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1.
Proc Natl Acad Sci U S A ; 119(11): e2112109119, 2022 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-35263231

RESUMO

SignificanceDirect ethanol fuel cells are attracting growing attention as portable power sources due to their advantages such as higher mass-energy density than hydrogen and less toxicity than methanol. However, it is challenging to achieve the complete electrooxidation to generate 12 electrons per ethanol, resulting in a low fuel utilization efficiency. This manuscript reports the complete ethanol electrooxidation by engineering efficient catalysts via single-atom modification. The combined electrochemical measurements, in situ characterization, and density functional theory calculations unravel synergistic effects of single Rh atoms and Pt nanocubes and identify reaction pathways leading to the selective C-C bond cleavage to oxidize ethanol to CO2. This study provides a unique single-atom approach to tune the activity and selectivity toward complicated electrocatalytic reactions.

2.
Small ; 20(26): e2310112, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38221688

RESUMO

The development of effective oxygen evolution reaction (OER) and urea oxidation reaction (UOR) on heterostructure electrocatalysts with specific interfaces and characteristics provides a distinctive character. In this study, heterostructure nanocubes (NCs) comprising inner cobalt oxysulfide (CoOS) NCs and outer CoFe (CF) layered double hydroxide (LDH) are developed using a hydrothermal methodology. During the sulfidation process, the divalent sulfur ions (S2-) are released from the breakdown of the sulfur source and react with the Co-precursors on the surface leading to the transformation of CoOH nanorods into CoOS nanocubes. Further, X-ray photoelectron spectroscopy (XPS) and X-ray absorption spectroscopy (XAS) analyses reveal that the interactions at the interface of the CF@CoOS NCs significantly altered the electronic structure, thus enhancing the electrocatalytic performance. The optimal catalysts exhibited effective OER and UOR activities, the attained potentials are 1.51 and 1.36 V. This remarkable performance is attributable to the induction of electron transfer from the CoFe LDH to CoOS, which reduces the energy barrier of the intermediates for the OER and UOR. Furthermore, an alkaline water and urea two-cell electrolyzer assembled using CF@CoOS-2 NCs and Pt/C as the anode and cathode requires a cell voltage of 1.63 and 1.56 V along with a durability performance.

3.
Small ; 20(8): e2304999, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37821412

RESUMO

Rapid and precise acute myocardial infarction (AMI) diagnosis is essential for preventing patient death. In addition, the complementary roles of creatine kinase muscle brain (CK-MB) and cardiac troponin I (cTnI) cardiac biomarkers in the early and late stages of AMI demand their simultaneous detection, which is difficult to implement using conventional fluorescence and electrochemical technologies. Here, a nanotechnology-based one-stop immuno-surface-enhanced Raman scattering (SERS) detection platform is reported for multiple cardiac indicators for the rapid screening and progressive tracing of AMI events. Optimal SERS is achieved using optical property-based, excitation wavelength-optimized, and high-yield anisotropic plasmonic gold nanocubes. Optimal immunoassay reaction efficiencies are achieved by increasing immobilized antibodies. Multiple simultaneous detection strategies are implemented by incorporating two different Raman reports with narrow wavenumbers corresponding to two indicators and by establishing a computational SERS mapping process to accurately detect their concentrations, irrespective of multiple enzymes in the human serum. The SERS platform precisely estimated AMI onset and progressive timing in human serum and made rapid AMI identification feasible using a portable Raman spectrometer. This integrated platform is hypothesized to significantly contribute to emergency medicine and forensic science by providing timely treatment and observation.


Assuntos
Infarto do Miocárdio , Humanos , Creatina Quinase Forma MB , Infarto do Miocárdio/diagnóstico , Troponina I , Biomarcadores , Imunoensaio
4.
Small ; : e2404194, 2024 Aug 13.
Artigo em Inglês | MEDLINE | ID: mdl-39136198

RESUMO

Conversion and alloying-type transitional metal sulfides have attracted significant interests as anodes for Potassium-ion batteries (PIBs) and Sodium-ion batteries (SIBs) due to their high theoretical capacities and low cost. However, the poor conductivity, structural pulverization, and high-volume expansions greatly limit the performance. Herein, Co1-xS/ZnS hollow nanocube-like heterostructure decorated on reduced graphene oxide (Co1-xS/ZnS@rGO) composite is fabricated through convenient hydrothermal and post-heat vulcanization techniques. This unique composite can provide a more stable conductive network and shorten the diffusion length of ions, which exhibits a remarkable initial charge capacity of 638.5 mA h g-1 at 0.1 A g-1 for SIBs and 606 mA h g-1 at 0.1 A g-1 for PIBs, respectively; It is worth noting that the composite presents remarkable long stable cycle performance in PIBs, which initially delivered 274 mA h g-1 and sustained the charge capacity up to 245 mA h g-1 at high current density of 1 A g-1 after 2000 cycles. A series of in situ/ex situ detections and first principle calculations further validate the high potassium ions adsorption ability of Co1-xS/ZnS anode materials with high diffusion kinetics. This work will accelerate the fundamental construction of bimetallic sulfide hollow nanocubes heterostructure electrodes for energy storage applications.

5.
Small ; : e2402940, 2024 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-39004867

RESUMO

Iron oxide nanoparticles (IONPs) are widely used for biomedical applications due to their unique magnetic properties and biocompatibility. However, the controlled synthesis of IONPs with tunable particle sizes and crystallite/grain sizes to achieve desired magnetic functionalities across single-domain and multi-domain size ranges remains an important challenge. Here, a facile synthetic method is used to produce iron oxide nanospheres (IONSs) with controllable size and crystallinity for magnetic tunability. First, highly crystalline Fe3O4 IONSs (crystallite sizes above 24 nm) having an average diameter of 50 to 400 nm are synthesized with enhanced ferrimagnetic properties. The magnetic properties of these highly crystalline IONSs are comparable to those of their nanocube counterparts, which typically possess superior magnetic properties. Second, the crystallite size can be widely tuned from 37 to 10 nm while maintaining the overall particle diameter, thereby allowing precise manipulation from the ferrimagnetic to the superparamagnetic state. In addition, demonstrations of reaction scale-up and the proposed growth mechanism of the IONSs are presented. This study highlights the pivotal role of crystal size in controlling the magnetic properties of IONSs and offers a viable means to produce IONSs with magnetic properties desirable for wider applications in sensors, electronics, energy, environmental remediation, and biomedicine.

6.
Small ; : e2403319, 2024 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-39082204

RESUMO

Transition metal centers dispersed over nitrogen-doped carbon (M-NC) supports have been widely explored for electrocatalytic reactions; however, sparsely reported for electrochemical nitrogen reduction reaction (ENRR). Particularly, the single-atom catalysts (SACs) have shown reasonable ammonia yield rate and faradaic efficiency (FE), but their complex synthesis and low durability for long-term electrocatalysis runs restrict their use on a larger scale. Importantly, the catalytic active sites in metal nanostructured-based M-NC catalysts toward enhanced N2 adsorption and activation are still not clear as they are highly challenging to reveal. A few studies have predicted that the surface oxygen vacancies (Ovac) favor an enhanced ENRR performance. Herein, a strategy using tailored M-NC content and Ovac in a single catalyst for enhanced ammonia electrosynthesis is devised. A mesoporous bimetallic spinel oxide (CuFe2O4) supported over N-doped carbon (CuFe2O4@NC) derived from Prussian blue analog (PBA) via controlled pyrolysis possess is found to show boosted ENRR activity. Moreover, operando NH3 formation over the catalyst is observed using four electrode set up. This approach enables rapid evaluation ofelectrocatalytic efficacy and avoids false positive results. The rotating disc electrode results reveal that mass transport in acidic media and surface absorption in alkline media primarily regulate ENRR over CuFe2O4@NC electrocatalyst.

7.
Small ; 20(32): e2311840, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38470189

RESUMO

With the recently-booming hydrogen (H2) economy by green H2 as the energy carriers and the newly-emerged exhaled diagnosis by human organ-metabolized H2 as a biomarker, H2 sensing is simultaneously required with fast response, low detection limit, and tolerant stability against humidity, switching, and poisoning. Here, reliable H2 sensing has been developed by utilizing indium oxide nanocubes decorated with palladium and gold nanodots (Pd-Au NDs/In2O3 NCBs), which have been synthesized by combined hydrothermal reaction, annealing, and chemical bath deposition. As-prepared Pd-Au NDs/In2O3 NCBs are observed with surface-enriched NDs and nanopores. Beneficially, Pd-Au NDs/In2O3 NCBs show 300 ppb-low detection limit, 5 s-fast response to 500 ppm H2, 75%RH-high humidity tolerance, and 56 days-long stability at 280 °C. Further, Pd-Au NDs/In2O3 NCBs show excellent stability against switching sensing response, and are tolerant to H2S poisoning even being exposed to 10 ppm H2S at 280 °C. Such excellent H2 sensing may be attributed to the synergistic effect of the boosted Pd-Au NDs' spillover effect and interfacial electron transfer, increased adsorption sites over the porous NCBs' surface, and utilized Pd NDs' affinity with H2 and H2S. Practically, Pd-Au NDs/In2O3 NCBs are integrated into the H2 sensing device, which can reliably communicate with a smartphone.

8.
Chemistry ; 30(41): e202400833, 2024 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-38781011

RESUMO

It remains a challenge to accomplish colloidal synthesis of noble-metal nanocrystals marked by high quality, large quantity, and batch-to-batch consistency. Here we report a self-airtight setup for achieving robust, reproducible, and scalable production of Ag nanocubes with uniform and controlled sizes from 18 to 60 nm. Different from the conventional open-to-air setup, the self-airtight system makes it practical to stabilize the reaction condition by minimizing the loss of volatile reagents. The new setup also allows us to easily optimize the amount of O2 (from air) trapped in the system, ensuring burst nucleation of single-crystal seeds, followed by their slow growth into nanocubes. Most significantly, the new setup allows for the production of Ag nanocubes at gram quantities without sacrificing uniformity, corner/edge sharpness, controlled size, and high purity across different batches. The availability of high-quality Ag nanocubes in such a large quantity is anticipated to substantially boost their use in applications related to plasmonics, catalysis, and biomedicine.

9.
Nanotechnology ; 35(44)2024 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-39025084

RESUMO

Hydrothermally derived nanocubes of CeO2(10 nm) were explored as an efficient heterogeneous catalyst in the partial oxidation of aromatic alcohols to the corresponding aldehydes and aerobic oxidation ofp-nitrotoluene top-nitrobenzoic acid. The CeO2nanocatalyst was characterized by x-ray diffraction, transmission electron microscopy (TEM), energy dispersive spectroscopy, x-ray photoelectron spectroscopy, Brunauer-Emmett-Teller (BET) surface area analysis, Fourier transform infrared spectroscopy, thermal gravimetric analysis and ultraviolet-visible spectroscopy. TEM/high-resolution TEM micrographs reveal a morphology of mostly cubic nanostructures with exposed highly active {100} and {110} facets. The surface area of nanoceria was determined by BET analysis and found to be 33.8 m2g-1. To demonstrate the universality of the catalytic system, the selective oxidation of different substrates of benzylic alcohol and complete oxidation ofp-nitrotoluene was investigated under mild conditions. Absolute selectivity towards their respective aldehydes was found to be 99.50% (benzaldehyde), 90.18% (p-chlorobenzaldehyde), 99.71% (p-nitrobenzaldehyde), 98.10% (p-fluorobenzaldehyde), 94.66% (p-anisaldehyde) and 86.14% (cinnamaldehyde). Moreover, the catalytic oxidative transformation of nitrotoluene results in 100% conversion with 99.29% selectivity towards nitrobenzoic acid.

10.
Nanotechnology ; 35(38)2024 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-38906118

RESUMO

Herein, we demonstrate an optimization of dye-sensitized solar cells (DSSCs) through the development of single-layer and double-layer configurations. Focusing on the incorporation of brookite and anatase phases in varying ratios, the study aims to determine the optimal composition for enhanced photovoltaic performance. The active layer, composed of anatase- and brookite-TiO2nanoparticles, is further modified with a scattering layer comprising a mixture of anatase nanoparticles and brookite-TiO2in the form of nanocube or rice-like particles. The synthesis of TiO2nanostructures with various morphologies and phase compositions and their subsequent application in single-layer and double-layer DSSCs are presented. The results highlight the superior light-harvesting capabilities achieved through the strategic incorporation of brookite phase into the anatase phase, emphasizing the importance of optimizing the anatase: brookite ratio. The single-layer DSSCs exhibit a peak efficiency of 8.73%, achieved with a composition of 30 wt.% brookite and 70 wt.% anatase at a thickness of 15µms. In the context of double-layer DSSCs, the combined optimization of the active layer composition, scattering layer morphology, and utilization of anatase nanoparticles leads to a remarkable efficiency of 9.18%. These findings underscore the critical role of composition and morphology in enhancing the performance of DSSCs, showcasing the potential for brookite-based DSSCs in solar energy conversion.

11.
Environ Res ; 249: 118093, 2024 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-38237759

RESUMO

Plastic pollution has become a major environmental problem because it does not break down and poses risks to ecosystems and human health. This study focuses on the environmentally friendly synthesis of ZnO nanocubes using an extract from Ceropegia omissa H. Huber plant leaves. The primary goal is to investigate the viability of these nanocubes as visible-light photocatalysts for the degradation of bisphenol A (BPA). The synthesized ZnO nanocubes have a highly crystalline structure and a bandgap of 3.1 eV, making them suitable for effective visible-light photocatalysis. FTIR analysis, which demonstrates that the pertinent functional groups are present, demonstrates the chemical bonding and reducing processes that take place in the plant extract. The XPS method also studies zinc metals, oxygen valencies, and binding energies. Under visible light irradiation, ZnO nanocubes degrade BPA by 86% in 30 min. This plant-extract-based green synthesis method provides a long-term replacement for traditional procedures, and visible light photocatalysis has advantages over ultraviolet light. The study's results show that ZnO nanocubes may be good for the environment and can work well as visible light photocatalysts to break down organic pollutants. This adds to what is known about using nanoparticles to clean up the environment. As a result, this study highlights the potential of using environmentally friendly ZnO nanocubes as a long-lasting and efficient method of reducing organic pollutant contamination in aquatic environments.


Assuntos
Compostos Benzidrílicos , Luz , Fenóis , Extratos Vegetais , Poluentes Químicos da Água , Óxido de Zinco , Óxido de Zinco/química , Compostos Benzidrílicos/química , Fenóis/química , Fenóis/análise , Extratos Vegetais/química , Poluentes Químicos da Água/química , Catálise , Química Verde/métodos , Fotólise
12.
Environ Res ; 258: 119395, 2024 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-38909944

RESUMO

In this study, we report the development of a novel CuOx(3 wt%)/CoFe2O4 nanocubes (NCs) photocatalyst through simple co-precipitation and wet impregnation methods for the efficient photocatalytic degradation of triclosan (TCS) pollutants. Initially, rod-shaped bare CoFe2O4 was synthesized using a simple co-precipitation technique. Subsequently, CuOx was loaded in various percentages (1, 2, and 3 wt%) onto the surface of bare CoFe2O4 nanorods (NRs) via the wet impregnation method. The synthesized materials were systematically characterized to evaluate their composition, structural and electrical characteristics. The CuOx(3 wt%)/CoFe2O4 NCs photocatalyst exhibited superior photocatalytic degradation efficiency of TCS (89.9%) compared to bare CoFe2O4 NRs (62.1 %), CuOx(1 wt%)/CoFe2O4 (80.1 %), CuOx(2 wt%)/CoFe2O4 (87.0 %) under visible light (VL) irradiation (λ ≥ 420 nm), respectively. This enhanced performance was attributed to the improved separation effectiveness of photogenerated electron (e-) and hole (h+) in CuOx(3 wt%)/CoFe2O4 NCs. Furthermore, the optimized CuOx(3 wt%)/CoFe2O4 NCs exhibited strong stability and reusability in TCS degradation, as demonstrated by three successive cycles. Genetic screening on Caenorhabditis elegans showed that CuOx(3 wt%)/CoFe2O4 NCs reduced ROS-induced oxidative stress during TCS photocatalytic degradation. ROS levels decreased at 30, 60, and 120-min intervals during TCS degradation, accompanied by improved egg hatching rates. Additionally, expression levels of stress-responsible antioxidant proteins like SOD-3GFP and HSP-16.2GFP were significantly normalized. This study demonstrates the efficiency of CuOx(3 wt%)/CoFe2O4 NCs in degrading TCS pollutants, offers insights into toxicity dynamics, and recommends its use for future environmental remediation.


Assuntos
Cobalto , Cobre , Triclosan , Triclosan/química , Triclosan/toxicidade , Animais , Cobre/química , Catálise , Cobalto/química , Compostos Férricos/química , Compostos Férricos/toxicidade , Luz , Caenorhabditis elegans/efeitos dos fármacos , Caenorhabditis elegans/efeitos da radiação , Fotólise , Poluentes Químicos da Água/química , Poluentes Químicos da Água/toxicidade
13.
Mikrochim Acta ; 191(5): 284, 2024 04 23.
Artigo em Inglês | MEDLINE | ID: mdl-38652331

RESUMO

A dual-mode (colorimetric/fluorescence) nanoenzyme-linked immunosorbent assay (NLISA) was developed based on Au-Cu nanocubes generating Prussian blue nanoparticles (PBNPs). It is expected that this method can be used to detect the residues of sulfonamides in the field, and solve the problem of long analysis time and high cost of the traditional method. Sulfadimethoxine (SDM) was selected as the proof-of-concept target analyte. The Au-Cu nanocubes were linked to the aptamer by amide interaction, and the Au-Cu nanocubes, SDM and antibody were immobilized on a 96-well plate using the sandwich method. The assay generates PBNPs by oxidising the Cu shells on the Au-Cu nanocubes in the presence of hydrochloric acid, Fe3+ and K3[Fe (CN)6]. In this process, the copper shell undergoes oxidation to Cu2+ and subsequently Cu2 + further quenches the fluorescence of the carbon point. PBNPs exhibit peroxidase-like activity, oxidising 3,3',5,5'-tetramethylbenzidine (TMB) to OX-TMB in the presence of H2O2, which alters the colorimetric signal. The dual-mode signals are directly proportional to the sulfadimethoxine concentration within the range 10- 3~10- 7 mg/mL. The limit of detection (LOD) of the assay is 0.023 ng/mL and 0.071 ng/mL for the fluorescent signal and the colorimetric signal, respectively. Moreover, the assay was successfully applied to determine sulfadimethoxine in silver carp, shrimp, and lamb samples with satisfactory results.


Assuntos
Carbono , Colorimetria , Cobre , Ferrocianetos , Sulfadimetoxina , Ferrocianetos/química , Sulfadimetoxina/análise , Sulfadimetoxina/química , Cobre/química , Colorimetria/métodos , Carbono/química , Limite de Detecção , Ouro/química , Pontos Quânticos/química , Fluorometria/métodos , Nanopartículas Metálicas/química , Aptâmeros de Nucleotídeos/química , Nanopartículas/química , Animais , Ensaio de Imunoadsorção Enzimática/métodos
14.
Nano Lett ; 23(1): 58-65, 2023 01 11.
Artigo em Inglês | MEDLINE | ID: mdl-36584282

RESUMO

Immunoassays exploiting magnetization dynamics of magnetic nanoparticles are highly promising for mix-and-measure, quantitative, and point-of-care diagnostics. However, how single-core magnetic nanoparticles can be employed to reduce particle concentration and concomitantly maximize assay sensitivity is not fully understood. Here, we design monodisperse Néel and Brownian relaxing magnetic nanocubes (MNCs) of different sizes and compositions. We provide insights into how to decouple physical properties of these MNCs to achieve ultrahigh sensitivity. We find that tricomponent-based Zn0.06Co0.80Fe2.14O4 particles, with out-of-phase to initial magnetic susceptibility χ″/χ0 ratio of 0.47 out of 0.50 for magnetically blocked ideal particles, show the ultrahigh magnetic sensitivity by providing a rich magnetic particle spectroscopy (MPS) harmonics spectrum despite bearing lower saturation magnetization than dicomponent Zn0.1Fe2.9O4 having high saturation magnetization. The Zn0.06Co0.80Fe2.14O4 MNCs, coated with catechol-based poly(ethylene glycol) ligands, measured by our benchtop MPS show 3 orders of magnitude better particle LOD than that of commercial nanoparticles of comparable size.


Assuntos
Nanopartículas de Magnetita , Nanopartículas , Nanopartículas de Magnetita/química , Magnetismo , Campos Magnéticos , Fenômenos Físicos , Análise Espectral , Nanopartículas/química
15.
Angew Chem Int Ed Engl ; 63(14): e202317978, 2024 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-38357744

RESUMO

Nanoparticle (NP) characterization is essential because diverse shapes, sizes, and morphologies inevitably occur in as-synthesized NP mixtures, profoundly impacting their properties and applications. Currently, the only technique to concurrently determine these structural parameters is electron microscopy, but it is time-intensive and tedious. Here, we create a three-dimensional (3D) NP structural space to concurrently determine the purity, size, and shape of 1000 sets of as-synthesized Ag nanocubes mixtures containing interfering nanospheres and nanowires from their extinction spectra, attaining low predictive errors at 2.7-7.9 %. We first use plasmonically-driven feature enrichment to extract localized surface plasmon resonance attributes from spectra and establish a lasso regressor (LR) model to predict purity, size, and shape. Leveraging the learned LR, we artificially generate 425,592 augmented extinction spectra to overcome data scarcity and create a comprehensive NP structural space to bidirectionally predict extinction spectra from structural parameters with <4 % error. Our interpretable NP structural space further elucidates the two higher-order combined electric dipole, quadrupole, and magnetic dipole as the critical structural parameter predictors. By incorporating other NP shapes and mixtures' extinction spectra, we anticipate our approach, especially the data augmentation, can create a fully generalizable NP structural space to drive on-demand, autonomous synthesis-characterization platforms.

16.
Angew Chem Int Ed Engl ; : e202413774, 2024 Aug 13.
Artigo em Inglês | MEDLINE | ID: mdl-39136239

RESUMO

Developing sustainable energy solutions is critical for addressing the dual challenges of energy demand and environmental impact. In this study, a zinc-nitrate (Zn-NO3-) battery system was designed for the simultaneous production of ammonia (NH3) via the electrocatalytic NO3- reduction reaction (NO3RR) and electricity generation. Continuous wave CO2 laser irradiation yielded precisely controlled CoFe2O4@nitrogen-doped carbon (CoFe2O4@NC) hollow nanocubes from CoFe Prussian blue analogs (CoFe-PBA) as the integral electrocatalyst for NO3RR in 1.0-M KOH, achieving a remarkable NH3 production rate of 10.9 mgh-1cm-2 at -0.47 V versus RHE with exceptional stability. In-situ and ex-situ methods revealed that the CoFe2O4@NC surface transformed into high-valent Fe/CoOOH active-species, optimizing the adsorption energy of NO3RR (*NO2 and *NO species) intermediates. Furthermore, DFT calculations validated the possible NO3RR pathway on CoFe2O4@NC starting with NO3- conversion to *NO2 intermediates, followed by reduction to *NO. Subsequent protonation forms the *NH and *NH2 species, leading to NH3 formation via final protonation. The Zn-NO3- battery utilizing the CoFe2O4@NC cathode exhibits dual functionality by generating electricity with a stable open-circuit voltage of 1.38-V versus Zn/Zn2+ and producing NH3. This study inspires the simple design of low-cost catalysts for NO3RR-to-NH3 conversion and positions the Zn-NO3- battery as a promising technology for industrial applications.

17.
Small ; 19(24): e2207984, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-36896998

RESUMO

The spontaneous organization of two types of nanoparticles (NPs) with different shapes or properties into binary nanoparticle superlattices (BNSLs) with different configurations has recently attracted significant attention due to the coupling or synergistic effect of the two types of NPs, providing an efficient and general route for designing new functional materials and devices. Here, this work reports the co-assembly of polystyrene (PS) tethered anisotropic gold nanocubes (AuNCs@PS) and isotropic gold NPs (AuNPs@PS) via an emulsion-interface self-assembly strategy. The distributions and arrangements of the AuNCs and spherical AuNPs in the BNSLs can be precisely controlled by adjusting the effective size ratio (λeff ) of the effective diameter (deff ) of the embedded spherical AuNPs to the polymer gap size (L) between the neighboring AuNCs. λeff determines not only the change of the conformational entropy of the grafted polymer chains (∆Scon ) but also the mixing entropy (∆Smix ) of the two types of NPs. During the co-assembly process, ∆Smix tends to be as high as possible, and the -∆Scon tends to be as low as possible, leading to free energy minimization. As a result, well-defined BNSLs with controllable distributions of spherical and cubic NPs can be obtained by tuning λeff . This strategy can also be applied for other NPs with different shapes and atomic properties, thus largely enriching the BNSL library and enabling the fabrication of multifunctional BNSLs, which have potential applications in photothermal therapy, surface-enhanced Raman scattering, and catalysis.

18.
Environ Res ; 218: 114908, 2023 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-36442521

RESUMO

Trace amounts of semi-volatile organic compounds (SVOCs) of the two isothiazolinones of 2-methylisothiazol-3(2H)-one (MIT) and 2-octyl-4-isothiazolin-3-one (OIT) were detected both in the air and on glass surfaces. Equilibria of SVOCs between air and glass were examined by solid phase microextraction-gas chromatography/mass spectrometry (SPME-GC/MS). Surface to air distribution ratios of Ksa for MIT and OIT were determined to be 5.10 m and 281.74 m, respectively, suggesting more abundant MIT in the gas phase by a factor of ∼55. In addition, a facile method of silver nanocube (AgNC)-assisted surface-enhanced Raman scattering (SERS) has been developed for the rapid and sensitive detection of MIT and OIT on glass surfaces. According to MIT and OIT concentration-correlated SERS intensities of Raman peaks at ∼1585 cm-1 and ∼1125 cm-1, respectively. Their calibration curves have been obtained in the concentration ranges between 10-3 to 10-10 M and 10-3 to 10-11 M with their linearity of 0.9986 and 0.9989 for MIT and OIT, respectively. The limits of detection (LODs) of the two isothiazolinones were estimated at 10-10 M, and 10-11 M for MIT and OIT, respectively. Our results indicate that AgNC-assisted SERS spectra are a rapid and high-ultrasensitive method for the quantification of MIT and OIT in practical applications. The development of analytical methods and determination of the Ksa value obtained in this study can be applied to the prediction of the exposure to MIT and OIT from various chemical products and dynamic behaviors to assess human health risks in indoor environments.


Assuntos
Análise Espectral Raman , Compostos Orgânicos Voláteis , Humanos , Cromatografia Gasosa-Espectrometria de Massas/métodos , Microextração em Fase Sólida/métodos , Compostos Orgânicos Voláteis/análise , Limite de Detecção
19.
Environ Res ; 216(Pt 2): 114609, 2023 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-36272591

RESUMO

Excessive use of nitrofurantoin (NFT) and its residues can be harmful to the ecosystem, and to mitigate this, rapid and cost-effective detection of NFT in water bodies is needed. In this regard, we prepared a three-dimensional (3D) copper-zeolitic imidazole framework (Cu/ZIF-8)-derived bimetallic Cu5Zn8 alloy-embedded hollow porous carbon nanocubes (Cu5Zn8/HPCNC) for electrochemical detection of NFT. The resultant material is characterized using suitable spectrophotometry and voltammetry methods. Cu5Zn8/HPCNC is an effective electrocatalyst with high electrical conductivity and a fast electron transfer rate. It also has more catalytic active sites for improved electrochemical reduction of NFT. Fabricated Cu5Zn8/HPCNC-modified screen-printed electrode (SPE) for NFT reduction have a wide linear range with a low detection limit, and high sensitivity (15.343 µA µÐœ-1 cm-2), appreciable anti-interference ability with related nitro compounds, storage stability, reproducibility, and repeatability. Also, the practicability of Cu5Zn8/HPCNC/SPE can be successfully employed in NFT monitoring in water bodies (drinking water, pond water, river water, and tap water) with satisfactory recoveries.


Assuntos
Carbono , Poluentes Ambientais , Carbono/química , Técnicas Eletroquímicas , Porosidade , Ligas , Reprodutibilidade dos Testes , Ecossistema , Água , Zinco
20.
Nano Lett ; 22(13): 5570-5574, 2022 07 13.
Artigo em Inglês | MEDLINE | ID: mdl-35737851

RESUMO

The synthesis of Al nanocrystals (Al NCs) is a rapidly expanding field, but there are few strategies for size and morphology control. Here we introduce a dual catalyst approach for the synthesis of Al NCs to control both NC size and shape. By using one catalyst that nucleates growth more rapidly than a second catalyst whose ligands affect NC morphology during growth, one can obtain both size and shape control of the resulting Al NCs. The combination of the two catalysts (1) titanium isopropoxide (TIP), for rapid nucleation, and (2) Tebbe's reagent, for specific facet-promoting growth, yields {100}-faceted Al NCs with tunable diameters between 35 and 65 nm. This dual-catalyst strategy could dramatically expand the possible outcomes for Al NC growth, opening the door to new controlled morphologies and a deeper understanding of earth-abundant plasmonic nanocrystal synthesis.


Assuntos
Alumínio , Nanopartículas , Catálise , Ligantes , Nanopartículas/química
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