Pt Nanoparticles Research Articles

Highly sensitive glutamate biosensor based on platinum nanoparticles decorated MXene-Ti3C2Tx for l-glutamate determination in foodstuffs

In this study, we developed a highly sensitive glutamate biosensor based on Pt nanoparticles (PtNP) decorated two-dimensional nanomaterial MXene-Ti3C2Tx for sensitive analysis of monosodium glutamate (MSG) in food samples. The morphology of PtNP@MXene-Ti3C2Tx was characterized by SEM, which confirmed the successful synthesis of the nanocomposite. The electrochemical experiments were carried out after optimizing working conditions, and a linear relationship was established between the current response and MSG content. The biosensor exhibited a good linear relationship with a correlation coefficient (R2) of 0.9948 in a range of 10–110 μmol/L, and it also had excellent sensitivity (1.5906 nA/(μmol/L)) and a low detection limit (0.45 μmol/L). The biosensor exhibited high selectivity towards glutamate, and it could hold over 70% of its initial sensitivity for 28 days when stored under optimal conditions. The analytical recovery of added MSG (50 and 100 μmol/L) in the vegetable soup was 87.04 and 106.81 g/100 g, respectively. The biosensor was also used successfully to test MSG content in soy sauce, stock cube, and mushroom seasoning. Hence, the constructed glutamate biosensor would be a suitable method for rapid detection of MSG in foodstuffs.

Electrooxidation of 1-propanol on the mixture of nanoparticles of Pt and RuO2

Electrooxidation of 1-propanol on the mixture of nanoparticles of Pt and RuO2

Efficient Oxidase Biosensors Based on Bioelectrocatalytic Surfaces of Electrodeposited Ferrocenyl Polycyclosiloxanes—Pt Nanoparticles

The in-situ synthesis of catalytic surfaces with metallic nanoparticles must overcome the issues related to particle aggregation and polydispersity in the particle size. This work achieves it by using two electrodeposited ferrocenyl polycyclosiloxane polymers (MFPP and FPP) as templates for electro-synthesize Pt nanoparticles (PtNPS). In addition, this new electrode surface combines two efficient electrocatalysts: Ferrocene and Pt nanoparticles, with synergistic biocatalytic properties that constitute an electrocatalytic framework for the covalent immobilization of xanthine oxidase. In this work, we present the results of the kinetic, electrochemical and analytical studies of the prepared electrodes. These results showed that the PtNPs/FPP system is the best bioelectrocatalytic surface and improves other more complex xanthine oxidase devices based on the hydrogen peroxide oxidation, allowing the use of lower measuring potential with good sensitivity, wider linear ranges and low detection limits. In addition, this electrode provides the novelty of allowing the measurement of xanthine through the enzymatic consumption of oxygen at potential −0.1 V with a sensitivity of 1.10 A M−1 cm−2, linear ranges of 0.01–0.1 and 0.1–1.4 mM, low detection limit (48 nM) and long-term stability. The new device has been successfully applied to the determination of xanthine in fish meat.

Effect of water treatment and Ce doping of Pt/Al2O3 catalysts on Pt sintering and propane oxidation

The effect of Ce doping and pretreatment of Pt/Al2O3 on its catalysis of propane oxidation was investigated after aging the catalysts. The Ce amount and pretreatment conditions were varied, and the propane oxidation activity was measured. The properties of the catalysts were investigated by means of XRD, STEM-EDX, FT-IR, and H2-TPR. The size of the Pt nanoparticles (PtNPs) decreased for water-treated catalysts doped with a small amount of Ce, suggesting that water treatment of Ce-doped catalysts inhibits Pt sintering. The minimum PtNP size was obtained with ca. 3.6 wt% of Ce. The Ce species with less than 3.6 wt% existed in a dispersed state, whereas above this value, CeO2 particulates co-existed. The propane oxidation temperature of the water-treated catalysts was lowered to an extent that depended on the Ce content. This tendency is consistent with the PtNP size in the catalysts. It is considered that highly dispersed Ce species take a primary role in promoting propane oxidation on PtNPs. The reduction temperature of Ce species on water-treated catalysts was lower than that of untreated catalysts, probably owing to a stronger interaction between Pt and Ce, demonstrated by FT-IR measurements. The increased reducibility of Ce species may be the reason for the improved oxidation activity of the catalysts.

Fly Ash Waste Recycling by Pt/TiO2 Incorporation for Industrial Dye Removal.

New materials are obtained by transforming fly ash wastes into a valuable composite, with tandem adsorption and photodegradation properties. Mild hydrothermal synthesis, from titanium dioxide, platinum nanoparticles and zeolite materials obtained from a waste, fly ash, as support, was involved in the composite preparation. The platinum nanoparticles extended the photocatalytic activity of the composite in visible range (Eg = 2.1 eV). The efficiency of tandem adsorption and photocatalytic activity of the new composite were determined to be 25% for Bemacid Blau and 43.89% for Bemacid Rot after 360 min, the irradiation time. The addition of H2O2 improves the process efficiency up to 80.70% and 93.43%, respectively. The Pt nanoparticle (PtNP) contribution led to the band gap energy change to Vis light (400 nm), thus suggesting the possibility of photocatalysis under the action of a fraction of natural light.

3D Prussian blue/Pt decorated carbon nanofibers based screen-printed microchips for the ultrasensitive hydroquinone biosensing

Nowadays, water pollution has become more serious, greatly affecting human life and healthy. Electrochemical biosensor, a novel and rapid detection technique, plays an important role in the real-time and trace detection of water pollutants. However, the stability and sensitivity of electrochemical biosensors remain a great challenge for practical detections in real samples to the strong interferences derived from complex components and coagulation effects. In this work, we reported a novel three-dimensional architecture of Prussian blue nanoparticles (PBNPs)/ Pt nanoparticles (PtNPs) composite film, using 3D interweaved carbon nanofibers as a supporting matrix, for the construction of screen-printed microchips-based biosensor. PtNPs with diameters of ~2.5 nm was highly dispersed on the carbon nanofibers (CNFs) to build a 3D skeleton nanostructure through a solvothermal reduction. Subsequently, uniform PBNPs were in-situ self-assembled on this skeleton to construct a 3D architecture of PB/Pt-CNF composite film. Due to the synergistic effects derived from this special feature, the as-prepared hydroquinone (HQ) biosensor chips can synchronously promote both surface area and conductivity to greatly enhance the electrocatalysis from enzymatic reaction. This biosensor has exhibited a high sensitivity of 220.28 μA·L·mmol−1·cm−2 with an ultrawide linear range from 2.5 μmol·L−1 to 1.45 mmol·L−1 at a low potential of 0.15 V, as well as the satisfactory reproducibility and usage stability. Besides, its accuracy was also verified in the assays of real water samples. It is highly expected that the 3D PB/Pt-CNF based screen-printed microchips will have wide applications in dynamic monitoring and early warning of analytes in the various practical fields.

A facile approach for fabrication of three-dimensional platinum-nanoporous gold film and its application for sensitive detection of microRNA-126 combining with catalytic hairpin assembly reaction

MicroRNAs (miRNAs) as important biomarkers are closely related to cancers. Herein, a easy-facilitative nanocomposite which consists of Pt nanoparticles (PtNPs) and nanoporous gold (NPG) structure has been successfully prepared on Au electrode through a facile two-step square wave voltammetry (SWV) combining with electrodeposition method. Scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), and cyclic voltammetry (CV) were used for microscopic analysis and electrochemical studies of the PtNPs/NPG modified electrode. Combined with the well-designed catalytic hairpin assembly (CHA) amplification strategy, the small amount of Pt particles presented over the NPG film electrode substantially improved the electrocatalytic activity in the determination of microRNA-126 (miRNA-126), and a significant increase of amperometric current response accompanied with low background signal could be monitored at PtNPs/NPG electrode compared to those of bare Au and NPG electrodes. Under optimal conditions, a wide linear range of 0.5–500 pM for the amperometric assay of miRNA-126 was achieved along with a limit of detection (S/N = 3) of 0.17 pM. We further applied this assay to detect target miRNA in the total RNA extract of H1975 cells. Therefore, the proposed biosensing platform exhibits good analytical performance such as facile, ultrasensitive, low-cost, and high anti-interference capability, which promises to be a potential and beneficial tool for biomedical research and early clinical diagnosis of cancers through detection of multiple miRNA biomarkers.

The influence of dielectric permittivity of water on the shape of PtNPs synthesized in high-pressure high-temperature microwave reactor

In this paper, a novel method for the synthesis of Pt nanoparticles (PtNPs) using a microwave autoclave reactor is proposed. For benchmarking, the obtained results are compared with the traditional, batch method. A novel process window is proposed, which is the application of high-temperature and high-pressure. The main finding is that this only brings advantage, when the ionic strength of the system is enough low. It is explained, that at high pressure and high temperature, water behaves like only a slightly polar solvent, approaching a subcritical state. This reduces the electrostatic stabilization of the particles. Moreover, a change in the Pt particle shape is observed under high pressure and temperature conditions, suggesting that additional physical–chemical processes are involved.

Electrooxidation of 2-propanol on the mixture of nanoparticles of Pt and RuO2 supported on Ti

Abstract A thermal process was employed to prepare a catalyst consisting of a mixture of metallic-Pt and rutile RuO2 nanocrystals. This catalyst was used for the electrooxidation of 2-propanol in an alkaline solution. The effect of the catalyst composition on its microstructure, surface properties and catalytic activity was examined. With increasing the RuO2 content, the catalytic activity increases, reaches its maximum and then decreases. The catalytic effect is a result of the bifunctional mechanism of the mixture of Pt and RuO2 nanocrystals. The RuOHad particles are formed on Ru atoms of the RuO2 nanocrystals at potentials more negative than on Pt atoms. These oxy-species facilitate the dehydrogenation, breaking of C–C bonds and oxidation of both 2-propanol and its intermediates, adsorbed on assemblies of adjacent Pt atoms.

PtxCuy@TiO2 nanoparticles by low-pressure plasma synthesis

A new and original method is presented to synthesize Pt, Cu, and PtxCuy nanoparticles (NPs) anchored onto an inorganic nanopowder substrate (TiO2), based on the plasma degradation, within an Ar/NH3 radiofrequency plasma discharge, of solid organometallics (Cu and Pt acetylacetonate), mixed with TiO2. Both chemical and crystallographic characterizations confirm the formation of metastable alloyed Pt-Cu nanoparticles. The difference of Pt and Cu concentrations in NPs measured with a volume technique (X-ray diffraction) and a surface technique (X-ray photoelectron spectroscopy) suggests a Pt concentration gradient within NPs attributed to a difference in organometallics degradation kinetics.

Engineering sub-nano structures with highly jagged edges on the Pt surface of Pt/C electrocatalysts to promote oxygen reduction reactions

Improving the Pt mass activity (imPt) of electrocatalysts towards the oxygen reduction reactions requires an increase in Pt atom utilization efficiency. Through the combination of Cu underpotential deposition and Pt galvanic replacement (CuUPD-GAL), Pt nanoclusters (Ptcs<1 nm) with highly jagged edges (H-Ptcs) are specifically constructed on the Pt surface of a typical carbon-supported, Pt-nanoparticle (Pt/C) electrocatalyst. The H-Ptcs contribute to an imPt of 21.8 A mgPt−1 (at 0.9 V versus reversible hydrogen electrode), which exceeds that achieved by Pt/C (0.1–0.25 A mgPt−1) by a factor of 200. To facilitate a full-cell evaluation and to mimic the batch flow production of electrocatalysts, a sequential flow injection procedure is developed that enables the direct H-Ptcs modification on a commercial membrane electrode assembly (MEA), the heart of a fuel cell. In a full cell (real fuel cell), the contribution of the H-Ptcs to the current density of 3.5 A cm−2 at 0.7 V and maximum power density of 8.0 W cm−2 is higher than that of state-of-the-art Pt-containing catalysts (<1.5 A cm−2 and <1.4 W cm−2). A hybrid Ptc modification approach, in which an MEA is subjected to two sequential Ptc modification processes, improves the durability of the MEA while maximizing activity.

Synthesis of colloidal silver, platinum, and mixture of silver-platinum nanoparticles using pulsed laser ablation as contrast agent in computed tomography

Introduction : Over the last seven years, the development of nanoparticles as computed tomography (CT) contrast agents has increased significantly. In this present work, syntheses of colloidal silver nanoparticles (Ag NPs), platinum nanoparticles (Pt NPs), and silver-platinum nanoparticles (Ag-Pt NPs) have been successfully performed using pulsed laser ablation method in deionized water media.Materials and Methods : Experimentally, an neodymium-doped yttrium aluminum garnet (Nd:YAG) laser (1064 nm, 45 mJ, 10 Hz) was focused on a high-purity metal plate including Ag and Pt plates, which are placed in deionized water medium. Colloidal Ag NPs has been succesfully produced with a dark brownish-yellow color with an averaged diameter of 24 nm. For colloidal Pt NPs, the liquid has transparent color with an averaged diameter of 20 nm. Both colloidal nanoparticles of Ag and Pt were then mixed to obtain a mixture composition of Ag and Pt with ratios of Ag:Pt of 75:25%, 50:50%, 25:75%, respectively, with a concentration of each of 10 part per million (ppm). The Ag NPs, Pt NPs, and Ag-Pt NPs mixture were then examined as contrast agents in computed tomography (CT) scan. The CT Scan was set at 80 kV and 100 mAs. Results: The imaging results of these agents were measured in Hounsfield Unit (HU), showing 13.5, 12.8, 13.3, 14.1, and 17.3 HUs for colloidal Ag NPs only, colloidal Ag and Pt NPs with ratios of Ag:Pt of 75:25%, 50:50%, 25:75%, and colloidal Pt NPs only, respectively.Conclusion: These findings confirmed that for colloidal solution containing high concentration of platinum (Pt NPs only and colloidal Ag and Pt NPs with ratio of 25:75%) has higher HU values compared to the case of Pt NPs. The higher HU value for platinium can be attributed to its higher density.

Simultaneous wastewater treatment and generation of blended fuel methane and hydrogen using Au-Pt/TiO2 photo-reforming catalytic material

In this work, we report the generation of blended fuel of hydrogen and methane by using simultaneous photocatalysis and photoreforming reactions. A photocatalyst Au-Pt/TiO2 has been designed rationally and synthesized for the efficient electron transfer from Au to Pt and surface ensemble effects which improved the yield of hydrogen and methane. The distribution of Au and Pt nanoparticles were determined by using electron microscope investigations. The nanocatalyst was further studied for structural elucidation by using X-ray diffraction and optical spectroscopy. It was observed that the nanoparticles of Au and Pt dispersed on the TiO2 responsible for facilitation of electron transfer in UV and visible region. This mechanism easily excites TiO2 for catalytic transformation of carboxylic acid to hydrogen and methane. Under UV–Visible light (400 W) the newly developed catalyst reports effective production of hydrogen and methane at the rate of 9386 and 2208 µmol/h (14725 and 62579 µmol/h/g), respectively from acetic acid with apparent quantum yield of 3.85% at the bandgap of 3.2 eV. This catalytic production of hydrogen and methane (hythane gas) was examined using acetic acid enriched wastewater. The blended fuel obtained can be used in automobiles as the fuel with lower emissions compared with methane alone as the fuel.

Comparative Studies of CPEs Modified with Distinctive Metal Nanoparticle-Decorated Electroactive Polyimide for the Detection of UA.

In this present work, an electrochemical sensor was developed for the sensing of uric acid (UA). The sensor was based on a carbon paste electrode (CPE) modified with electroactive polyimide (EPI) synthesized using aniline tetramer (ACAT) decorated with reduced nanoparticles (NPs) of Au, Pt, and Ag. The initial step involved the preparation and characterization of ACAT. Subsequently, the ACAT-based EPI synthesis was performed by chemical imidization of its precursors 4,4′-(4.4′-isopropylidene-diphenoxy) bis (phthalic anhydride) BPADA and ACAT. Then, EPI was doped with distinctive particles of Ag, Pt and Au, and the doped EPIs were abbreviated as EPIS, EPIP and EPIG, respectively. Their structures were characterized by XRD, XPS, and TEM, and the electrochemical properties were determined by cyclic voltammetry and chronoamperometry. Among these evaluated sensors, EPI with Au NPs turned out the best with a sensitivity of 1.53 uA uM−1 UA, a low limit of detection (LOD) of 0.78 uM, and a linear detection range (LDR) of 5–50 uM UA at a low potential value of 310 mV. Additionally, differential pulse voltammetric (DPV) analysis showed that the EPIG sensor showed the best selectivity for a tertiary mixture of UA, dopamine (DA), and ascorbic acid (AA) as compared to EPIP and EPIS.

Kinetics of the reaction of H2 with Pt0-nanoparticles in aqueous suspensions monitored by the catalytic reduction of PW12O403−

The mechanism of the reaction between Pt0 nanoparticles and Hydrogen was measured in the absence of an electric field via following the formation of PW12O404−/5−.

H2 and CH4 production from bio-alcohols using condensed poly(heptazine imide) with visible light

Fully condensed poly(heptazine imide) (PHI) supported with highly dispersed Pt nanoparticles (PtNPs) achieves efficient and persistent H2 and CH4 production by photocatalytic reforming of biomass derived alcohols under visible light irradiation.

Electroless deposition of Pd/Pt nanoparticles on electrochemically grown TiO2 nanotubes for ppb level sensing of ethanol at room temperature.

This work presents a comparative sensing study of three sensors based on pristine TiO2 nanotubes, Pd loaded TiO2 nanotubes, and Pt loaded TiO2 nanotubes. Pristine TiO2 nanotubes were synthesized using an electrochemical anodization method and an electroless plating method was used for the uniform deposition of noble metal nanoparticles of either Pd or Pt over the surface of TiO2 nanotubes. The samples were thoroughly characterized by XRD, FESEM, EDS, TEM, and XPS techniques. The sensitivity of all three sensors was investigated at room temperature (300 K) for different volatile organic compounds like ethanol, methanol, 2-propanol, acetone, and benzene. The results revealed that loading of Pd and Pt nanoparticles improved the response magnitude of the sensor remarkably as these noble metals possess better oxygen dissociation capability than pristine TiO2. The Pd-TiO2 nanotube sensor exhibited a maximum response magnitude of 20-98% towards 100-1000 ppb of ethanol at room temperature. Notably, the formation of Pd/Pt-TiO2 discrete heterojunctions on the surface of TiO2 nanotubes was found to be responsible for enhanced sensitivity of the sensors.

Mediated Electrosynthesis and Catalytic Activity of Nanocomposites Formed by Metal Nanoparticles with Poly(N-vinylpyrrolidone) and Nanocellulose

Nanoparticles (NP) of Au, Ir, Pd, Pt, and Rh are synthesized by benzimidazo[1',2':1,2]quinolino-[4,3-b][1,2,5]oxodiazolo[3,4-f]quinoxaline (BIQOQ)-mediated electrochemical reduction of AuCl, K3[IrCl6], PdCl2, PtCl2, RhCl3, respectively, in the presence of poly(N-vinylpyrrolidone) (PVP) and nanocellulose (NC) at the potential controlled in the region of generation of BIQOQ.– anion radicals in the DMF/0.1 M Bu4NBF4 medium at room temperature. The efficiency of electrosynthesis is shown to be determined by the nature of the substrate to be reduced. K3[IrCl6] is virtually unreducible, whereas the other substrates are reduced to form NP–M. As the theoretical charge is passed, the generated metal is formed in the solution volume rather than as the cathodic deposit. NP–Au particles are formed in the quantitative amount, the mediator is retained in the process. In the other cases, the process consumes from ~50 (Ir, Pd, Pt) to 80% (Rh) of the mediator with the corresponding decrease in the NP–M yield. The synthesis produces individual spherical NP–Pd (4 ± 1 nm) and agglomerates of nanoparticles of gold (78 ± 27 nm), platinum (34 ± 14 nm), and rhodium (33 ± 20 nm) all stabilized in PVP shells. In contrast to the earlier described Ag@PVP nanoparticles which decorated NC in the extremely dense way, these particles are bound only partly with NC. The nanocomposites of Pd, Pt, and Au exhibit catalytic activity in the reactions of reduction of nitroaromatic compounds by sodium borohydride in aqueous media.

Laser-Induced Deposition of Plasmonic Ag and Pt Nanoparticles, and Periodic Arrays.

Surfaces functionalized with metal nanoparticles (NPs) are of great interest due to their wide potential applications in sensing, biomedicine, nanophotonics, etc. However, the precisely controllable decoration with plasmonic nanoparticles requires sophisticated techniques that are often multistep and complex. Here, we present a laser-induced deposition (LID) approach allowing for single-step surface decoration with NPs of controllable composition, morphology, and spatial distribution. The formation of Ag, Pt, and mixed Ag-Pt nanoparticles on a substrate surface was successfully demonstrated as a result of the LID process from commercially available precursors. The deposited nanoparticles were characterized with SEM, TEM, EDX, X-ray diffraction, and UV-VIS absorption spectroscopy, which confirmed the formation of crystalline nanoparticles of Pt (3–5 nm) and Ag (ca. 100 nm) with plasmonic properties. The advantageous features of the LID process allow us to demonstrate the spatially selective deposition of plasmonic NPs in a laser interference pattern, and thereby, the formation of periodic arrays of Ag NPs forming diffraction grating

Platinum nanoparticles/Ti3C2Tx (MXene) composite for the effectual electrochemical sensing of Bisphenol A in aqueous media

Abstract This paper evaluates the electrochemical performance of platinum nanoparticles/Ti3C2Tx nanocomposite (Pt@Ti3C2Tx) towards environmental sensing applications. The nanocomposite was prepared by self-reduction of Pt salt to Pt nanoparticles (PtNPs) on the surface of delaminated Ti3C2Tx nanosheets, in which Ti3C2Tx simultaneously acted as reducing agent as well as conductive matrix. The Pt@Ti3C2Tx nanocomposites with different Pt loading have been electrochemically characterized and it was found that 10%Pt@Ti3C2Tx has the highest electrochemical activity in the anodic potential window. Hence, 10%Pt@Ti3C2Tx has been used to develop an electrochemical sensor for the detection of Bisphenol A (BPA), which is one of the common environmental pollutants. At the optimal conditions, the oxidation peak of BPA was proportional to the analyte concentration from 50 nM to 5 μM with a detection limit of 32 nM. The practical application of the proposed sensor was successfully evaluated in drinking water and fresh milk samples.