocatalysts has attracted increasing attention in the field of electrochemical energy conversion. Therefore, we report a simple self-template method to construct Co-Sn-X (X = S, Se, Te) nanocages through the anion exchange reaction of CoSn(OH)6 nanocubes with chalcogenide ions under mild solvothermal conditions. Benefiting from advantageous compositional features and well-designed architectures, the obtained Co-Sn-X (X = S, Se, Te) nanocages display enhanced electrocatalytic activity for dye-sensitized solar cells (DSSCs) and the oxygen evolution reaction (OER) in an alkaline electrolyte. Remarkably, the Co-Sn-Se nanocages as the counter electrode (CE) catalyst deliver a prominent power conversion efficiency (PCE) of 9.25% for DSSCs compared with Pt CE (8.19%). Furthermore, when used as an OER catalyst, the Co-Sn-Se nanocages also exhibit outstanding electrocatalytic activity in terms of their low overpotential of 304 mV at the current density of 10 mA cm-2 and long-term stability in 1.0 M KOH solution. This work provides wide prospects for the rational design and synthesis of high-performance transition metal chalcogenide-based electrocatalysts for future energy conversion systems.

Dye-Sensitized Solar Cells: Fundamentals and Current Status

Dye-sensitized solar cells (DSSCs) belong to the group of thin-film solar cells which have been under extensive research for more than two decades due to their low cost, simple preparation methodology, low toxicity and ease of production. Still, there is lot of scope for the replacement of current DSSC materials due to their high cost, less abundance, and long-term stability. The efficiency of existing DSSCs reaches up to 12%, using Ru(II) dyes by optimizing material and structural properties which is still less than the efficiency offered by first- and second-generation solar cells, i.e., other thin-film solar cells and Si-based solar cells which offer ~ 20-30% efficiency. This article provides an in-depth review on DSSC construction, operating principle, key problems (low efficiency, low scalability, and low stability), prospective efficient materials, and finally a brief insight to commercialization.

Low-Frequency Raman Spectroscopy of Few-Layer 2H-SnS2

We investigated interlayer phonon modes of mechanically exfoliated few-layer 2H-SnS2 samples by using room temperature low-frequency micro-Raman spectroscopy. Raman measurements were performed using laser wavelengths of 441.6, 514.4, 532 and 632.8 nm with power below 100 μW and inside a vacuum chamber to avoid photo-oxidation. The intralayer Eg and A1g modes are observed at ~206 cm-1 and 314 cm-1, respectively, but the Eg mode is much weaker for all excitation energies. The A1g mode exhibits strong resonant enhancement for the 532 nm (2.33 eV) laser. In the low-frequency region, interlayer vibrational modes of shear and breathing modes are observed. These modes show characteristic dependence on the number of layers. The strengths of the interlayer interactions are estimated by fitting the interlayer mode frequencies using the linear chain model and are found to be 1.64 × 1019 N · m-3 and 5.03 × 1019 N · m-3 for the shear and breathing modes, respectively.

High-performance dye-sensitized solar cells using Ag-doped CoS counter electrodes

CoS has been emerging as a promising Pt-free counter electrode (CE) material for dye-sensitized solar cells (DSSCs) due to its satisfactory electrocatalytic properties for redox reactions. However, its low electronic and ionic conductivities have limited its use in DSSCs. The doping of Ag with appropriate amount significantly improved the properties of CoS for application as a CE. Ag-doped CoS samples with various doping amounts were prepared by a facile one-step hydrothermal approach. There were very sharp changes of morphologies and particle sizes after doping different amounts of Ag. It is found that the DSSC fabricated with the 5% Ag-doped CoS CE achieved an impressive power-conversion efficiency (PCE) of 8.35% which was higher than that of the DSSC with a Pt CE (8.17%) by 2.2%, while the DSSC consisting of undoped CoS only exhibited a PCE of 6.93%. Such an enhanced PCE could be attributed to the significantly improved electrochemical activity and mixed conductivity resulting from the Ag dopant. Therefore, the excellent electrocatalytic activity, facile preparation and low material cost of the Ag-doped CoS electrode provide it with promising potential for large-scale production of new-generation DSSCs.

Facile Synthesis of SnS2 Nanostructures with Different Morphologies for High-Performance Supercapacitor Applications

SnS₂ is an emerging candidate for an electrode material because of the considerable interlayer spaces in its crystal structures and the large surface area. SnS₂ as a photocatalyst and in lithium ion batteries has been reported. On the other hand, there are only a few reports of their supercapacitor applications. In this study, sheetlike SnS₂ (SL-SnS₂), flowerlike SnS₂ (FL-SnS₂), and ellipsoid-like SnS₂ (EL-SnS₂) were fabricated via a facile solvothermal route using different types of solvents. The results suggested that the FL-SnS₂ exhibited better capacitive performance than the SL-SnS₂ and EL-SnS₂, which means that the morphology has a significant effect on the electrochemical reaction. The FL-SnS₂ displayed higher supercapacitor performance with a high capacity of approximately ∼431.82 F/g at a current density of 1 A/g. The remarkable electrochemical performance of the FL-SnS₂ could be attributed to the large specific surface area and better average pore size. These results suggest that a suitable solvent is appropriate for the large-scale construction of SnS₂ with different morphologies and also has huge potential in the practical applications of high-performance supercapacitors.

Ultrathin Nanosheet Assembled Sn0.91 Co0.19 S2 Nanocages with Exposed (100) Facets for High-Performance Lithium-Ion Batteries

Ultrathin 2D inorganic nanomaterials are good candidates for lithium-ion batteries, as well as the micro/nanocage structures with unique and tunable morphologies. Meanwhile, as a cost-effective method, chemical doping plays a vital role in manipulating physical and chemical properties of metal oxides and sulfides. Thus, the design of ultrathin, hollow, and chemical doped metal sulfides shows great promise for the application of Li-ion batteries by shortening the diffusion pathway of Li ions as well as minimizing the electrode volume change. Herein, ultrathin nanosheet assembled Sn_0.91 Co_0.19 S₂ nanocages with exposed (100) facets are first synthesized. The as-prepared electrode delivers an excellent discharge capacity of 809 mA h g^-1 at a current density of 100 mA g^-1 with a 91% retention after 60 discharge-charge cycles. The electrochemical performance reveals that the Li-ion batteries prepared by Sn_0.91 Co_0.19 S₂ nanocages have high capacity and great cycling stability.

Interconnected molybdenum disulfide@tin disulfide heterojunctions with different morphologies: a type of enhanced counter electrode for dye-sensitized solar cells

The MoS₂@SnS₂ heterojunctions have been synthesized and displayed the enhanced performance due to the specific crystal structure.

Visible-light driven Photoelectrochemical Immunosensor Based on SnS2@mpg-C3N4 for Detection of Prostate Specific Antigen

Herein, a novel label-free photoelectrochemical (PEC) immunosensor based on SnS2@mpg-C3N4 nanocomposite is fabricated for the detection of prostate specific antigen (PSA) in human serum. Firstly, mesoporous graphite-like carbon nitride (mpg-C3N4) with carboxyl groups is synthesized successfully which possesses high specific surface area and large pore volume. Then, SnS2 as a typical n-type semiconductor with weak photoelectric conversion capability is successfully loaded on carboxylated mpg-C3N4 to form a well-matched overlapping band-structure. The as-synthesized SnS2@mpg-C3N4 nanocomposite performs outstanding photocurrent response under visible-light irradiation due to low recombination rate of photoexcited electron-hole pairs, which is transcend than pure SnS2 or pure mpg-C3N4. It is worth noting that SnS2@mpg-C3N4 nanocomposite is firstly employed as the photoactive material in PEC immunosensor area. The concentration of PSA can be analyzed by the decrease in photocurrent resulted from increased steric hindrance of the immunocomplex. Under the optimal conditions, the developed PEC immunosensor displays a liner photocurrent response in the range of 50 fg·mL-1 ~ 10 ng·mL-1 with a low detection limit of 21 fg·mL-1. Furthermore, the fabricated immunosensor with satisfactory stability, reproducibility and selectivity provides a novel method for PSA determination in real sample analysis.

Recent Progress in Metal-Organic Frameworks and Their Derived Nanostructures for Energy and Environmental Applications

Metal-organic frameworks (MOFs), as a very promising category of porous materials, have attracted increasing interest from research communities due to their extremely high surface areas, diverse nanostructures, and unique properties. In recent years, there is a growing body of evidence to indicate that MOFs can function as ideal templates to prepare various nanostructured materials for energy and environmental cleaning applications. Recent progress in the design and synthesis of MOFs and MOF-derived nanomaterials for particular applications in lithium-ion batteries, sodium-ion batteries, supercapacitors, dye-sensitized solar cells, and heavy-metal-ion detection and removal is reviewed herein. In addition, the remaining major challenges in the above fields are discussed and some perspectives for future research efforts in the development of MOFs are also provided.

Novel CoS2 embedded carbon nanocages by direct sulfurizing metal-organic frameworks for dye-sensitized solar cells

Owing to its excellent electrocatalytic properties, cobalt disulfide (CoS2) is regarded as a promising counter electrode (CE) material for dye-sensitized solar cells (DSSCs). However, hindered by its relatively poor electrical conductivity and chemical instability, it remains a challenge to apply it into high-performance DSSCs. In this work, we have developed novel CoS2 embedded carbon nanocages as a CE in DSSCs, using ZIF-67 (zeolitic imidazolate framework 67, Co(mim)2, mim = 2-methylimidolate) as a template. The CoS2 samples sulfurized for different time lengths are prepared through a facile solution process. It is found that the sulfurization time can be optimized to maximize the DSSC efficiency and the DSSC based on the CoS2 embedded carbon nanocages sulfurized for 4 hours exhibits the highest photovoltaic conversion efficiency (PCE) of 8.20%, higher than those of DSSCs consisting of other CoS2 CEs and Pt-based DSSC (7.88%). The significantly improved DSSC PCE is contributed by the synergic effect of inner CoS2 nanoparticles and an amorphous carbon matrix, leading to a CE with high catalytic activity, good electrical conductivity and excellent durability. This study demonstrates that the CE based on inexpensive CoS2 embedded carbon nanocages is a prospective substitute to expensive platinum and provides a new approach for commercializing high-efficiency DSSCs.

SnS2nanoflakes for efficient humidity and alcohol sensing at room temperature

We report a one step facile hydrothermal synthesis of layered SnS₂nanoflakes and its application as humidity and alcohol sensor.

Effect of dopant concentration on visible light driven photocatalytic activity of Sn1−xAgxS2

An optimal amount of Ag doping can effectively increase the photocatalytic performance of SnS₂.