Synthesis Of Platinum Nanoparticles Research Articles

Green Synthesis of Platinum Nanoparticles Using Polymer Bio-reduction Approach and Their Photocatalytic Organic Dye Degradation

Green Synthesis of Platinum Nanoparticles Using Polymer Bio-reduction Approach and Their Photocatalytic Organic Dye Degradation

Platinum nanoparticle synthesis in engineered organic nanoscale reactors for efficient oxygen electro-reduction in alkaline conditions

Platinum nanoparticle synthesis in engineered organic nanoscale reactors for efficient oxygen electro-reduction in alkaline conditions

Reduced graphene oxide-functionalized polymer microneedle for continuous and wide-range monitoring of lactate in interstitial fluid

Despite substantial developments in minimally invasive lactate monitoring microneedle electrodes, most such electrode developments have focused on either sensitivity or invasiveness while ignoring a wide range of detection, which is the most important factor in measuring the normal range of lactate in interstitial fluid (ISF). Herein, we present a polymer-based planar microneedle electrode fabrication using microelectromechanical and femtosecond laser technology for the continuous monitoring of lactate in ISF. The microneedle is functionalized with two-dimensional reduced graphene oxide (rGO) and electrochemically synthesized platinum nanoparticles (PtNPs). A particular quantity of Nafion (1.25 wt%) is applied on top of the lactate enzyme to create a diffusion-controlled membrane. Due to the combined effects of the planar structure of the microneedle, rGO, and membrane, the biosensor exhibited excellent linearity up to 10 mM lactate with a limit of detection of 2.04 μM, high sensitivity of 43.96 μA mM−1cm−2, a reaction time of 8 s and outstanding stability, selectivity, and repeatability. The feasibility of the microneedle is evaluated by using it to measure lactate concentrations in artificial ISF and human serum. The results demonstrate that the microneedle described here has great potential for use in real-time lactate monitoring for use in sports medicine and treatment.

From Basic Research on Supported-Metal Catalysts to their Practical Applications for Reduction of Food Waste

Abstract Supported metal catalysts are one of the most important heterogeneous catalysts, and they are widely used in chemical processes such as naphtha reforming, purification of exhaust gas from automobiles and so on. However, rational design of supported metal catalysts is still a target in heterogeneous catalysis. The author had a hypothesis that metal nanoparticles in ordered pores of zeolite or mesoporous silica may exhibit novel catalytic properties. Based on this idea, we used micropores of zeolites to accommodate metal carbonyl clusters, and then mesoporous silica to prepare metal nanoparticles. First, we studied ship-in-bottle synthesis of Rh carbonyl clusters in zeolite and its reactivity. Rh6(CO)16 was synthesized in NaY zeolite accompanied with formation of a mononuclear Rh(CO)2, which acted as a carrier of 13CO in 12CO-13CO exchange reaction. Then we worked on synthesis of platinum nanoparticles in mesoporous silica, and found that high activity in preferential oxidation of CO in hydrogen and in low-temperature oxidation of ethylene. The high catalytic performance in ethylene oxidation has led to practical application of platinum/silica catalysts for preservation of fruits and vegetables, resulting in reduction of food waste. This article describes the development process of this research.

Antioxidant Activity of Green Synthesized Platinum Nanoparticles by Using Tornabea scutellifera Extract

First time in this study Tornabea scutellifera extract were used for synthesis of Platinium nanoparticles (Pt NPs). The DPPH scavenging activity of T. scutellifera-based Pt NPs was determined and its usability as antioxidant activity was evaluated. With characterization tests, it was observed that Pt NPs were in spherical structure and had an average diameter of 88.7 nm. Functional groups that play a role in the synthesis were determined by FT-IR analysis with the peaks determined at 1623 cm-1, 1146 cm-1, 1042 cm-1, 987 cm-1, 625 cm-1 ve 558 cm-1. Elemental structure (presence of Pt) was revealed by EDX analysis. It was determined that T. scutellifera-based Pt NPs exhibited anti-oxidant activity against DPPH (184.06 µg/ml, R2=0.8727). It is thought that the study can be used in nanotechnology-related multidisciplinary studies.

Synthesis of Platinum Nanoparticles Supported on Fused Nanosized Carbon Spheres Derived from Sustainable Source for Application in a Hydrogen Generation Reaction

The dwindling supply of fossil fuels has prompted the search for an alternative energy source that could effectively replace them. Potential renewable energy sources such as solar, wind, tidal, and geothermal are all promising but each has its own drawbacks. Hydrogen gas on the other hand can be combusted to produce energy with only water as a byproduct and can be steadily generated via the aqueous media hydrolysis reaction of Sodium Borohydride (NaBH4). This study successfully synthesized fused carbon spheres derived from sugar and decorated them with platinum nanoparticles to form a novel composite material (PtFCS) for catalyzing this reaction. The platinum nanoparticles were produced by reducing chloroplatinic acid in a solution with sodium borohydride and using sodium citrate as a capping agent for the nanoparticles. Transmission electron microscopy (TEM), Energy-dispersive X-ray spectroscopy (EDS), Fourier-transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD) were used to characterize and determine the size and shape of the Pt nanoparticles (PtNPs) and fused carbon spheres. TEM was able to determine the average size of the fused carbon spheres to be 200 nm and the average size for the PtNPs to be 2–3 nm. The PtFCS composite was tested for its ability to catalyze the hydrolysis of NaBH4 under various reaction conditions including various solution pH, various temperatures, and various dosages of sodium borohydride. The catalyst was found to perform the best under acidic solution conditions (pH 6), producing hydrogen at a rate of 0.0438 mL/mgcat·min. The catalyst was determined to have an activation energy of 53.0 kJ/mol and could be used multiple times in succession with no loss in the volume of hydrogen produced. This sugar-derived composite catalyst shows promise and could be implemented as a sustainable catalyst for the generation of hydrogen fuel.

The Kinetics of the Redox Reaction of Platinum(IV) Ions with Ascorbic Acid in the Presence of Oxygen

In this work, the kinetics of the redox reaction between platinum(IV) chloride complex ions and ascorbic acid is studied. The reduction process of Pt(IV) to Pt(II) ions was carried out at different reagent concentrations and environmental conditions, i.e., pH (2.2–5.1), temperature (20–40 °C), ionic strength (I = 0.00–0.40 M) and concentrations of chloride ions (0.00–0.40 M). The kinetic traces during the reduction process were registered using stopped-flow spectrophotometry. Based on the kinetic traces, the rate constants were determined, and the kinetic equations were proposed. It was shown that in the mild acidic medium (pH = 2.5), the reduction process of Pt(IV) to Pt(II) ions is more complex in the presence of oxygen dissolved in the aqueous solutions. For these processes, the values of the enthalpy and entropy of activation were determined. Moreover, the mechanism of the reduction of Pt(IV) to Pt(II) ions was proposed. The presented results give an overview of the process of the synthesis of platinum nanoparticles in the solution containing oxygen, in which the reduction process of Pt(IV) to Pt(II) ions is the first step.

Synthesis and Evaluation of Platinum Nanoparticles Using F. Carica Fruit Extract and Their Antimicrobial Activities

Abstract In this manuscript, a simple new method for the green synthesis of platinum nanoparticles (Pt NPs) utilizing F. carica Fig extract as reducing agent for antimicrobial activities was reported. Simultaneously, the microstructural and morphological features of the synthesized Pt NPs were thoroughly investigated. In particular, the attained Pt NPs exhibited spherical shape with diameter range of 5-30 nm and root mean square of 9.48 nm using Transmission Electron Microscopy (TEM) and Atomic Force Microscopy (AFM), respectively. Additionally, the final product (Pt NPs) was screened as antifungal and antibacterial agent against Candida and Aspergillus species as well as Gram-positive Staphyllococcus aureus and Gram-negative Acinetobacter species, respectively. Accordingly, the synthesized NPs demonstrated inhibition zones of 36 and 28 mm against fungal and bacterial species, respectively. The presented Pt NPs play an active role in both antifungal and antibacterial activities which indicates the presence of a well-regulated nano-materials system for biomedical application.

Stretchable Low-Impedance Conductor with Ag-Au-Pt Core-Shell-Shell Nanowires and in Situ Formed Pt Nanoparticles for Wearable and Implantable Device.

Mechanically soft metallic nanocomposites have gained much attention as a key material for intrinsically stretchable biointegrated devices. However, it has been challenging to develop a stretchable conductive nanocomposite with all the desired material characteristics including high conductivity, high stretchability, low cytotoxicity, and low impedance. Here, we present a material strategy for the stretchable conductive nanocomposite, particularly emphasizing low impedance, by combining silver-gold-platinum core-shell-shell nanowires and homogeneously dispersed in situ synthesized platinum nanoparticles (Pt NPs). The highly embossed structure of the outermost Pt shell, together with the intrinsic electrical property of Pt, contributes to minimizing the impedance. The gold-platinum double-layer sheath prevents leaching of cytotoxic Ag ions, thus improving biocompatibility. Homogeneously dispersed Pt NPs, synthesized in situ during fabrication of the nanocomposite, simultaneously enhance conductivity, reduce impedance, and improve stretchability by supporting the percolation network formation. This intrinsically stretchable nanocomposite conductor can be applied to wearable and implantable bioelectronics for recording biosignals and delivering electrical stimulations in vivo.

Surfactant- and Ligand-Free Synthesis of Platinum Nanoparticles in Aqueous Solution for Catalytic Applications

The synthesis of surfactant-free and organic ligand-free metallic nanoparticles in solution remains challenging due to the nanoparticles’ tendency to aggregate. Surfactant- and ligand-free nanoparticles are particularly desirable in catalytic applications as surfactants, and ligands can block access to the nanoparticles’ surfaces. In this contribution, platinum nanoparticles are synthesized in aqueous solution without surfactants or bound organic ligands. Pt is reduced by sodium borohydride, and the borohydride has a dual role of reducing agent and weakly interacting stabilizer. The 5.3 nm Pt nanoparticles are characterized using UV-visible spectroscopy and transmission electron microscopy. The Pt nanoparticles are then applied as catalysts in two different reactions: the redox reaction of hexacyanoferrate(III) and thiosulfate ions, and H2O2 decomposition. Catalytic activity is observed for both reactions, and the Pt nanoparticles show up to an order of magnitude greater activity over the most active catalysts reported in the literature for hexacyanoferrate(III)/thiosulfate redox reactions. It is hypothesized that this enhanced catalytic activity is due to the increased electron density that the surrounding borohydride ions give to the Pt nanoparticle surface, as well as the absence of surfactants or organic ligands blocking surface sites.

Tunable Aryl Alkyl Ionic Liquid Supported Synthesis of Platinum Nanoparticles and Their Catalytic Activity in the Hydrogen Evolution Reaction and in Hydrosilylation.

Tunable aryl alkyl ionic liquids (TAAILs) are ionic liquids (ILs) with a 1-aryl-3-alkylimidazolium cation having differently substituted aryl groups. Herein, nine TAAILs with the bis(trifluoromethylsulfonyl)imide anion are utilized in combination with and without ethylene glycol (EG) as reaction media for the rapid microwave synthesis of platinum nanoparticles (Pt-NPs). TAAILs allow the synthesis of small NPs and are efficient solvents for microwave absorption. Transmission electron microscopy (TEM) shows that small primary NPs with sizes of 2 nm to 5 nm are obtained in TAAILs and EG/TAAIL mixtures. The Pt-NPs feature excellent activity as electrocatalysts in the hydrogen evolution reaction (HER) under acidic conditions, with an overpotential at a current density of 10 mA cm-2 as low as 32 mV vs the reversible hydrogen electrode (RHE), which is significantly lower than the standard Pt/C 20% with 42 mV. Pt-NPs obtained in TAAILs also achieved quantitative conversion in the hydrosilylation reaction of phenylacetylene with triethylsilane after just 5 min at 200 °C.

An effective bio-inspired synthesis of platinum nanoparticles using Caulerpa sertularioides and investigating their antibacterial and antioxidant activities.

In this study, we report the synthesis of platinum nanoparticles (Cs-PtNPs) using an aqueous extract of Caulerpa sertularioides as a reducing agent. Cs-PtNPs were characterized by UV-Vis spectroscopy, fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), field emission electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDAX), high-resolution transmission electron microscopy (HR-TEM) and dynamic light scattering (DLS) analysis. Cs-PtNPs are spherical with a particle size of 6-22nm. Cs-PtNPs have been shown to have highly effective antioxidant activities with 74% for DPPH, 63% for reducing power, and 59% for total antioxidant at 1mg/ml, and results were compared with standard L-ascorbic acid. Furthermore, the Cs-PtNPs demonstrated excellent antibacterial activity against the Gram-negative bacteria, Vibrio parahaemolyticus with the highest zone of inhibition (18mm) at 50µg/ml. Moreover, Artemia nauplii showed less toxicity when treated with Cs-PtNPs at 150µg/ml, indicating that the Cs-PtNPs are less toxic and environment friendly.

Inkjet-Assisted Electroformation of Magnetically Guidable Water Striders for Interfacial Microfluidic Manipulation.

Gerridae, colloquially called water striders, are a peculiar class of insects characterized by the extraordinary ability to walk on the surface of water bodies. Owing to this capacity, they constitute an ideal source of inspiration for designing untethered microdevices capable of navigating the interface between two fluids. Such steerable micrometric objects can be of great interest for various applications, ranging from the handling of floating objects to the remote control of microreactions and the manipulation of self-assembled monolayers. This paper describes the realization of artificial water striders via an inkjet-assisted electroforming approach. Inkjet deposition patterns the negative mask, which is subsequently filled with different layers of metals through electroforming. One of such layers is the magnetic alloy NiFe, which allows wireless propulsion of the striders by means of externally applied magnetic fields. The magnetic actuation tests prove good maneuverability at the water-air and silicone oil-air interfaces, with superior control over the speed and position of the devices. The surface of the devices is modified to tune its superficial energy in order to maximize buoyancy on these different combinations of fluids. A magnetic field-controlled strider manipulates a droplet and demonstrates collecting oil microdroplets and synthesizing platinum nanoparticles by chemical microreactions. Finally, the remotely operated microrobot could be employed in laboratories as a real avatar of chemists.

Role of green synthesized platinum nanoparticles in cytotoxicity, oxidative stress, and apoptosis of human colon cancer cells (HCT-116)

Progresses in the medicinal application of nanocompounds were accepted for the treatment of cancer. Nanoparticles-based therapy is of benefit for effective biodistribution and specific targeting. The current study investigated the anticancer effect of green synthesized platinum nanoparticles (PtNPs) against colon cancer cells (HCT-116). Flow cytometry and ELISA techniques were employed for detecting apoptotic and oxidative stress markers. Furthermore, PtNPs-lycopene (PtNPs-LP) on cell migration and invasion of HCT-116 cells was also examined. The PtNPs-LP was capable of diminishing cell proliferation and viability of HCT-116 cells in a dose-dependent mode. After treatment with PtNPs-LP, a significant increase in pro-apoptotic Bax and caspase-3 and a decrease in anti-apoptotic Bcl-2 was observed in treated cells that subsequently released cytochrome C into its cytoplasm, initiating cell death. Moreover, PtNPs-LP induced excessive generation of reactive oxygen species (ROS) and oxidative stress in cancer cells. In conclusion, PtNPs-LP exerts an antitumor effect against colon cancer cells via mediating important mechanisms such as cytotoxicity, apoptosis, and oxidative stress.

Green Synthesis of Platinum Nanoparticles for Biomedical Applications.

The diverse biological properties of platinum nanoparticles (PtNPs) make them ideal for use in the development of new tools in therapy, diagnostics, and other biomedical purposes. "Green" PtNPs synthesis is of great interest as it is eco-friendly, less energy-consuming and minimizes the amount of toxic by-products. This review is devoted to the biosynthesis properties of platinum nanoparticles based on living organisms (bacteria, fungi, algae, and plants) use. The participation of various biological compounds in PtNPs synthesis is highlighted. The biological activities of "green" platinum nanoparticles (antimicrobial, anticancer, antioxidant, etc.), the proposed mechanisms of influence on target cells and the potential for their further biomedical application are discussed.

Green synthesis of platinum nanoparticles as a robust electrocatalyst for methanol oxidation reaction: Metabolite profiling and antioxidant evaluation

A novel, low-cost, and environmentally friendly method of synthesising biogenic platinum nanoparticles (Pt NPs) was employed using biomass sugar cane (Saccharum officinarum L.) bagasse extract (SBE) as the reducing agent. Pt NPs derived from this biosynthesis route were thoroughly characterised by High-resolution transmission electron microscopy (HRTEM), Field emission scanning electron microscopy (FESEM), Energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS) analysis. Due to the involvement of bio-reductive metabolites during biosynthesis, their metabolite profiles were identified using gas chromatography-mass spectrometry (GC-MS) and in-vitro antioxidant activities. Eleven major metabolite compounds from the SBE classified as phenol, pyrazole, furan, pyran, epoxide, long-chain fatty acid, sterol glycoside, and mixed oxygenated compounds may be responsible for the bio-reduction process. The biogenic Pt NPs endowed a high antioxidant property that can scavenge DPPH free radicals by 81.9%, with an inhibitory effect (IC50) of 37.60 μg/mL and ferric reducing antioxidant power assay (FRAP) of 57.58 μmol FeSO4/g. Furthermore, the biogenic Pt NPs deliver superior electrocatalytic activity in methanol oxidation reactions with tunable Pt ions concentration, PtCl62−, from 0.5 to 1.75 mM, with a maximum electrochemical active surface area (ECSA) of 93.41 m2 g−1 and a mass activity/specific activity of 581.50 mA mg−1/1.25 mA cm−2Pt, which is 3.67 times higher than that of commercial Pt black (158.12 mA mg−1). This study demonstrates that green chemical reduction using plant extracts is a viable method for producing biogenic Pt NPs for energy conversion and health applications, owing to its improved electrocatalytic activity and profound antioxidant properties.

Green synthesis of platinum nanoparticles by Nymphaea tetragona flower extract and their skin lightening, antiaging effects

Platinum nanoparticles (PtNPs) were green synthesized by using chloroplatinic acid (H2PtCl6) as raw material and Nymphaea tetragona (N. tetragona) flower extract as the capping and reducing agents to improve skin health. Size-tunable PtNPs were obtained by volume ratios of the initial H2PtCl6/N. tetragona of 1:1 and 1:4, in which PtNPs prepared by the ratio of 1:1 and 1:4 was defined as L1-PtNPs and L4-PtNPs. Their characterizations were investigated by UV–visible spectroscopy, TEM, XRD and FTIR spectroscopy. TEM image analysis showed the particles were well dispersed with the average particle diameters of L1 and L4-PtNPs were 4.04 ± 1.31 nm and 2.01 ± 0.80 nm, respectively. The synthesized PtNPs showed effective antioxidant property and anti-tyrosinase activity in vitro. And further experiments exclaimed that PtNPs can significantly inhibit tyrosinase activity and UVB-induced melanin biosynthesis in A375 cells. This study also revealed PtNPs can promote collagen I biosynthesis in HFF-1 cells by activating the TGF-β/Smad pathway. This research showed the potential efficacy of PtNPs in the skin field and provided evidence for people to consider applying PtNPs to skin protection.

Fabrication of Pt nanoparticles by nanosecond pulsed laser ablation in aqueous solution of ethanol using KrF excimer laser

The present paper presents the premiere synthesis of platinum nanoparticles (Pt-NPs) by pulsed laser ablation in aqueous ethanol solution (PLAL) using an excimer nanosecond KrF laser. The impact of the laser fluence, repetition rate (RR) and ethanol concentrations on the optical and morphological properties of the obtained Pt-NPs was investigated. The optical characteristics has been assessed by transmission spectroscopy in the UV/Vis region, and the issues associated to the volatile component’s evaporation are discussed. Detailed information on the morphological properties was acquired via High-Resolution Scanning Transmission Electron Microscopy (HR-STEM). Mean size values in the range of 1.7–2.45 nm with narrow standard deviations from ± 0.6 up to ± 1.1 nm, were established for the synthesized Pt-NPs, that showed a certain level of aggregation. The smallest mean size value, 1.7 nm, was found for the sample produced using 2.3 Jcm−2 laser fluence, 10 Hz RR in 60 % ethanol concentration. The narrowest size distribution (±0.6 nm) was achieved with the same laser fluence and RR in 80 % aqueous ethanol solution. In addition, the metallic character (Pt) of the atoms forming the NPs was confirmed by Direct Analysis in Real Time Mass Spectrometry (DART-MS). The formation of face-centered cubic phase for Pt-NPs with interplanar distances of 0.25 and 0.19 nm for (200) and (111) crystalline planes, respectively, was revealed by X-ray diffraction (XRD). These results are in good agreement with those from HR-STEM analysis, where similar interplanar distances were obtained for individual NPs.

Cerium Oxide on a Fluorinated Carbon-Based Electrode as a Promising Catalyst for Hypochlorite Production.

Sodium hypochlorite (NaOCl) is widely used as a disinfectant agent for water treatment and surface cleaning. A straightforward way to produce NaOCl is by the electrolysis of an aqueous sodium chloride (NaCl) solution. This process presents several side reactions decreasing its efficiency with hypochlorite reduction on the cathode surface being one of the main detrimental reactions. In this work, we have studied carbon-based electrodes modified with cerium oxide (CeO2), fluorine, and platinum nanoparticles as cathodes for hypochlorite production. Fluorination was carried out electrochemically; the polyol method was used to synthesize platinum nanoparticles; and the hydrothermal process was applied to form a CeO2 layer. Scanning electron microscopy, FTIR, and inductively coupled plasma (ICP) indicated the presence of cerium oxide as a film, fluorine groups on the substrate, and a load of 3.2 mg/cm2 of platinum nanoparticles and 2.7 mg/cm2 of CeO2. From electrochemical impedance spectroscopy, it was possible to demonstrate that incorporating platinum and fluorine decreases the charge transfer resistance by 16% and 28%, respectively. Linear sweep voltammetry showed a significant decrease in hypochlorite reduction when the substrate was doped with fluorine from −16.6 mA/cm2 at −0.6 V to −9.64 mA/cm2 that further reduced to −8.78 mA/cm2 with cerium oxide covered fluorinated electrodes. The performance of the cathode materials during hypochlorite production improved by 80% compared with pristine activated carbon cloth (ACC) electrodes. The improvement toward hindering NaOCl reduction is probably caused by the incorporation of a partial negative charge upon doping with fluorine.

Optimization of biogenic synthesis of biocompatible platinum nanoparticles with catalytic, enzyme mimetic and antioxidant activities

Owing to platinum's nobility, catalytic potential and vast range of possible biomedical applications, synthesis of platinum nanoparticles is attracting the attention of scientists worldwide. Though the plant mediated methods are simple and easy, they require fine tuning of reaction parameters so as to synthesize nanoparticles of desired properties. The present study aimed to optimize the food waste almond skin extract mediated synthesis of biocompatible platinum nanoparticles with catalytic, enzyme-mimicking, and antioxidant activities. The optimization of reaction parameters indicated that 10 mM of precursor in 2:1 ratio with extract, pH 9, and incubation at 90 °C for 14 min were the optimum parameters. The characterization using various spectroscopic and imaging techniques indicated that platinum nanoparticles were 6–8 nm in size, face centered cubic, irregularly shaped, and negatively charged. When tested for catalytic activity, platinum nanoparticles catalyzed highest of 90.39% reduction of 4-nitrophenol in 16 min. The reaction containing 30 ppm of 4-nitrophenol, catalyst dosage of 0.6 mg/mL, and pH 10 followed pseudo-first order kinetics. Furthermore, platinum nanoparticles were found to possess amylase-mimicking activity of 3.83 μg/mL/min. In addition, platinum nanoparticles showed strong antioxidant activities in a dose-dependent manner signifying them as potentially good antioxidant agents. When tested for cytotoxicity, peripheral blood mononuclear cells were found unaffected when treated with relatively high concentrations (100 μg/mL) of PtNP demonstrating good biocompatibility. Thus, the present study successfully demonstrated the use of almond skin extract as food waste for the biogenic synthesis of biocompatible platinum nanoparticles with biological activities.