Biosensors Based on Advanced Sulfur-Containing Nanomaterials

In recent years, sulfur-containing nanomaterials and their derivatives/composites have attracted much attention because of their important role in the field of biosensor, biolabeling, drug delivery and diagnostic imaging technology, which inspires us to compile this review. To focus on the relationships between advanced biomaterials and biosensors, this review describes the applications of various types of sulfur-containing nanomaterials in biosensors. We bring two types of sulfur-containing nanomaterials including metallic sulfide nanomaterials and sulfur-containing quantum dots, to discuss and summarize the possibility and application as biosensors based on the sulfur-containing nanomaterials. Finally, future perspective and challenges of biosensors based on sulfur-containing nanomaterials are briefly rendered.

Recent Progress in Metal-Free Covalent Organic Frameworks as Heterogeneous Catalysts

Covalent organic frameworks (COFs), connecting different organic units into one system through covalent bonds, are crystalline organic porous materials with 2D or 3D networks. Compared with conventional porous materials such as inorganic zeolite, active carbon, and metal-organic frameworks, COFs are a new type of porous materials with well-designed pore structure, high surface area, outstanding stability, and easy functionalization at the molecular level, which have attracted extensive attention in various fields, such as energy storage, gas separation, sensing, photoluminescence, proton conduction, magnetic properties, drug delivery, and heterogeneous catalysis. Herein, the recent advances in metal-free COFs as a versatile platform for heterogeneous catalysis in a wide range of chemical reactions are presented and the synthetic strategy and promising catalytic applications of COF-based catalysts (including photocatalysis) are summarized. According to the types of catalytic reactions, this review is divided into the following five parts for discussion: achiral organic catalysis, chiral organic conversion, photocatalytic organic reactions, photocatalytic energy conversion (including water splitting and the reduction of carbon dioxide), and photocatalytic pollutant degradation. Furthermore, the remaining challenges and prospects of COFs as heterogeneous catalysts are also presented.

Unique Two-Dimensional Indium Telluride Templated by a Rare Wheel-Shaped Heterobimetallic Mn/In Cluster

A new indium telluride, [Mn_4.78In_2.22(ea)₁₂]_n[In_9.79Mn_0.21Te₁₇]_n (where Hea = ethanolamine), containing unprecedented nonsupertetrahedral [In_9.79Mn_0.21Te₂₁] units is the first example of a two-dimensional indium telluride framework templated by a rare high-nuclearity wheel-shaped heterometallic [Mn_4.78In_2.22(ea)₁₂]^4.22+ cluster. The photocurrent response and magnetic properties were investigated.

Metal Chalcogenides Based Heterojunctions and Novel Nanostructures for Photocatalytic Hydrogen Evolution

The photo-conversion efficiency is a key issue in the development of new photocatalysts for solar light driven water splitting applications. In recent years, different engineering strategies have been proposed to improve the photogeneration and the lifetime of charge carriers in nanostructured photocatalysts. In particular, the rational design of heterojunctions composites to obtain peculiar physico-chemical properties has achieved more efficient charge carriers formation and separation in comparison to their individual component materials. In this review, the recent progress of sulfide-based heterojunctions and novel nanostructures such as core-shell structure, periodical structure, and hollow cylinders is summarized. Some new perspectives of opportunities and challenges in fabricating high-performance photocatalysts are also discussed.

Surface defect engineering of mesoporous Cu/ZnS nanocrystal-linked networks for improved visible-light photocatalytic hydrogen production

Cu-doped ZnS nanocrystal-linked mesoporous frameworks possessing suitable electronic energy levels, strong visible-light absorption and large porosity with a low defective surface show efficient photocatalytic H₂ evolution activity from water splitting.

One-step, high-yield synthesis of g-C3N4 nanosheets for enhanced visible light photocatalytic activity

A facile template-free one-step synthesis method of ultrathin g-C₃N₄ nanosheets was developed through thermal polycondensation of melamine. The higher temperature, prolonged time and tightly sealed crucible reaction system contributed to the formation of ultrathin g-C₃N₄ nanosheets. The as-synthesized g-C₃N₄ nanosheets were applied to the visible light photocatalytic degradation of RhB. The photocatalytic activity was significantly enhanced with increased calcination temperature from 500 °C to 650 °C and prolonged calcination time from 4 h to 10 h. Interestingly, the obtained ultrathin g-C₃N₄ nanosheets simultaneously possess high yield and excellent photocatalytic activity. Moreover, g-C₃N₄ nanosheets can maintain photochemical stability after five consecutive runs. The remarkably enhanced photocatalytic activity can be interpreted as the synergistic effects of the enhanced crystallinity, the large surface area, the reduced layer thickness and size and the reduced number of defects. A new layer exfoliation and splitting mechanism of the formation of the ultrathin nanosheets was proposed. This work provides a new strategy to develop a facile eco-friendly template-free one-step synthesis method for potential large-scale synthesis of ultrathin nanosheets with high yield, high photocatalytic efficiency and stable activity for environmental and energetic applications.

Stepwise Conversion from GeO2 to [MGe4S10]n3n- (M = Cu, Ag) Polymer via Isolatable [Ge2S6]4- and [Ge4S10]4- Anions by Virtue of Templating Technique

Rational synthesis of inorganic matter remains a great challenge encountered with modern synthetic chemistry. Here we reported the stepwise solvothermal conversion from GeO₂ to [MGe₄S₁₀]_n^3n- (M = Cu, Ag) polymer via isolatable [Ge₂S₆]^4- and [Ge₄S₁₀]^4- anions by virtue of templating technique. The facile sulfuration of GeO₂ resulted in the methylammonium-templated dimeric thiogermanate [CH₃NH₃]₄Ge₂S₆ (1). This was used subsequently as a precursor for the formation of adamantane-like [Ge₄S₁₀]^4- cluster, which was isolated as a mixed methylammonium/ethylammonium salt [CH₃CH₂NH₃]₃[CH₃NH₃]Ge₄S₁₀ (2). Compound 2 was then successfully used as a precursor to react with Cu⁺ and Ag⁺ cations in the presence of tetraethylammonium, resulting in alternating copolymeric products [(CH₃CH₂)₄N]₃MGe₄S₁₀ (M = Cu (3), Ag (4)), whose anionic moieties feature a novel zigzag chainlike structure constructed by [Ge₄S₁₀]^4- clusters via two-coordinate Cu⁺/Ag⁺ linkers. Mixed amine/ethanol or deep eutectic solvents were applied as media for the syntheses of 1-4, and all the products were characterized in the solid state and solution. Crystal structural analysis of the title compounds revealed significant templating roles of the alkylammonium cations as both space-filling agents and hydrogen-bonding donors, suggesting the structure-directing mechanism for the species formation and crystal growth. The design and optimization of multistep structural conversion upon templating effects would be beneficial for drawing rational, predictable pathways for inorganic synthesis.

Interlinking supertetrahedral chalcogenolate clusters with bipyridines to form two-dimensional coordination polymers for photocatalytic degradation of organic dye

Chalcogenolate clusters Cd6Ag4(EPh)16(DMF)3(CH3OH) (E = S, Se) with supertetrahedral structures are isolated. Further interlinking the clusters with organic linker 4,4'-trimethylenedipiperidine in the stepwise assembly approach forms two-dimensional coordination polymers. The clusters and the coordination polymers show tunable band gaps and efficient photocatalytic activities for the degradation of aqueous dye solution. This study demonstrates the great potential of using chalcogenolate clusters and their coordination polymers in photocatalysis applications.

Solution-Based Synthesis and Processing of Metal Chalcogenides for Thermoelectric Applications

Metal chalcogenide materials are current mainstream thermoelectric materials with high conversion efficiency. This review provides an overview of the scalable solution-based methods for controllable synthesis of various nanostructured and thin-film metal chalcogenides, as well as their properties for thermoelectric applications. Furthermore, the state-of-art ink-based processing method for fabrication of thermoelectric generators based on metal chalcogenides is briefly introduced. Finally, the perspective on this field with regard to material production and device development is also commented upon.

Two rare-earth-based quaternary chalcogenides EuCdGeQ4 (Q = S, Se) with strong second-harmonic generation

Two RE-based quaternary metal chalcogenides EuCdGeQ₄ (Q = S, Se) are discovered. They possess many attractive properties as preferred IR NLO materials including large band gaps, phase-matched intense SHG and congruent melting behavior.

A new cluster-based chalcogenide zeolite analogue with a large inter-cluster bridging angle

A new cluster-based chalcogenide zeolite analogue with a large inter-cluster bridging angle.

Anti-Site Defects-Assisted Enhancement of Electrogenerated Chemiluminescence from in Situ Mn2+-Doped Supertetrahedral Chalcogenide Nanoclusters

Understanding and revealing the connection between defects and dopant for improving electrogenerated chemiluminescence (ECL) efficiency remain a constant challenge. In this work, the in situ Mn²⁺-doped Mn_1.36Zn_5.64In₂₈S₅₆ supertetrahedral chalcogenide semiconductor nanoclusters (NCs) with an ECL efficiency as high as 27.1% was obtained, the corresponding ECL behaviors were investigated, and the vital role of more anti-site defects (ADs) introduced in situ on the ECL emission was elucidated. The ADs can not only give rise to the ECL emission peak at 494 nm but also assist transfer of electrons to induce and enhance the ECL emission at 627 nm from doped Mn²⁺ in the NCs. Furthermore, based on the fact that dissolved oxygen can enhance the ECL intensity, a highly sensitive ECL sensor for the determination of dissolved oxygen was developed. This insight into the fundamental interactions between Mn²⁺ dopants and defects in NC host may open new opportunities for the design of novel ECL materials to promote their application potential in electrochemical analysis and imaging.

Supramolecular Organic Photocatalyst Containing a Cubanelike Water Cluster and Donor-Acceptor Stacks: Hydrogen Evolution and Dye Degradation under Visible Light

Supramolecular organic photocatalysts are scarcely explored for the generation of sustainable energy as well as for environmental remediation purposes. An organic photocatalyst, containing a cubanelike water cluster and donor-acceptor stacks, was efficiently developed through a supramolecular approach. The material exhibited remarkable photocatalytic hydrogen generation, in the absence of any cocatalyst, with excellent stability and recyclability. The photoactivity was further assessed through time-resolved photoluminescence and electrochemical impedance spectroscopy. The material also exhibited highly efficient sunlight-driven photocatalytic activity through the degradation of harmful organic dye methylene blue.

[CH3 NH3 ]4 Ga4 SbS9 S0.28 O0.72 H: A Three-Dimensionally Open-Framework Heterometallic Chalcogenidoantimonate Exhibiting Ni2+ Ion-Exchange Property

An open-framework chalcogenidoantimonate, namely, [CH₃ NH₃ ]₄ Ga₄ SbS₉ S_0.28 O_0.72 H (1), has been solvothermally synthesized and structurally characterized. Interestingly, 1 showed Ni²⁺ ion-exchange properties and wide pH resistance, with a maximum exchange capacity of 76.9 mg g^-1 . To the best of our knowledge, this is the first example of amine-directed three-dimensional (3D) heterometallic chalcogenidometalates for highly selective Ni²⁺ ion capture with a high distribution coefficient (K_d =1.65×10⁵  mL g^-1 ).

Surface Decorated Zn0.15Cd0.85S Nanoflowers with P25 for Enhanced Visible Light Driven Photocatalytic Degradation of Rh-B and Stability

Decoration of Zn0.15Cd0.85S nanoflowers with P25 for forming P25/Zn0.15Cd0.85S nanocomposite has been successfully synthesized with fine crystallinity by one-step low temperature hydrothermal method. Photocatalytic efficiency of the as-prepared P25/Zn0.15Cd0.85S for the degradation of Rh-B is evaluated under the visible light irradiation. The synthesized composite is completely characterized with XRD, FESEM, TEM, BET, and UV-vis DRS. TEM observations reveal that P25 is closely deposited on the Zn0.15Cd0.85S nanoflowers with maintaining its nanoflower morphology. The photocatalytic activity of the as-obtained photocatalyst shows that the P25/Zn0.15Cd0.85S exhibits very high catalytic activity for degradation of Rh-B under visible light irradiation due to an increasing of the active sites and enhancing the catalyst stability because of the minimum recombination of the photo-induced electrons and holes. Moreover, it is found that the nanocomposite retains its photocatalytic activity even after four cycles. In addition, to explain the mechanism of degradation, scavengers are used to confirm the reactive species. Photo-generated holes and ●OH play a significant role in the visible light of P25/Zn0.15Cd0.85S nanocomposite induced degradation system, but electrons play the most important role.

A series of new hybrid selenidostannates with metal complexes prepared in alkylol amines

A series of new hybrid selenidostannates were synthesized in alkylol amines, whose zinc selenidostannate with a photocurrent response represents the first example of the hybrid chalcogenidostannate incorporating rare tetrahedral metal complexes.

Design of two isoreticular Cd-biphenyltetracarboxylate frameworks for dye adsorption, separation and photocatalytic degradation

Two robust Cd-biphenyltetracarboxylate frameworks showing identical topological networks but different pore sizes exhibit not only high dye uptake capacity and selectivity, but also good photocatalytic degradation of RhB and MO.

Ethanol–water ambient precipitation of {111} facets exposed Ag3PO4 tetrahedra and its hybrid with graphene oxide for outstanding photoactivity and stability

The work presents the combinative merits of {111} facet effect and the GO hybrid of Ag₃PO₄ photocatalyst with dramatically improved photocatalytic activity and admirable circulation runs for water treatment.

New synthetic strategies to prepare metal–organic frameworks

This critical review summarizes the recent developments in the application of new synthetic strategies for preparing MOFs, including the ionothermal method, deep eutectic solvent usage, surfactant-thermal process, and mechanochemistry.