Metal Nanoparticles Research Articles

Flow cytometric analysis of the murine placenta to evaluate nanoparticle platforms during pregnancy

Clinically approved therapeutics for obstetric conditions are extremely limited, with over 80% of drugs lacking appropriate labeling information for pregnant individuals. The pathology for many of these obstetric conditions can be linked to the placenta, necessitating the development of therapeutic platforms for selective drug delivery to the placenta. When evaluating therapeutics for placental delivery, literature has focused on ex vivo delivery to human placental cells and tissue, which can be difficult to source for non-clinical researchers. Evaluating in vivo drug delivery to the placenta using small animal models can be more accessible than using human tissue, but robust, quantitative methods to characterize delivery remain poorly established. Here, we report a flow cytometric method to evaluate in vivo drug delivery to the murine placenta. Specifically, we describe techniques to identify key cell types in the murine placenta — trophoblasts, endothelial cells, and immune cells — via flow cytometric analysis. While we have employed this method to detect lipid nanoparticle-mediated nucleic acid delivery, this approach can extend to a variety of drug carriers (e.g., liposomes, exosomes, polymeric and metallic nanoparticles) and payloads (e.g., small molecules, proteins, other nucleic acids). Similarly, we describe the application of this method toward immunophenotypic analysis to assess changes in the placental immune environment during disease or in response to a therapeutic. Together, the techniques reported herein aim to broaden the accessibility of placental research in an effort to encourage collaboration between physician-scientists, engineers, placental biologists, and clinicians for developing novel therapeutics to treat placental conditions during pregnancy.

Synthesis and electrochemical characteristics of metal nanoparticles decorated composite anode made of domestic alloy, used in lithium ion batteries

In this work, appropriate material selection and process design enable the succesful production of high energy density electrode active material in the form of XAZ (where X, A and Z stand for electrochemically active, electrochemically inactive and carbon materials, respectively). Herein, the precipitates rich in iron and chromium are extracted selectively from a local ferrochromium alloy utilizing hydrometallurgy procedures. The precipitates are then exposed to separate calcination to get iron-rich and chromium-rich oxides seperately. In the end, a composite (XAZ) is fabricated under the mild synthesis conditions by combining these oxides with activated carbon and aluminum powder in a planetary ball mill. The composite's morphological, structural, and chemical properties are all optimized. The galvanostatic test results clearly demonstrate that the powder made of XAZ composite with embedded metal nanoparticles delivers 798 mAh g-1 after 100th cycle under a current load of 50 mA g-1 and high capacity (600 mAh g−1) over 300 cycles with an exceptional rate performance. It is anticipated that this research will create novel opportunities for producing high-value electrode active materials from accessible, low-cost raw ingredients.

Enhancement of photocatalytic activity by thermal annealing of Au, Ag, and Cu implanted TiN thin films

The paper presents an investigation on the optoelectronic and photocatalytic properties of titanium-nitride (TiN) thin films, modified through the introduction of metal ions (Au, Ag, and Cu) during implantation, followed by thermal annealing. Employing high-resolution microscopic and spectroscopic techniques, we examined the microstructural and compositional features of the films in detail. The films exhibited a crystalline structure with distinct columnar patterns, attributed to defect release and recovery during annealing. Furthermore, metal nanoparticles were detected in samples implanted with gold and silver ions, indicating coalescence processes, while no such particles were observed in the case of Cu ions. Post-implantation annealing also led to surface oxidation and the formation of anatase TiO2, with a coexistence of TiO2, TiN, metallic Au and Ag, and CuO phases in subsurface regions. Comparative optical measurements revealed significant changes in photoluminescence efficiency and photocatalytic response of modified TiN. All implanted samples showed reduced photoluminescence intensity compared to pristine titanium-nitride, with the Au-implanted film exhibiting the most significant decrease, due to the presence of surface Au nanoparticles, thus resulting in the slower electron-hole recombination rates and enhanced photocatalytic activity.

Theranostic scope of monometallic selenium and titanium dioxide nanoparticles in biomedicine: A review.

The nanoparticles (NPs) of metals and metal oxides constitute significant components of technology in terms of monometallic NPs (MNPs). Over the last decade, the most fascinating and in-depth uses of NPs have been found in the biomedical field, which has demonstrated the therapeutic potential of these particles. Significant strides have been made in the application of nanotechnology across various industries, including biomedical sciences. In biomedicine, two of the most important applications of NPs are in the diagnosis and treatment of disease. Given their ability to deliver specific drugs, these next-generation NPs provide safe and effective pharmacotherapies for a wide range of disorders. Selenium nanoparticles (SeNPs) and titanium dioxide (TiO2) NPs offer potential treatments for various applications, including hair care and cancer treatment. SeNPs help with abiotic stress, plant disease, and growth, while TiO2 NPs enhance bio-imaging and drug delivery. This comprehensive review focuses on MNPs like Se (metal-based) and TiO2 (metal-oxide based). It covers their synthesis methods, nanoscale physicochemical properties, and the definition of specific industrial applications in various fields of applied nanotechnology, including biomedicine.

Fast Reduction of 4-Nitrophenol and Photoelectrochemical Hydrogen Production by Self-Reduced Bi/Ti3C2Tx/Bi2S3 Nanocomposite: A Combined Experimental and Theoretical Study.

The distinctive properties of 2D MXenes have garnered significant interest across various fields, including wastewater treatment and photo/electro-catalysis. The integration of inexpensive semiconductor nanostructures with 2D MXenes offers a promising strategy for applications such as wastewater treatment and photoelectrochemical hydrogen production. In this study, we employed an in situ hydrothermal method to immobilize 1D Bi2S3 nanorods and self-reduced metallic bismuth nanoparticles (Bi NPs) onto Ti3C2Tx MXene nanosheets, resulting in the formation of a Bi/Bi2S3/Ti3C2Tx (0D/1D/2D) composite catalyst, which demonstrates an outstanding efficacy in both the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) and photoelectrochemical hydrogen production. Remarkably, a 4-NP reduction efficiency of 100% was achieved only in 4 min with a reduction rate of 1.14 min-1, which is outstanding, and it is ∼3.8 times faster than pristine Bi2S3 nanorods (0.3 min-1). Furthermore, the photoelectrochemical assessment reveals that the Bi/Bi2S3/Ti3C2Tx catalyst displays remarkable hydrogen evolution reaction (HER) efficiency in an alkaline electrolyte. It exhibits a significantly lower overpotential and Tafel slope of 73 mV and 84 mV/dec, respectively, compared to pristine Bi2S3 nanorods, which are found to be 129 mV and 145 mV/dec under light illumination. The superior reduction performance of 4-NP and charge transfer mechanism is further investigated through density functional theory (DFT) calculations, alongside validation using various microscopic and spectroscopic techniques. Interestingly, the DFT analysis revealed modifications in the partial density of states of Bi2S3 within the band gap region due to the successful anchoring of Ti3C2Tx nanosheets and metallic Bi NPs, facilitating efficient charge transport and separation across the local junctions. Ultraviolet photoelectron spectroscopy provided insights into band alignment and interfacial charge transfer across the Bi/Bi2S3/Ti3C2Tx junction on a microscopic scale. This work is significant for the development of MXene-based hybrid catalysts, and it provides a deeper understanding of the reduction mechanism of organic pollutants and superior charge transport in the hybrid system for photoelectrochemical hydrogen production.

Anchoring nickel sites on ceria-coated silica to enhance the catalytic stability for the vapor phase levulinic acid hydrogenation

The preparation of the binary metal NiCe-based catalysts involved a 2-step protocol, the ceria was first coated on SiO2 which was then utilized to disperse Ni nanoparticles. Various techniques including N2 adsorption/desorption, ICP-OES, XRD, HRTEM, XPS, H2-chemisorption, H2-TPR, NH3-TPD, and TG etc. were performed to study the microstructure, redox, acid property and deactivation. The results revealed that CeO2 and metallic Ni were well dispersed on the support surface, the synergistic effect between the two metal species was conserved well. The content of CeO2 had considerable effects on redox and metallic properties rather than the acidic property. The dispersion of metallic Ni played a dominant role in promoting the catalytic activity. The levulinic acid conversion attained 84.0 % with a γ-valerolactone selectivity of 98.8 % on Ni/SiO2@2CeO2 sample with the highest dispersion of 9.8 %. The amorphous CeO2 suppressed the sintering of metallic Ni nanoparticles and improved the coke resistance, leading to better catalytic activity within 20 h time on stream.

Strong interaction between promoter and metal in Pd-Ba/TiO2 catalysts for formaldehyde oxidation

As our previous works found, alkali metals have a common promotion effect on supported noble metals catalysts for formaldehyde (HCHO) oxidation. As second-group elements, alkaline earth metals (AEMs) are neighbors to the first-group elements and share some properties in common. However, detailed investigations into the specific mechanisms underlying AEMs’ effects on HCHO oxidation remain limited. In this study, we found that Ba addition showed a similar promotion effect on HCHO oxidation for Pd/TiO2. Ba species stabilized Pd groups, improved the dispersion, and even caused a large number of monatomic-like Pd sites to appear, which may be attributed to the electronic interaction between promoter and metal (EIPM) between Ba and Pd. Besides, AEM loading had the important effect of increasing the electron density of metallic Pd nanoparticles, which further improved the ability for O2 activation and so enhanced the mobility of chemisorbed oxygen on the catalyst surface. For Pd/TiO2, the HCHO oxidation path is mainly HCHO→HCOOH→HCOO→H2O+CO2. By contrast, for Pd-Ba/TiO2, with more surface-active species, the formate intermediate was more likely to be directly oxidized into H2O and CO2, which is a more effective reaction pathway. The details of the EIPM between Pd and Ba were investigated by GPAW (DFT calculation module) in ASE (Atomic Simulation Environment). The AEM Ba acted as an electron donor and could interact with Pd d orbital electrons through BaO sp orbital electrons. Ba species were highly dispersed on the carrier due to the Ba-Ti interaction. Ba species dispersed over large areas stabilized the Pd particles and donated electrons to Pd. Therefore, adding an AEM is an efficacious strategy to improve the performance of the catalytic oxidation of HCHO.

Electrochemical remediation of methyl orange over reusable biochar ferrite coated photocatalytic plates

Biochar (BC) obtained from biomass pyrolysis holds immense potential for environmental remediation. The efficiency of BC can further be enhanced by incorporating metal nanoparticles (NPs) in the porous carbon matrix. In the present work nanocomposites (NCs) were prepared by the addition of ferrite nanoparticles (FNPs) into an oxidized BC matrix to create BC /Fe3O4 (BCF). This process improves BC stability, electron transfer, conductivity, and photocatalytic ability for dye degradation. Microstructure and functional group analysis of BCF was performed by SEM, XRD, and FTIR showing intercalation of FNPs with surface functionalities of oxidized BC matrix. The B-H curve of FNPs and BCF reveals super paramagnetic behavior with saturation magnetization (Ms, emu/g) of 67.36 and 20.01 respectively. BET surface area analysis shows surface area (m2/gm) 45.81 and 44.19 for oxidized BC and BCF respectively, that attributed to partial blocking of porous carbon matrix by FNPs. UV-DRS supports the semiconducting behavior of BCF with a significantly reduced band gap (eV) of 2.95 over pristine BC (4.76). BCF-coated photocatalytic plates (PCPs) were developed and utilized for the remediation of methyl orange (MeO) in water samples. Degradation of MeO was investigated over time by electrochemical methods. The square wave voltammetric method showed the limit of detection and quantification of 0.09 ppm and 0.28 ppm respectively for MeO over a glassy carbon electrode in 0.1 M acetate buffer. BCF-derived PCPs rendered ∼99 % degradation efficiency against MeO (50 mgL−1) under UV radiation over 240 min. Developed PCPs demonstrate reusability up to 5 cycles without any further purification step and offer efficient degradation of MeO making them suitable for the treatment of water polluted with dyes.

Marine microbial exopolysaccharide route synthesis of Ag and Pd metal nanoparticles: A possible anticancer, and antioxidant applications

The present research aimed develop an innovative and efficient method for fabricating silver and palladium nanoparticles (NPs)by using exopolysaccharide (EPS) from the seaweed-associated endo-symbiotic bacteria Exiguobacterium profundum (OP919469). Through, the application is a combined precipitation approach, EPS acts as a reducing and stabilising agent for the production of NPs. The major functional groups of NPs such as C–H, N–H, C–C, and C–O stretching’s were detected. The structural morphology of NPs showed a mixture of needle, spherical, and triangle-shaped with size between 10 and 50 nm. The purity of EPS was confirmed by high-performance liquid chromatography which revealed 99.81% purity. The NPs revealed strong anti-cancer and antioxidant properties. In addition, the NPs have been shown to dose-dependent toxicity with reduced hatching, survival rate, and abnormalities in zebrafish. The biochemical assay revealed that the EPS loaded NPsdid not induce oxidative stress up to 120 hpf in contrast to hydrogen peroxide which had a significant effect (P < 0.0001) on glutathione-S-transferase, catalase (P < 0.0017), and superoxide dismutase (P < 0.0001). Overall, our finding indicates that the molecular and functional characteristics of EPS and EPS loaded NPs represent future potential applications in the drug delivery and healthcare sectors.

Green Synthesis, Chemical Characterization, Antioxidant, Cytotoxicity and Anticancer Effects of Vanadium Nanoparticles

Silybum marianum is a plant with many remedial properties and may help prevent the cancer spread. Studies in this field show that this plant can reduce the growth of cancer cells. Probably, Silybum marianum will improve the effectiveness of chemotherapy. Also, the side effects of the recent treatments may be reduced by using this plant. The Food and Drug Administration has not confirmed Silybum marianum for the cancer treatment, but it may be effective in the treatment of these cancers: prostate, breast, cervical, blood, small intestine, and skin. Researching formulation of metallic nanoparticles by medicinal plants is the research priority of all countries. In the current experiment, we synthesize the vanadium nanoparticles by the watery extract of the Silybum marianum aerial parts. The characterization was conducted by field emission scanning electron microscopy, transmission electron microscopy, X-ray diffraction analysis, fourier transform infrared, energy-dispersive X-ray spectroscopy, and ultraviolet–visible spectroscopy. The DPPH inhibition efficacy was assessed by the DPPH examination, while the MTT assay was used to evaluate anti-cervical cancer (against LM-MEL-41, HT-3, Ca Ski, DoTc2 4510, SiHa, and C-33 A cells) and cytotoxicity efficacy of vanadium NPs. In XRD, the signals at 2 theta values of 25.13, 27.77, 44.94, 49.52, 66.28, and 70.57 belong to the planes of (202), (103), (401), (205), (406), and (125) respectively. Based on the findings of FE-SEM, the NPs are formed with the morphology of spherical with an aggregation. In FT-IR, the peaks at 416 and 551 cm−1 can be assigned to V–O–V and V–O bonds. The EDS analysis confirms the vanadium presence by the signals at 5.45 (VKβ), 4.98 (VKα), and 0.53 (VLα). The other signals below 0.5 KeV verify the appearance of carbon and oxygen in the green synthetic vanadium nanoparticles. The V nanoparticles IC50 was 126, 157, 165, 125, 132, and 197 μg/mL against LM-MEL-41, HT-3, DoTc2 4510, C-33 A, SiHa, and Ca Ski cervical cancer cells, respectively.

Light-driven soft crawling robots capable of multidirectional locomotion and cargo transport

This work presents a liquid crystal elastomer (LCE)-based light-driven crawling robot capable of rapid multidirectional locomotion and cargo transport. The proposed LCE device consists of two small front legs, two large rear legs, and a concave cargo platform connecting the legs. The device’s locomotion, inspired by the principle of snake-like rectilinear movement, is generated by activating the rear legs with periodic near-infrared (NIR) illumination. The device’s structure was formed monolithically using a lithography-based molding process followed by an LCE stretching process for shape programming. To enhance NIR absorption efficiency, the rear end of the device was coated with a photothermal film consisting of acrylic-based black paint and liquid metal nanoparticles. The device’s speed, which exceeds two body lengths per minute, is among the fastest recorded in published LCE-based, light-driven crawling devices. Furthermore, the device can change the locomotion direction by controlling the actuation sequences of NIR illumination on the rear legs. This research also demonstrated and characterized the device’s load-carrying capability, as it was able to move at about half its maximum speed while carrying a load heavier than itself.

A smartphone-based tunable tyrosinase functional mimic modulated portable amperometric sensor for the rapid and real-time monitoring of catechol

A smartphone-based electrochemical sensor for rapid detection of catechol (CC) was designed. The system contained a smartphone, a hand-held detector, and tyrosinase enzyme mimicking material modified screen-printed carbon electrode (SPCE). Metal nanoparticles confined in porous carbon have been widely used as enzyme mimics owing to their enhanced electrochemical activity. However, the fabrication of enzyme-mimicking catalysts in a scalable and tunable manner is challenging. A two-step synthesis strategy was followed: carbonization of the silica template to form cubic-structured mesoporous carbon (CMC) and high-temperature calcination for copper confinement into CMC (Cu–CMC). The non-covalent interactions enable the Cu precursors to coordinate with the carbon atoms in the face-centered cubic lattice of CMC. The uncalcined material is the as-synthesized (As–Cu–CMC), while the 900 °C calcined are stage 1 (Cu–CMCS1) and stage 2 (Cu–CMCS2) materials with different Cu loadings. The Cu–CMCS2 possess a large pore volume (0.224 cm3g−1) and high surface area (104.2 m2/g). The Cu–CMCS2 modulated sensors enable rapid and real-time detection of CC. Under optimized conditions, the linear range of 1.0–1000 µM (0.0 V vs. integrated Ag/AgCl reference electrode) with the sensitivity and lower detection limit of 10.21 µA µM−1 cm−2 and 0.099 μM (S/N=3) was achieved. The excellent sensor performance is attributed to the increased number of Cu vacancies that mimic the native tyrosinase enzyme. The sensor connected to a portable potentiostat enable high-throughput real-time testing of the CC without sophisticated equipment. Furthermore, the sensor detected CC in green tea and water samples, and the results were validated using UV–visible spectrophotometry and high-performance liquid chromatography.Abbreviations: CMC, cubic-structured mesoporous carbon; Cu–CMCS2, copper loaded stage 2 material; CC, catechol; CMS, cubic mesoporous silica; SPCE, screen-printed carbon electrode; HF, hydrofluoric acid; P123, Pluronic 123; TEOS, Tetraethyl orthosilicate; AA, ascorbic acid; Glu, glucose; HQ, hydroquinone; 4-NP, 4-nitrophenol; CA, caffeic acid; RS, resorcinol; Cu–CMCS1, copper loaded stage 1 material; UV–Vis, UV–visible spectrophotometry; FE-SEM, field-–emission scanning electron microscopy; EDS, energy–dispersive X–-ray spectroscopy; Si, silica; TEM, transmission electron microscopy; NPs, nanoparticles; SAED, selected area electron diffraction; FT-IR, Fourier-Transform Infrared Spectroscopy; BET, Brunauer–Emmett–Teller; BJH, Barrett–Joyner–Halenda; TGA, Thermogravimetric analysis; CV, cyclic voltammetry; ipa, anodic peak current; ECSA, electrochemically active surface area; EIS, electrochemical impedance spectroscopy; Rct, charge-transfer resistance; CA, chronoamperometry; LOD, limit of detection.

Preparation, characterization, and evaluation of an acetylene black polyurethane composite electrode modified with copper nanoparticles for the determination of escitalopram

Escitalopram (ESC) is a widely prescribed antidepressive drug worldwide and must be monitored in biological fluids and environmental samples. Thus the preparation of an acetylene black-polyurethane composite electrode modified with copper metallic nanoparticles by electrodeposition intended for the determination of ESC in synthetic urine and mineral water samples is presented. The surface was further electrochemically pretreated in 0.50 mol/L NaOH in order to obtain a stable mixture of Cu (II) oxides on top of the Cu° nanoparticles. After preconditioning in 0.10 mol/L phosphate buffer pH 7.0, the modified electrode was used in the determination of ESC in the proposed matrixes using CV and DPV, after optimizing experimental parameters. The interaction of the analyte with copper (II) ions promoted a decrease of the Cu(II) reduction peak which was proportional to the ESC concentration in the 0.020–0.10 µmol/L (LOD = (5 ± 1) nmol/L) and 0.040–0.20 µmol/L (LOD = (5.1 ± 0.9) nmol/L) in cyclic voltammetry (CV) and differential pulse voltammetry (DPV) respectively. Interferences from ascorbic acid, uric acid, dopamine and creatinine were evaluated, however the last one present in synthetic urine did not prevented the determination of ESC, as well as the other chemical species naturally present in the mineral water

Biosynthesis and characterization of gold nanoparticles from citrullus colocynthis (L.) schrad pulp ethanolic extract: Their cytotoxic, genotoxic, apoptotic, and antioxidant activities

The age-old discipline of plant therapy has gained renewed importance through the utilization of plants for the synthesis of metal nanoparticles. However, toxicity testing and characterization of the recently synthesized nanomaterials are essential to evaluating their appropriate application. Citrullus colocynthis is a medicinal plant with several health benefits. Herein, we used its ethanolic pulp extract (PE) to manufacture gold nanoparticles (PE-AuNPs). Various approaches were employed to assess the MTT50 and NR50 values of PE and PE-AuNPs at different concentrations in the human hepatocarcinoma cell line (HepG2). The study aimed to assess the genotoxic effects and in vivo toxicity of PE and PE-AuNPs at MTT50 dosages. The quasi-spherical, cubic/triangular prisms, and nail-looking particles exhibited no antioxidant properties. They had an absorbance peak between 540 and 560 nm, diameters of less than 20 nm, hydrodynamic diameters of 177.9 nm, and a negative surface charge (−10.3 mV). The significant role of plant phytochemicals in the formation of metal nanoparticles is confirmed by the diminished antioxidant capacity of extract residues following PE-AuNP synthesis. PE-AuNPs exhibited in vivo and cytotoxic effects at relatively lower concentrations compared to PE. In contrast to PE, PE-AuNPs exhibited lower genotoxic at MTT50 dosages. Despite having MTT50 values of approximately 1.95 ± 0.06 and 0.89 ± 0.03 mg/ml, PE and PE-AuNPs can still be considered biocompatible. Nonetheless, our results suggest that the characteristics of recently produced nanoparticles can differ from those of the matching plant. Further investigation can provide a better understanding of the possible therapeutic and pharmacological impacts of PE-AuNPs.

Achieving Optical Refractive Index of 10-Plus by Colloidal Self-Assembly.

This study demonstrates the developments of self-assembled optical metasurfaces to overcome inherent limitations in polarization density (P) and high refractive indices (n) within naturally occurring materials. The Maxwellian macroscopic description establishes a link between P and n, revealing a static limit in natural materials, restricting n to ≈4.0 at optical frequencies. Previously, it is accepted that self-assembly enables the creation of nanogaps between metallic nanoparticles (NPs), boosting capacitive enhancement of P and resultant exceptionally high n at optical frequencies. The work focuses on assembling gold (Au) NPs into a closely packed monolayer by rationally designing the polymeric ligand to balance attractive and repulsive forces, in that polymeric brush-mediated self-assembly of the close-packed Au NP monolayer is robustly achieved over a large-area. The resulting monolayer of Au nanospheres (NSs), nanooctahedras (NOs), and nanocubes (NCs) exhibits high macroscopic integrity and crystallinity, sufficiently enough for pushing n to record-high regimes. The systematic comparisons between each differently shaped Au NP monolayers elucidate the significance of capacitive coupling in achieving an unnaturally high n. The achieved n of 10.12 at optical frequencies stands as a benchmark, highlighting the potential of polyhedral Au NPs in advancing optical metasurfaces.

Metal nanoparticles and their toxicity impacts on microorganisms

Metal nanoparticles and their toxicity impacts on microorganisms

The effect of calcination gas atmosphere on the structural organization of Ru/Ce0.75Zr0.25O2 catalysts for CO2 methanation

In this study, supported 5 wt% Ru/Ce0.75Zr0.25O2 catalysts were prepared by sorption-hydrolytic deposition technique, followed by calcination under different conditions, namely in reductive H2/N2 (Ru/CeZr_red) and oxidative air (Ru/CeZr_ox) atmospheres. A thorough characterization of the catalysts was carried out by XRD, CO chemisorption, HRTEM, Raman spectroscopy, XPS, and in situ DRIFTS. The findings showed that the choice of the calcination atmosphere has a great impact on the structural organization of the catalyst. Calcination in air results in the formation of the larger crystalline RuO2 particles, which tend to enlarge upon reduction under CO2 methanation conditions. The reductive treatment results in a much higher dispersion of supported Ru species and a more pronounced metal-support interaction (MSI). In the Ru/CeZr_red catalyst, a large amount of atomic scale Ru species was detected along with metallic Ru nanoparticles and clusters. However, it was found that the superiority of the Ru/CeZr_red catalyst in the Ru dispersion did not result in the significant advantage in the CO2 methanation activity. In situ DRIFTS results suggested that the MSI affects the ability of Ru species to adsorb and activate reagent molecules, in particular, enhances the adsorption strength of the intermediate CO species.

Investigation of the preparation and performance of Ag-modified ZnO nanowall ultraviolet detector

In this paper, silver (Ag) nanoparticle-modified zinc oxide (ZnO) nanowall photoconductive ultraviolet photodetector was prepared by using magnetron sputtering technology, electron beam evaporation method and hydrothermal method. The results showed that ZnO nanowalls exhibited a hexagonal wurtzite structure. ZnO nanowalls grew uniformly perpendicular to the substrate, and metallic Ag nanoparticles were uniformly attached to the surface of ZnO nanowalls, effectively improving the ZnO nanowall absorption capability in the ultraviolet light region. The dark current of the Ag-modified ZnO nanowall UV detector deposited by sputtering for 40[Formula: see text]s was 0.042[Formula: see text]mA, revealing a decrease of 44%. Under the irradiation of ultraviolet light with a wavelength of 325[Formula: see text]nm, the photocurrent reached 3.088[Formula: see text]mA, which increased by four times. The responsivity increased from 27.29 to 101.07[Formula: see text]mA/W, and the sensitivity increased from 8.07 to 73.52. In addition to the good repeatability and stability, the response time was reduced by 64%, and the recovery time was decreased by 50%.

Sponge-shaped Au nanoparticles: A stand-alone metallic photocatalyst for driving the light-induced CO2 reduction reaction.

Coinage metal nanoparticles (NPs) enable plasmonic catalysis by generating hot carriers that drive chemical reactions. Making NPs porous enhances the adsorption of reactant molecules. We present a dewetting and dealloying strategy to fabricate porous gold nanoparticles (Au-Sponge) and compare their CO2 photoreduction activity with respect to the conventional gold nanoisland (Au-Island) morphology. Porous gold nanoparticles exhibit an unusually broad and red-shifted plasmon resonance which is in agreement with the results of finite difference time domain (FDTD) simulations. The key insight of this work is that the multi-step reduction of CO2 driven by short-lived hot carriers generated by the d → s interband transition proceeds extremely quickly as evidenced by the generation of methane. A 3.8-fold enhancement in the photocatalytic performance is observed for the Au-Sponge in comparison to the Au-Island. Electrochemical cyclic voltammetry measurements confirm the 2.5-fold increase in the surface area and roughness factor of the Au-Sponge sample due to its porous nature. Our results indicate that the product yield is limited by the amount of surface adsorbates i.e. reactant-limited. Isotope-labeled mass spectrometry using 13CO2 was used to confirm that the reaction product (13CH4) originated from CO2 photoreduction. We present the plasmon-mediated photocatalytic transformation of 4-aminothiophenol (PATP) into p,p'-dimercaptoazobenzene (DMAB) using Au-Sponge and Au-Island samples.

Edge‐Effect Modulated Noble Metal Electrocatalysts for Efficient and pH‐Universal Hydrogen Evolution Reaction

AbstractThe catalytic activity of metal nanoparticles is closely pertinent to the substrate, while the influence of the support on the catalytic activity is acquainted scarcely. Herein, the edge selective decoration of noble metal nanoparticles into an edge‐rich carbon foam (CF) matrix for efficient pH‐universal hydrogen evolution (HER) reaction is reported. The highly localized density of states of the graphene edges enables increased reactivity to noble metal nanoparticles and tunes their electronic states. As expected, the Pt nanoparticles decorated on CF (Pt NPs@CF) exhibit low overpotentials (η10) of only 35, 49, and 53 mV under acidic, alkaline, and neutral conditions, respectively. Moreover, it can deliver the ampere‐level current density of 1000 mA cm−2 with an overpotential of 97 mV in acidic solutions. Above all, the other noble metal NPs decorated on CF also possess efficient pH‐universal HER performance. This work presents a new avenue for developing high‐activity electrocatalysts via support engineering.