Seeded Growth Method Research Articles

Magnetoplasmonic Triblock Nanorods for Collective Linear Dichroism.

Polarized light detection is crucial for advancements in optical imaging, positioning, and obstacle avoidance systems. While optical nanomaterials sensitive to polarization are well-established, the ability to align these materials remains a significant challenge. Here, we introduce Au-Fe3O4-Au triblock nanorods as a novel solution. Synthesized via a space-confined seeded growth method, these magnetoplasmonic nanocomposites uniquely combine the strong polarization capabilities of Au nanorods with the magnetic alignment properties of Fe3O4 nanorods. This architecture results in exceptional collective linear dichroism, achieving a polarization ratio of approximately 14 at the device level. Our nanorods exhibit high detection sensitivity and laser damage resistance, positioning them as a promising platform for developing advanced optical devices.

Surface plasmon-induced various characteristics of Gold@Copper oxide nanostructures

The combined effect of metal incorporated semiconductor nanostructures (NSs) provides hybrid, proficient and more functional properties that are difficult to be provided by single component NSs in modern applications and industry. A facile seed growth method is adapted for the synthesis of gold coated by cuprous oxide (Au@Cu2O) core@shell NSs that are functionalized in their shell thickness and surface states. As synthesized Au@Cu2O core@shell cubic NSs contain single cubic Au as a core material with varying Cu2O shell thickness, confirmed by their microscopic analysis. Various spectroscopic analyses are is accomplished to confirm the chemical structure, crystallinity, oxidation state and binding energy of the concerned material over the core's surface. Optical absorption properties of core@shell NSs are greatly affected causing a shift in the surface plasmon resonance (SPR) peaks intensities with increase of the shell size. Photoluminescence (PL) spectra explain influence of Cu2O shell morphology over the emission characteristics that an increasing shell thickness caused an enhancement in PL emission peak along with red-shift of the peak. The elemental quantifying is done by XPS technique to provide a detailed surface reaction chemistry about oxidation states of copper. The charge-transfer at the metal-semiconductor interface results in highly intense and selective enhanced SERS signals via PL quenching, using Rhodamine-6G as the probe. The results provide useful information for preparation of various Au@Cu2O NSs for applications involving charge-transfer and SPR based interaction.

Enhancement of spectral responsivity of Ag: au nanoparticles by using seed-growth method

Enhancement of spectral responsivity of Ag: au nanoparticles by using seed-growth method

A sensitive gold nanoflower-based lateral flow assay coupled with gold staining technique for the detection of SARS-CoV-2 antigen.

Anenhanced lateral flow assay (LFA) is presentedfor rapid and highly sensitive detection of acute respiratory syndrome coronavirus-2 (SARS-CoV-2) antigens with gold nanoflowers (Au NFs) as signaling markers and gold enhancement to amplify the signal intensities. First, the effect of the morphology of gold nanomaterials on the sensitivity of LFA detection was investigated. The results showed that Au NFs prepared by the seed growth method showed a 5-fold higher detection sensitivity than gold nanoparticles (Au NPs) of the same particle size, which may benefit from the higher extinction coefficient and larger specific surface area of Au NFs. Under the optimized experimental conditions, the Au NFs-based LFA exhibited a detection limit (LOD) of 25 pg mL-1 for N protein using 135nm Au NFs as the signaling probes. Thesignal was further amplified by using a gold enhancement strategy, and the LOD for the detection of N protein achieved was5 pg mL-1. The established LFA also exhibited good repeatability and stability and showed applicability in the diagnosis of SARS-CoV-2 infection.

Gold Nanostructures for an Effective Bone Cancer Therapy: Numerical Simulation and Experimental Investigation

AbstractGold nanostructures play a crucial role in medical applications, harnessing size and shape‐dependent properties. A prominent area of research is cancer treatment through the photothermal approach. Here, numerical simulation is explored to study the impact of gold nanostructure size, shape, and laser parameters on spatiotemporal temperature patterns during photothermal therapy (PTT). Spherical, rod, star, bipyramid, and cubic nanostructures in small, medium, and large sizes underwent 150 s of laser irradiation. COMSOL software, incorporating bioheat physics, precisely gauged thermal variations. The structural characteristics notably influence the temperature profiles, with medium‐sized rod, star, and bipyramid gold nanoparticles exhibiting superior thermal properties. Experimental validation of simulations focuses on the optimal nanostructure, synthesizing through the seed growth method. Transmission electron microscopy, UV‐visible spectroscopy, and X‐ray diffraction analysis confirm its proposed characteristics. Results demonstrate a robust correlation between experimental and simulation parameters, affirming precision. Findings showcase photothermal properties in line with theoretical predictions. The aim of this study is to determine the optimal gold nanostructure for bone cancer treatment using PTT, addressing the challenges presented by the dense and resilient nature of bone tissue and deep tumor locations. By utilizing multi‐physical modeling and simulations facilitated by COMSOL software, a novel method for pre‐clinical estimation is introduced. This research provides insights into each nanoparticle‐based PTT process prior to ex vivo and in vivo studies, offering a comprehensive understanding of the interplay between nanostructure characteristics and PTT outcomes. The approach contributes to advancing the field of cancer treatment by enhancing the predictability and effectiveness of nanoparticle‐mediated PTT.

Synthesis and Optical Properties of CdSeTe/CdZnS/ZnS Core/Shell Nanorods.

Semiconductor nanorods (NRs) have great potential in optoelectronic devices for their unique linearly polarized luminescence which can break the external quantum efficiency limit of light-emitting diodes (LEDs) based on spherical quantum dots. Significant progress has been made for developing red, green, and blue light-emitting NRs. However, the synthesis of NRs emitting in the deep red region, which can be used for accurate red LED displays and promoting plant growth, is currently less explored. Here, we report the synthesis of deep red CdSeTe/CdZnS/ZnS dot-in-rod core/shell NRs via a seeded growth method, where the doping of Te in the CdSe core can extend the NR emission to the deep red region. The rod-shaped CdZnS shell is grown over CdSeTe seeds. By growing a ZnS passivation shell, the CdSeTe/CdZnS/ZnS NRs exhibit a photoluminescence emission peak at 670 nm, a full width at a half maximum of 61 nm and a photoluminescence quantum yield of 45%. The development of deep red NRs can greatly extend the applications of anisotropic nanocrystals.

Surface-Enhanced Raman Scattering for Probe Detection via Gold Nanorods and AuNRs@SiO2 Composites

In this paper, a self-assembly method was used to prepare gold nanorod composites, and a seed-growth method was used to adjust the amount of AgNO3 solution, enabling the preparation of gold nanorods with different aspect ratios. AuNRs@SiO2 nanocomposite particles were then prepared by using the Stöber method to coat the gold nanorod surface with silica. Transmission electron microscopy showed that the maximum aspect ratio of the gold nanorods was 4.53, which was achieved using 2 mL of 10 mM AgNO3 solution. The Raman-scattering intensity of the gold nanorods was studied using rhodamine 6G, thiram, melamine, and piroxicam, and detection limits of 10−8 M, 10−5 M, and 10−3 M were, respectively, achieved. As a substrate, these gold nanorods showed good repeatability and reproducibility, and trace detection was successfully achieved. A transmission electron microscopy analysis shows that the SiO2 shell became thicker with increasing tetraethyl orthosilicate addition. Using AuNRs@SiO2 as the base and R6G, thiram, and piroxicam as the probes, measurable detection limits of 10−9 M, 10−6 M, and 10−5 M were achieved, and this composite also showed excellent repeatability and reproducibility.

Innovative Synthesis of Adhesive-Assisted and Recyclable Fe3O4@PD-Ag Photomagnetic Nanocomposites as SERS probes for Ultrasensitive Thiram Detection on Fruit Peels

Surface-enhanced Raman spectroscopy (SERS) with enormous advantages has emerged as a powerful tool for both highly sensitive structural detection of analytes and various imaging applications. A notable advancement in the realm of multifunctional SERS substrates is the integration of magnetic nanoparticles endowed with magnetic manipulation capabilities and noble metal nanoparticles exhibiting plasmonic resonance properties. This synergistic combination offers substantial practical benefits for trace analysis across diverse fields. In this paper, a new paradigm of Fe3O4@PEI-DTC-Ag (Fe3O4@PD-Ag) photomagnetic nanocomposites based on magnetic Fe3O4 nanoparticles (NPs), the noble metal silver quantum dots (Ag QDs) and the adhesive layer polyethyleneimine dithiocarbamate (PEI-DTC) for convenient recycling and ultrasensitive SERS detection was developed by engineering hydrothermal and seed-growth methods. The SERS performance of the Fe3O4@PD-Ag substrates with varying amounts of Ag was evaluated by detecting 4-aminothiophenol (4-ATP). Among the tested samples, Fe3O4@PD-Ag-4 with a silver solution volume of 200 ml exhibited the optimal performance, showcasing an enhancement factor (EF) of 4.418 × 105. Moreover, the relative standard deviations (RSDs) were calculated to be less than 11.5 %, demonstrating the SERS substrates exhibit good uniformity and spectral reproducibility. Of note, the SERS substrate has demonstrated successful trace detection of thiram molecules, achieving a limit of detection (LOD) of up to 10-9 M. The intensity of SERS signals shows a linear correlation with the logarithm of thiram concentration, ranging from 10-4 to 10-9 M, thus providing compelling evidence for quantitative detection. Importantly, the Fe3O4@PD-Ag-4 SERS substrate also showcases outstanding performance for detecting thiram in real food, underscoring its significant potential for application in food safety monitoring.

A highly sensitive SERS optical fiber probe with PSS modified gold nano-bipyramids for trace detection of water contamination

The combination of surface-enhanced Raman scattering (SERS) and optical fiber has led to the development of SERS optical fiber probe, which demonstrates potential for real-time, in-situ, and flexible detection of water contamination. In this paper, a highly sensitive SERS optical fiber probe of gold nano-bipyramids (Au NBPs) was successfully developed for the first time. The Au NBPs were controllably synthesized by a heat-treated seed growth method. Surface modification of the Au NBPs was carried out by adding poly (sodium 4-styrenesulfonate) (PSS) instead of hexadecyl trimethyl ammonium bromide (CTAB), which changed the Zeta potential of the Au NBPs solution from positive to negative. The SERS properties of the Au NBPs can be significantly enhanced by optimizing the parameters of PSS content. The optical fiber end face was pretreated with silane coupling agent to introduce amino groups and exhibit positive charge. As a result, highly sensitive SERS optical fiber probes were prepared through electrostatic adsorption of the Au NBPs. The performance of the SERS optical fiber probe was evaluated. The crystalline violet (CV) limit concentration of 10−10 mol/L was detected by the optimized SERS optical fiber probe with satisfactory reproducibility and stability. Additionally, a limit concentration of 10−5 mol/L for thiram could also be detected by the SERS optical fiber probe. Finally, the SERS enhancement mechanism was further discussed. The finite element method was utilized to analyze the electromagnetic field distribution of Au NBPs, optical fibers, and SERS optical fiber probes, theoretically explaining the performance advantages of Au NBPs SERS optical fiber probes. Based on our results, the Au NBPs SERS optical fiber probe holds significant value for trace detection of water contamination and biomolecules.

Precision control of one-/two-dimensional assemblies for Poly(hexamethylene carbonate) block copolymers

The precision control of monodisperse nanomaterials with spatially distinct functionalities and properties is of particular interest in materials science. Creating biocompatible/biodegradable nanoparticles that can be colloidally stable in aqueous solution further paves the way to a broad range of bio-related applications. In present work, we demonstrate the precise fabrication of aliphatic polycarbonate based one-dimensional (1D) cylinders and 2D platelet micelles using living crystallization-driven self-assembly (CDSA) by seeded growth method. By synthesizing aliphatic polycarbonate core-forming block copolymers with different corona-to-core ratios, excellent control over dimensions of 1D cylinders and 2D platelets with good uniformity is achieved through effectively epitaxial growth in ethanol based on the mass ratios of unimer-to-seed. Meanwhile, segmented nanoparticles with spatially-defined chemistries can further be prepared by sequential seeded growth approach. Moreover, these 1D/2D nanostructures are colloidally stable in water, and further show excellently biocompatible property towards L929 cells. These promising properties of polycarbonate-based micelles enable to a wide application as cargo vehicles in bio-related fields.

Peroxidase-like activity and mechanism of gold nanoparticle-modified Ti3C2 MXenes for the construction of H2O2 and ampicillin colorimetric sensors.

Transition metal carbides modified by Au nanoparticles (Au/Ti3C2) were synthesized and developed as a colorimetric sensor for the determination of H2O2 and ampicillin. The surface electrical properties of Ti3C2 were changed, and Au nanoparticles (AuNPs) and gold growth solution were synthesized simultaneously. Au/Ti3C2 was obtained by seed growth method with AuNPs modified on the surface of transition metal carbides, nitrides or carbon-nitrides (Ti3C2 MXenes). The synthesized AuNPs and Ti3C2 had no peroxidase-like activity, but Au/Ti3C2 had. The peroxidase catalytic mechanism was due to electron transfer. The peroxidase activity of Au/Ti3C2 can be utilized for the determination of H2O2. The linear range of Au/Ti3C2 for H2O2 was 1-60 µM, and the detection limit was 0.12 µM (S/N = 3). A colometric sensor for ampicillin detection based on Au/Ti3C2 was further constructed since S in ampicillin formed an Au-S bond with Au/Ti3C2, leading to the weakening of its peroxidase-like property. The change of peroxidase-like property attenuated oxidation of TMB, and the ampicillin content was inversely proportional to the concentration of oxidized TMB, and the blue color of solution faded, which enabled the determination of ampicillin. The linear range for ampicillin was 0.005-0.5µg mL- 1, and the detection limit was 1.1 ng mL- 1 (S/N = 3). The sensor was applied to the detection of ampicillin in milk and human serum.

22% Record Efficiency in Nanorod Light-Emitting Diodes Achieved by Gradient Shells.

The external quantum efficiency (EQE) in light-emitting diodes (LEDs) based on isotropic quantum dots has approached the theoretical limit of close to 20%. Anisotropic nanorods can break this limit by taking advantage of their directional emission. However, the progress towards higher EQE by using CdSe/CdS nanorods (NRs) faces several challenges, primarily involving the low quantum yield and unbalanced charge injection in devices. Herein, the seeded growth method is modified and anisotropic nanorods are obtained with photoluminescence quantum yield up to 98% by coating a gradient alloyed CdZnSe shell around conventional spherical CdSe seeds. This intermediate alloyed CdZnSe shell combined with a subsequent rod-shaped CdZnS/ZnS shell can effectively suppress the electron delocalization in the typical CdSe/CdS nanorods due to their small conduction bandgap offset. Additionally, this alloyed shell can reduce the hole-injection barrier and create a larger barrier for electron injection, both effects promoting a balanced injection of electrons and holes in LEDs. Hence, LEDs are reached with high brightness (160341cd m-2) and high efficiency (EQE = 22%, current efficiency = 23.19cd A-1), which are the highest values to date for nanorod LEDs.

Increasing gold nanostars SERS response with silver shells: a surface-based seed-growth approach

A straightforward method to prepare surface enhanced Raman spectroscopy (SERS) chips containing a monolayer of silver coated gold nanostars (GNS@Ag) grafted on a glass surface is introduced. The synthetic approach is based on a seed growth method performed directly on surface, using GNS as seeds, and involving a green pathway, which only uses silver nitate, ascorbic acid and water, to grow the silver shell. The preparation was optimized to maximize signals obtaining a SERS response of one order of magnitude greater than that from the original GNS based chips, offering in the meantime good homogeneity and acceptable reproducibility. The proposed GNS@Ag SERS chips are able to detect pesticide thiram down to 20 ppb.

Implementation of the Seeded Growth Method in Fabricating 3D‐Printed Nanocomposite Contact Lenses for Selective Transmission

Gold nanoparticles (GNPs) are useful materials that may be used in a variety of applications such as colorblindness management, drug delivery, and bacteria reduction. When incorporated with optical lenses, GNPs cause an absorption dip in the transmission spectra of the lenses. Out of the aforementioned medical applications, colorblindness management is the most benefited from such spectra absorption as it can potentially block problematic wavelengths that patients suffer from and hence manage their colorblindness, where color vision deficiency (CVD), also known as colorblindness, is a congenital ocular disorder that has no current cure, and patients suffering from it rely on wearable aids that enhance their color perception by filtering out the certain wavelengths. Herein, customized gold nanocomposite contact lenses are fabricated via additive manufacturing to filter selective transmission wavelengths in the range of 540 and 560 nm. To allow selective filtering, seed‐mediated synthesis of GNPs through nine growth steps is utilized to vary the GNPs’ size and plasmonic filtering properties. Thereafter, three contact lenses are fabricated with different GNPs concentrations and particle sizes. In the results of the study, it is indicated that the fabricated lenses can block certain wavelengths selectively while acquiring properties similar to commercially available eyewear.

Fabrication of core-shell-like bimetallic SERS substrates with inter-coordination effect for catalysis of p-mercaptoaniline.

The present study discusses the core-shell structures of Au@Ag prepared by a seed-growth method. The morphology and composition of Au@Ag nanoparticles were analyzed, indicating that they were successfully prepared. By studying the surface-enhanced Raman scattering spectra (SERS) of p-mercaptoaniline (PATP) molecules adsorbed on Au@Ag substrates, it was found that PATP molecules could be oxidized to form p-mercaptoazobenzene (DMAB) on Au@Ag substrates, indicating that the gold-silver bimetallic nanomaterials could catalyze the PATP molecules with excellent enhancement effect and stability. In order to further study the enhancement effect of the Au@Ag substrate, the electric field strength of Au nanoparticles and Au@Ag nanoparticles was simulated by using the finite difference time domain (FDTD) method, which showed that the SERS enhancement effect of Au@Ag nanoparticles was more significant as well as consistent with the experimental results. This work provides a reference for further preparation of efficient and stable bimetallic SERS substrates.

Effect of Aspect Ratio of a Gold-Nanorod-Modified Screen-Printed Carbon Electrode for Carbaryl Detection in Three Different Samples of Vegetables.

In this study, three different sizes of gold nanorods (AuNRs) were synthesized using the seed-growth method by adding various volumes of AgNO3 as 400, 600, and 800 μL into the growth solution of gold nanoparticles. Three different sizes of AuNRs were then characterized using UV-vis spectroscopy, high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED) patterns, and atomic force microscopy (AFM) to investigate the surface morphology, topography, and aspect ratios of each synthesized AuNR. The aspect ratios from the histogram of size distributions of three AuNRs as 2.21, 2.53, and 2.85 can be calculated corresponding to the addition of AgNO3 volumes of 400, 600, and 800 μL. Moreover, each AuNR in three different aspect ratios was drop-cast onto the surface of a commercial screen-printed carbon electrode (SPCE) to obtain three different SPCE-modified AuNRs (SPCE-A400, SPCE-A600, and SPCE-A800, respectively). All SPCE-modified AuNRs were then evaluated for their electrochemical behavior using cyclic voltammetry and electrochemical impedance spectroscopy (EIS) techniques and the highest electrochemical performance was shown as the order of magnitude of SPCE-A400 > SPCE-A600/SPCE-A800. The reason for the highest electrocatalytic activity of SPCE-A400 might be due to the smallest particle size and uniform distribution of AuNRs ∼ 2.2, which enhanced the charge transfer, thus providing the highest electroactive surface area (0.6685 cm2) compared to other electrodes. These results also confirm that the sensing mechanism for all SPCE-modified AuNRs is controlled by diffusion phenomena. In addition, the optimum pH was obtained as 4 for carbaryl detection for all SPCE-modified AuNRs with the highest current shown by SPCE-A400. Furthermore, SPCE-A400 has the highest fundamental parameters (surface coverage, catalytic rate constant, electron transfer rate constant, and adsorption capacity) for carbaryl detection, which were investigated using cyclic voltammetry and chronoamperometric techniques. The electroanalytical performances of all SPCE-modified AuNRs for carbaryl detection were also investigated with SPCE-A400 displaying the best performance among other electrodes in terms of its linearity (0.2-100 μM), limit of detection (LOD) ∼ 0.07 μM, and limit of quantification (LOQ) ∼ 0.2 μM. All SPCE-modified AuNRs were also subsequently evaluated for their stability, reproducibility, and selectivity in the presence of interfering species such as NaNO2, NH4NO3, Zn(CH3CO2)2, FeSO4, diazinon, and glucose and show reliable results as depicted from %RSD values less than 3%. At last, all SPCE-modified AuNRs have been employed for carbaryl detection using a standard addition technique in three different samples of vegetables (cabbage, cucumber, and Chinese cabbage) with its results (%recovery ≈ 100%) within the acceptable analytical range. In conclusion, this work demonstrates the great potential of a disposable device based on an AuNR-modified SPCE for rapid detection and high sensitivity in monitoring the concentration of carbaryl as a residual pesticide in vegetable samples.

Using anti-PD-L1 antibody conjugated gold nanoshelled poly (Lactic-co-glycolic acid) nanocapsules loaded with doxorubicin: A theranostic agent for ultrasound imaging and photothermal/chemo combination therapy of triple negative breast cancer.

Triple negative breast cancer (TNBC) has the worst prognosis of all breast cancers, and it is difficult to progress through traditional chemotherapy. Therefore, the treatment of TNBC urgently requires agents with effective diagnostic and therapeutic capabilities. In this study, we obtained programmed death-ligand 1 (PD-L1) antibody conjugated gold nanoshelled poly(lactic-co-glycolic acid) (PLGA) nanocapsules (NCs) encapsulating doxorubicin (DOX) (DOX@PLGA@Au-PD-L1 NCs). PLGA NCs encapsulating DOX were prepared by a modified single-emulsion oil-in-water (O/W) solvent evaporation method, and gold nanoshells were formed on the surface by gold seed growth method, which were coupled with PD-L1 antibodies by carbodiimide method. The fabricated DOX@PLGA@Au-PD-L1 NCs exhibited promising contrast enhancement in vitro ultrasound imaging. Furthermore, DOX encapsulated in NCs displayed good pH-responsive and photo-triggered drug release properties. After irradiating 200 μg/mL NCs solution with a laser for 10 min, the solution temperature increased by nearly 23°C, indicating that the NCs had good photothermal conversion ability. The targeting experiments confirmed that the NCs had specific target binding ability to TNBC cells overexpressing PD-L1 molecules. Cell experiments exhibited that the agent significantly reduced the survival rate of TNBC cells through photochemotherapy combination therapy. As a multifunctional diagnostic agent, DOX@PLGA@Au-PD-L1 NCs could be used for ultrasound targeted contrast imaging and photochemotherapy combination therapy of TNBC cells, providing a promising idea for early diagnosis and treatment of TNBC.

Highly sensitive metal-enhanced fluorescence platform based on high-quality CdSe/ZnS quantum dots and gold nanodendrites

Fluorescence immunosensors are highly demanded for diagnosing, monitoring and pathogenesis of diseases. Yet, the low sensitivity due to the weak fluorescence intensity of commonly employed fluorescent materials is the major obstacle towards early accurate diagnosis of targeted diseases. Herein, we resolve this issue by designing a highly sensitive fluorescence platform via employing colloidal quantum dots (QDs)-metal nanoparticles hybrid system. The QDs exhibit high chemical, thermal, and optical stability, excellent biocompatibility with ultrahigh quantum yield (∼88 %). They exhibit a core/shell architecture with type-I band alignment. The gold nanodendrites (AuNDs) synthesized via seed growth method with controllable sizes exhibit anisotropic shape, which maximizes the impacts of local surface plasmon resonance to amplify the fluorescence performance of colloidal QDs. Utilizing the designed platform and taking C-reactive protein as a testcase, we achieve ∼17-fold sensitivity improvement compared with metal nanoparticles free sensing platform, and a wide detection range between 0.25 ng/mL and 1000 ng/mL, and a low detection limit of 0.056 ng/mL. The designed sensing platform has been extended for the detection of real blood and tissue samples, and competing results have been delivered compared with the prevailing detecting technique. The present work reports a novel route of designing biological sensing platform through fluorescence amplification, which holds great potential for highly sensitive and throughput detection in clinical applications, and is widely applicable for highly sensitive detection of other biomarkers in biomedical applications.

Unexpected high performance of ZIF-8 membranes for 1,3-butadiene purification

The purification of 1,3-butadiene from C4 hydrocarbon mixtures currently relies on energy-intensive extractive distillation. In this study, we employed ZIF membranes for this challenging separation for the first time, unveiling their superior capability in isolating 1,3-butadiene from other C4 hydrocarbons with similar sizes, including 1-butene, isobutene, and n-butane. This strong sieving effect was evident from two types of ZIF-8 membranes: one with low crystallinity fabricated via the all-vapor-phase ligand-induced permselectivation (LIPS) method and another with high crystallinity synthesized through the seeded growth method. The gas permeances decreased with increasing kinetic diameters, following the order of 1,3-butadiene (4.31 Å) > 1-butene (4.46 Å) > n-butane (4.687 Å) > isobutene (4.84 Å). The LIPS-ZIF-8 membrane exhibited a high 1,3-butadiene permeance of approximately 1.43 × 10−7 mol/m2 s Pa (∼430 GPU) and ideal separation factors of 18, 56, and 134 for 1,3-butadiene over 1-butene, n-butane, and isobutene, respectively. In separating four-component C4 mixtures, these membranes could enrich 1,3-butadiene content from 50% in the feed to 96–98% in the permeate through a single separation step. This unprecedented performance is attributed to differences in C4 diffusivities that span several orders of magnitude.

Piezo-photocatalysis for efficient charge separation to promote CO2 photoreduction in nanoclusters

The substantial emissions of CO2 greenhouse gases have resulted in severe environmental problems, and research on the implementation of semiconductor materials to minimize CO2 is currently a highly discussed subject. Effective separation of interface charges is a major challenge for efficient piezo-photocatalytic systems. Meanwhile, the ultrasmall-sized metal nanoclusters can shorten the distance of electron transport. Herein, we synthesized Au25(p-MBA)18 nanoclusters (Au25 NCs) modified red graphitic carbon nitride (RCN) nanocatalysts with highly exposed Au active sites by in-situ seed growth method. The loading of Au25 NCs on the RCN surface provides more active sites and creates a long-range ordered electric field. It allows for the direct utilization of the piezoelectric field to separate photogenerated carriers during photo-piezoelectric excitation. Based on the above advantages, the rate of CO2 reduction to CO over Au25 NCs/RCN (111.95 μmol g−1 h−1) was more than triple compared to that of pristine RCN. This paper has positive implication for further application of metal clusters loaded semiconductor for piezo-photocatalytic CO2 reduction.