3D MoS₂ Composition Aerogels as Chemosensors and Adsorbents for Colorimetric Detection and High-Capacity Adsorption of Hg²⁺

Precise detection and effectively eliminating mercury pollution in aqueous solutions remains an onerous task for protecting the public health and environment. In this paper, porous MoS₂ composite aerogel-supported Au nanoparticles with strong mercury affinity have been fabricated to deal with this problem. Such composite aerogels are fabricated using graphene oxide (GO)-doped MoS₂ sheets as the feedstock by hydrothermal assembly and then the Au and Fe₃O₄ nanoparticles (NPs) embed between the GO-doped MoS₂ sheets through coordination. The resultant porous Au/Fe₃O₄/MoS₂CAs aerogel not only can sensitively detect mercury­(II) in aqueous solution by a colorimetric method with a low detection limit (3.279 nM) but also can exhibit a super mercury adsorption capacity (∼1527 mg g^–1) and fast desorption ability. After magnetic separation, the Hg²⁺ levels decreased from 10 ppm to 0.11 ppb within a few minutes, which is far below 2 ppb. In addition, Au/Fe₃O₄/MoS₂CAs could be successively recycled more than 10 times with high removal efficiency (>95%). The excellent performance of the composition aerogel profits from its 3D interconnected macroporous framework as well as strong coupling between Au nanoparticles and MoS₂ nanosheets, rendering it a potential detection and adsorbent material for mercury­(II) from contaminated water for environmental remediation

Copper-Catalyzed Aerobic Oxidative Dehydrogenative Formal [2 + 3] Cyclization of Glycine Esters with α‑Angelicalactone: Approach To Construct Polysubstituted Pyrrolidones

A novel and efficient copper-catalyzed aerobic oxidative dehydrogenative formal [2 + 3] cyclization of glycine derivatives with α-angelicalactone is described. A series of complex pyrrolidones were produced under mild and simple reaction conditions

Iron Catalyzed Dual-Oxidative Dehydrogenative (DOD) Tandem Annulation of Glycine Derivatives with Tetrahydrofurans

A novel iron-catalyzed dual-oxidative dehydrogenative (DOD) tandem annulation of glycine derivatives with tetrahydrofurans (THFs) for the synthesis of high value quinoline fused lactones has been developed. The reactions were performed under mild reaction conditions. And the use of cheap substrates (glycine derivatives and THF) and an even cheaper simple inorganic iron salt as the catalyst makes this protocol very attractive for potential synthetic applications

Hyper-Cross-linked Porous MoS₂–Cyclodextrin-Polymer Frameworks: Durable Removal of Aromatic Phenolic Micropollutant from Water

A reasonable and efficient strategy for the construction of hyper-cross-linked porous MoS₂–CD-polymer frameworks (MoS₂CDPFs) was demonstrated. Here, MoS₂ nanosheets (NSs) can be decorated with amino functionalized β-cyclodextrin, producing a nanoscale structural motif (MoS₂@CD) for the synthesis of MoS₂CDPFs. We demonstrated that CD polymer (CDP) as linker can be uniformly incorporated into the frameworks. Except for the pores created between MoS₂ NSs, polymer doping generates extra interspace between MoS₂ NSs and CD monomer. Interestingly, the resultant MoS₂CDPFs can rapidly sequester aromatic phenolic micropollutant bisphenol A (0.1 mM) from water with 93.2% adsorption capacity, which is higher than that of MoS₂, MoS₂@CD, and CDP. The intercalation between MoS₂ sheets with CDP imparts the frameworks durability in adsorption/desorption of aromatic phenolic micropollutants. Remarkably, the removal efficiency reduced only 3% after 10 regeneration–reuse cycles. These findings demonstrated that the porous MoS₂–CD-polymer-based frameworks are promising adsorbents for rapid, flow-through water remediation

Biomimetic and Cell-Mediated Mineralization of Hydroxyapatite by Carrageenan Functionalized Graphene Oxide

In bone tissue engineering, it is imperative to design multifunctional biomaterials that can induce and assemble bonelike apatite that is close to natural bone. In this study, graphene oxide (GO) was functionalized by carrageenan. The resulting GO-carrageenan (GO-Car) composite was further used as a substrate for biomimetic and cell-mediated mineralization of hydroxyapatite (HA). It was confirmed that carrageenan on the GO surface facilitated the nucleation of HA. The observation of the effect of the GO-Car on the adhesion, morphology, and proliferation of MC3T3-E1 cells was investigated. In vitro studies clearly show the effectiveness of GO-Car in promoting HA mineralization and cell differentiation. The results of this study suggested that the GO-Car hybrid will be a promising material for bone regeneration and implantation

Triple-Emitting Dumbbell Fluorescent Nanoprobe for Multicolor Detection and Imaging Applications

The combination of different fluorescent species into one nanostructure to develop fluorescent nanoparticles with multiple emission signatures by a single wavelength excitation has become a very popular research area in the field of multiplex bioanalysis, diagnostics, and multicolor imaging. However, these novel hybrids must be elaborately designed to ensure that the unique properties of each component are conveyed, i.e., fluorescent species and nanoparticles, and are maximized without serious interactions with each other. Herein, a first triple-fluorescence dumbbell nanoprobe with large Stokes shift based on incorporating fluorescein isothiocyanate (FITC) and lanthanide complexes onto Au–Fe₃O₄ NPs was synthesized. This hybrid displays well-resolved triple fluorescence emission, with FITC at 515 nm, Tb­(III) complex at 545 nm, and Eu­(III) complex at 616 nm under a single-excitation wavelength and is used for highly selective and sensitive colorimetric detection of Cu²⁺ with a detection limit of 30 nM. Under different Cu²⁺ concentrations, this hybrid exhibited distinguishable multiple colors under UV light, and the color could change in the presence of different concentrations of Cu²⁺. This sensor for ratio/multianalyte microscopic imaging of Cu²⁺ in HeLa cells and BHK cells was also demonstrated. Target molecules, such as folic acid, can be covalently attached to the fluorescent nanoparticle surface to serve as an effective probe for simultaneous multicolor imaging folate receptor-overexpressing HeLa cell lines in vitro

Phase Transformation Fabrication of a Cu₂S Nanoplate as an Efficient Catalyst for Water Oxidation with Glycine

The synthesis of semiconducting nanoplates (NPs) with defined crystal phase is of particular interest, especially their intriguing properties related to the size, shape, and crystal phase. Herein, a liquid-state transformation process from hexagonal-phase CuS NPs is employed to fabricate the cubic-phase Cu₂S NPs. The CuS NPs were converted into Cu₂S NPs but maintained the morphology. The Cu₂S NPs exhibit better oxygen evolution reaction (OER) activity than CuS NPs. Furthermore, the OER activity of Cu₂S NPs can be improved by the addition of a glycine (Gly) solution. The Cu₂S NPs with Gly in a phosphate buffer solution exhibit excellent OER activity and durability, which approaches that of the best known commercial Ir/C (20%) nanocatalyst. In this work, a good strategy for fabricating a noble-metal-free OER catalyst has been proposed, which could provide insight into developing new water oxidation catalysts with high activity

Efficient Hydrogen-Generation CuO/Co₃O₄ Heterojunction Nanofibers for Sensitive Detection of Cancer Cells by Portable Pressure Meter

Portable, low-cost, and quantitative detection of cancer cells at home and in the field has the potential to revolutionize medical diagnostics. We first report the design and synthesis of highly efficient folic-acid-conjugated hydrogen-generation tube-in-tube CuO/Co₃O₄ heterojunction nanofibers for highly sensitive and rapid recognition of cancer cells through a pressure signal under visible-light irradiation. The resultant nanofibers can dramatically enhance the hydrogen-generation activity of ammonia borane under visible-light irradiation. Such hydrogen-generation reaction can translate a molecular recognition event between folic acid and folate receptor to measurable pressure signal readout through a low-cost and portable pressure meter for target cancer cell detection. Limits of detection (LODs) down to 50 cells mL^–1 in only 15 min can be achieved. This result is superior to those of the other reported methods, indicating the superiority of the new pressure-based sensor in terms of sensitivity. The present study establishes the pressure meter as a useful tool for early clinical point-of-care cancer diagnosis

Mesoporous, Three-Dimensional Wood Membrane Decorated with Nanoparticles for Highly Efficient Water Treatment

Wood, an earth-abundant material, is widely used in our everyday life. With its mesoporous structure, natural wood is comprised of numerous long, partially aligned channels (lumens) as well as nanochannels that stretch along its growth direction. This wood mesostructure is suitable for a range of emerging applications, especially as a membrane/separation material. Here, we report a mesoporous, three-dimensional (3D) wood membrane decorated with palladium nanoparticles (Pd NPs/wood membrane) for efficient wastewater treatment. The 3D Pd NPs/wood membrane possesses the following advantages: (1) the uniformly distributed lignin within the wood mesostructure can effectively reduce Pd­(II) ions to Pd NPs; (2) cellulose, with its abundant hydroxyl groups, can immobilize Pd NPs; (3) the partially aligned mesoporous wood channels as well as their inner ingenious microstructures increase the likelihood of wastewater contacting Pd NPs decorating the wood surface; (4) the long, Pd NP-decorated channels facilitate bulk treatment as water flows through the entire mesoporous wood membrane. As a proof of concept, we demonstrated the use and efficiency of a Pd NPs/wood membrane to remove methylene blue (MB, C₁₆H₁₈N₃ClS) from a flowing aqueous solution. The turnover frequency of the Pd NPs/wood membrane, ∼2.02 mol_MB·mol_Pd^–1·min^–1, is much higher than the values reported in the literature. The water treatment rate of the 3D Pd NPs/wood membrane can reach 1 × 10⁵ L·m^–2·h^–1 with a high MB removal efficiency (>99.8%). The 3D mesoporous wood membrane with partially aligned channels exhibits promising results for wastewater treatment and is applicable for an even wider range of separation applications

<i>In Situ</i> High Temperature Synthesis of Single-Component Metallic Nanoparticles

Nanoparticles (NPs) dispersed within a conductive host are essential for a range of applications including electrochemical energy storage, catalysis, and energetic devices. However, manufacturing high quality NPs in an efficient manner remains a challenge, especially due to agglomeration during assembly processes. Here we report a rapid thermal shock method to <i>in situ</i> synthesize well-dispersed NPs on a conductive fiber matrix using metal precursor salts. The temperature of the carbon nanofibers (CNFs) coated with metal salts was ramped from room temperature to ∼2000 K in 5 ms, which corresponds to a rate of 400,000 K/s. Metal salts decompose rapidly at such high temperatures and nucleate into metallic nanoparticles during the rapid cooling step (cooling rate of ∼100,000 K/s). The high temperature duration plays a critical role in the size and distribution of the nanoparticles: the faster the process is, the smaller the nanoparticles are, and the narrower the size distribution is. We also demonstrated that the peak temperature of thermal shock can reach ∼3000 K, much higher than the decomposition temperature of many salts, which ensures the possibility of synthesizing various types of nanoparticles. This universal, <i>in situ</i>, high temperature thermal shock method offers considerable potential for the bulk synthesis of unagglomerated nanoparticles stabilized within a matrix