ChemNanoMat最新文献

Low-toxic multinary semiconductor quantum dots (QDs) showing a photoresponse in a wide wavelength range from visible to near-IR wavelength regions have been intensively investigated for fabricating efficient solar light conversion systems. Recently, AgBiS₂ QDs have attracted much attention for their application to improve the performance of QD solar cells because they have a large absorption coefficient in the visible and near-IR regions. In this report, we describe solution-phase preparation of ternary Ag−Bi−S QDs with different sizes and with different Ag/Bi ratios. The average size of resulting spherical Ag−Bi−S QDs was controllable from 2.7 to 8.1 nm by adjusting the reaction temperature from 373 to 473 K, while the Ag fraction of obtained QDs also increased with an increase in particle size. The absorption onset wavelength shifted from 850 to 1200 nm in the near-IR region as the particle size increased. AgBiS₂ QDs with an almost stoichiometric composition, obtained at reaction temperatures of 423 K and 473 K, contained no deep intragap states and exhibited a p-type semiconductor behavior, while QDs prepared at a reaction temperature of 393 K or lower had non-stoichiometric Ag-deficient compositions producing intragap defect states. Sensitized solar cells fabricated with stoichiometric AgBiS₂ QDs exhibited a photoresponse in visible and near-IR wavelength regions, the optimal PCE being 0.74% with AgBiS₂ QDs of 6.2 nm in diameter that were prepared at 423 K.

Ultrathin zirconium-based metal−organic framework (MOF) nanosheets, embedded with photochromic units, are expected to be highly efficient heterogeneous photocatalysts, thanks to their rich catalytic sites, short diffusion paths, and effective separation of photogenerated charge carriers. Herein, we reported the synthesis of novel Zr-MOF nanosheets (Zr-BTDB) through a solvothermal synthesis that integrates benzothiadiazole (BTz) as a photochromic moiety within the framework of MOF. The Zr-BTDB nanosheets processes a [Zr₁₂(μ₃-O)₈(μ₃-OH)₈(μ₂-OH)₆] cluster with hcp topology. Importantly, Zr-BTDB nanosheets exhibit excellent photocatalytic activity for the photooxidation of sulfides and amines at room temperature under blue light irradiation. Notably, these nanosheets maintain their photocatalytic activity and selectivity for up to five cycles without significant loss of activity and crystallinity. Systematical catalytic reactions revealed that the Zr-BTDB nanosheets enable the generation of singlet oxygen (¹O₂) and superoxide radical (O₂⋅⁻) under visible light irradiation, which is critical reactive oxygen species for the photooxidation of sulfides and benzylamines. Our work represents a straightforward route for the preparation of ultrathin, water stable, and visible-light-activated Zr-MOF nanosheets, offering new potentials for the selective photooxidation of sulfides and amines in an eco-friendly way.

Here, a series of nitrogen-doped carbon (NC) supported transition metal oxide catalysts were prepared by pyrolysis of chitosan-metal salt mixtures for the efficient synthesis 2,5-diformylfuran (DFF) from 5-hydroxymethylfurfural (HMF) and fructose. Among them, supported molybdenum-based species on nitrogen-doped carbon (Mo/NC) exhibited excellent activity and selectivity for selective oxidation of HMF to DFF. The presence of nitrogen species reduces the electron cloud density around the Mo species, thereby improving the catalytic activity. Moreover, the interaction between active MoO₂ species on the catalyst surface and NC ensured the stability of the catalyst, resulting in no significant loss of activity after four catalytic cycles. 99.5 % and 55.1 % yields of DFF with full conversion were obtained from HMF and fructose respectively over Mo/NC-chitosan-600 in DMSO under ambient air. In order to enhance DFF yield from fructose, sulfonate groups were introduced into Mo/NC-chitosan-600 catalyst, leading to the highest DFF yield of 70.2 %. In addition, this catalyst also allowed 10.0%, 22.9% and 33.3% DFF yields from glucose, sucrose and inulin, respectively.

Due to the complexity and diversity of infectious diseases, diagnosis based solely on symptoms and imaging manifestations is associated with a high rate of misdiagnosis, so it is particularly important to find reliable and accurate biomarkers. Four inflammatory biomarkers (CRP, IL-6, PCT and SAA) have different manifestations and roles in different infectious diseases and stages of infection, and the diagnosis and identification of infectious diseases can be realized through quantitative analysis of these four biomarkers simultaneously. In this study, we developed a colloidal gold nanoparticle (AuNP)-based multiplex LFA strip using eight highly-sensitive monoclonal antibodies that simultaneously detected CRP, IL-6, PCT and SAA in serum within 15 min. And quantitative analysis was achieved with a portable strip reader, the LODs were 2.5 μg/mL, 25.3 pg/mL 0.87 ng/mL and 8.8 μg/mL for CRP, IL-6, PCT and SAA, while detection ranges were 2.5–200 μg/mL, 25.3–8000 pg/mL 0.87–100 ng/mL and 8.8–200 μg/mL. Moreover, the quantitative colloidal gold assay correlated well with the results of a chemiluminescence immunoassay when testing clinical serum samples. Our developed method was reliable and accurate according to the recovery test results. Therefore, the strip can be used as an alternative method for the simultaneous monitoring of CRP, IL-6, PCT and SAA in serum samples.

Metal chelation, characterized by its precise interactions with diverse functional groups, assumes a pivotal role in providing structural stability and generating reactive centers within metalloproteins and metallopeptides. This, in turn, orchestrates the architecture and functionality of various biological processes in living organisms. In our biomimetic approach inspired by the intricacies of natural metallopeptides, we have purposefully designed pyridine-bis-tyrosine, a concise Metallopeptide Conjugate (sMPC). Demonstrating the capacity to form complexes with various bioactive metal ions, sMPC emerges as a promising tool for advancing our understanding of metal-binding proteins and catalyzing the development of cutting-edge biotechnological materials and technologies. Our investigations underscore the hierarchical self-assembly of these abridged conjugates into toroidal to vesicle nanostructures, influenced by concentration, and their susceptibility to spatial manipulation through metal ion coordination with functional groups. These biocompatible metal peptide complexes and their resultant nanomaterials present specific potential as exceptional therapeutic agents to address problems associated with metal ion deficiencies, offering a facile and low-cost alternative to traditional metallodrugs.

Silver selenide (Ag₂Se) is a promising thermoelectric material for near-room temperature applications. This study proposes a fast, simple, and cost-effective method for producing high thermoelectric performance bulk Ag₂Se. Ag₂Se powders were synthesized from Ag and Se powders via a one-hour wet ball milling process, followed by the fabrication of bulk pellets through low-temperature hot-pressing (130–250 °C) with a mere 0.5-hour holding time. Both Ag₂Se powders and bulk pellets exhibited a single phase of Ag₂Se with an orthorhombic structure. Moreover, uniform compositional distribution with the stoichiometric Ag : Se ratio was observed in all samples. Microstructural analysis revealed distinct grain boundaries in samples hot-pressed below 190 °C, transitioning to grain coalescence was at 190 °C and 250 °C. The thermoelectric and transport measurements demonstrated that the electrical conductivity decreased and the Seebeck coefficient increased with hot-pressing temperatures from 130 °C and 190 °C primarily due to reduced carrier concentrations. Thermal conductivity decreased with increasing hot-pressing temperatures up to 190 °C, attributed to the weak chemical bonding of Ag₂Se and the presence of defects. This combination resulted in a peak zT over 1.0 at 300 K, with an average zT close to 1.0 from 300 to 380 K. In comparison to other reported synthesis methods, the present approach offers significantly reduced processing time, simplicity, and cost-effectiveness. Despite lower temperatures and shorter processing times, the method produces Ag₂Se with zT values comparable to more intricate techniques. This fabrication route holds the potential for scalable mass production in the future.

Electrochemical hydrogen and acetate cogeneration from ethanol is a promising green hydrogen production technique with low hydrogen production energy consumption and high profitability. However, the poor catalytic stability of the anodic ethanol electro-oxidation reaction (EOR) retards the device application. We adopted a metal support interaction strategy to reinforce small-sized Au active sites using cuprous sulfide supports. The Au−Cu_2–xS/C showed a superior activity of 1055 mA mg_Au⁻¹ at 1.1 V vs. RHE and retained the high activity in the chronopotentiometric test, surpassing the Au/C catalyst. It was demonstrated that the Cu_2–xS support facilitated the formation of Au−OH and prevented the gold sites from aggregation, leading to high activity and stability for EOR. Finally, an electrochemical cogeneration electrolyzer assembled with the Au−Cu_2–xS/C anodic catalyst continuously ran for over 100 hours, suggesting the device‘s applicability.

With the growing demand for high-performance smart windows, the discover of a class of thermochromic materials with reversible cycling and rapid response characteristics has become urgent. In this work, we have uncovered a two-dimensional (2D) Ruddlesden-Popper (RP) phase halide perovskite, (PMA)₂MAPb₂I_7−xCl_x, where PMA=C₆H₅CH₂NH₃ and MA=CH₃NH₃, exhibiting exceptional reversible thermochromic properties. The 2D RP phase perovskite thin film features a low transition temperature (Tc=30 °C from the hydrated state to the hot state, along with a fast transition time of 40 s. Furthermore, the addition of 0.5 times excess MAI significantly enhances the visible light transmittance of the hydrated state. Characteristic hydration peaks in X-ray diffraction patterns and O−H bond absorption peaks Fourier-transform infrared spectra are observed in the thin film in its hydrated state, which disappear in the hot state, validating its reversible thermochromic properties. Additionally, a solar cell based on the thermochromic 2D RP phase thin film achieves a power conversion efficiency of 2.31 %, offering a promising solution for advanced smart window technologies.

Lead halide perovskites have been explored ardently in the past decade owing to their excellent photophysical properties. High-temperature cation exchange reactions have been employed to improve the stability and performance in perovskite lattice, but lacks control over size, shape, and stoichiometry. Herein, the solution phase interaction of cesium lead bromide (CsPbBr₃) nanocrystals with monovalent and bivalent copper ions, under ambient conditions is systematically investigated. The introduction of Cu¹⁺ explicitly initiates a one-dimensional growth with a distinct phase transition, that is from cubic to orthorhombic, while Cu²⁺ induces a partial exchange with Pb²⁺ with no phase change. DFT calculations suggest that Cu¹⁺ induces structural distortion via Cs¹⁺ substitution, altering the Goldschmidt tolerance factor and perovskite octahedral tilting, leading to the phase transition. Additionally, the oleic acid/amine ligands used to stabilize the nanocrystals, are preferentially etched away to form complexes with Cu¹⁺, initializing an oriented growth of the nanocubes to nanorods. A mechanistic investigation of the evolution of the nanorods gave insights on tuning the tolerance factor via room temperature modifications and cation exchanges in perovskites for anisotropy and morphology tuning. This effortlessly obtained perovskite nanorods with Cu¹⁺ could find effective applications in optoelectronics, and as novel photocatalysts.

Calcium ions (Ca²⁺) are essential for a myriad of physiological functions, including excitability, neurotransmitter release, gene transcription, cell proliferation, synaptic plasticity, and hormone secretion. Consequently, the detection of Ca²⁺ concentrations in water is of fundamental and practical significance. In this study, a novel method for the simple, visual, and rapid colorimetric detection of Ca²⁺ is introduced, leveraging the surface plasmon resonance (SPR) absorbances of gold nanoparticles (AuNPs) modified with 5-Pyrimidinylboronic acid (5-PBA). A color change from wine-red to gray-blue was observed with increasing concentrations of Ca²⁺, indicative of the agglomeration of AuNPs. This agglomeration displayed favorable anti-interference properties and selectivity. The limits of detection (LOD) were determined to be 0.08 mM by the unaided eye and 3.29 μM by UV-visible spectroscopy. Moreover, an excellent linear relationship (R²=0.9879) was maintained within the Ca²⁺ concentration range of 0.0 to 0.5 mM. These results suggest that AuNPs modified with 5-PBA are suitable for the quantitative determination of Ca²⁺. Subsequent testing on actual samples confirmed that this new method could be effectively applied to the monitoring of Ca²⁺ in water.