Characterization Of Platinum Nanoparticles Research Articles

Enhancing Intrinsic Electrocatalytic Activity of Pt/C Nanoparticles for Oxygen Reduction Reaction in Acidic Media by Microwave-Assisted Synthesis

Abstract: This study is focused on the enhancement of the intrinsic electrocatalytic activity of Pt nano-particles supported on C (Pt/C NPs) towards Oxygen Reduction Reaction (ORR) in acidic media. The goal was to investigate the effect of microwave-assisted synthesis on the electrocatalytic performance of Pt/C NPs towards ORR. Thus, Pt/C NPs were synthesized using a microwave-assisted method and by a conventional heating method; structural and morphological characteristics were analyzed by X-ray dif-fraction (XRD) and transmission electron microscopy (TEM). Electrochemical studies were performed using the rotating disk electrode technique to evaluate the ORR performance. Microwave-assisted syn-thesis produced Pt/C NPs with a smaller particle size (6.3 ± 0.2 nm) than conventionally synthesized nanoparticles (8.6 ± 0.3 nm). Electrochemical analysis showed that the microwave-synthesized Pt/C NPs exhibited higher mass activity (4.6 ± 0.8 mA･g-1Pt) for ORR compared to conventionally synthesized nanoparticles (1.9 ± 0.4 mA･mA･g-1Pt). These results demonstrate that microwave-assisted synthesis en-hances the intrinsic electrocatalytic activity of Pt/C NPs for ORR in acidic media. These findings have important implications for the development of efficient electrocatalysts for fuel cell applications. Background: The synthesis and characterization of platinum nanoparticles on C are crucial for advancing electrocatalysis, particularly in the context of potential applications in fuel cells. This study builds on previous research, focusing on two distinct synthesis methods to enhance our understanding of their im-pact on nanoparticle properties and electrocatalytic performance. Objective: To investigate the synthesis efficiency, structural characteristics, and electrocatalytic activities of platinum nanoparticles on C using microwave-assisted heating and conventional synthesis reactor heating. The objective is to discern any significant differences in particle size, structure, and electrocata-lytic performance between the two synthesis methods. Methods: The synthesis involved a comparative analysis of platinum nanoparticles using microwave-assisted and conventional heating methods. Chemical composition analysis verified the synthesis efficiency, and structural and morphological characterizations were performed using X-ray Diffraction and Transmission Electron Microscopy. Electrochemical studies employed the rotating disk electrode technique, with activation and evaluation conducted through cyclic voltammetry, and the oxygen reduction reaction studied via linear sweep voltammetry in an acidic media (0.5 mol⋅L-1 H2SO4). Results: Well-supported platinum nanoparticles with a face-centered cubic structure were obtained on C using both synthesis methods. However, microwave-synthesized particles (6.3 ± 0.2 nm) exhibited a smaller size compared to conventionally synthesized particles (8.6 ± 0.3 nm). Electrochemical assess-ment revealed superior mass activity for microwave-synthesized material (4.6 ± 0.8 mA･g-1Pt), outper-forming commercial Pt nanoparticles (3.0 ± 0.3 mA･g-1Pt) and conventionally synthesized material (1.9 ± 0.4 mA･mA･g-1Pt). Conclusion: This study concludes that microwave-assisted synthesis yields platinum nanoparticles on C with enhanced electrocatalytic performance, as evidenced by the smaller particle size and superior mass activity compared to conventionally synthesized material and commercial Pt nanoparticles. These findings highlight the potential of microwave-synthesized Pt nanoparticles for applications in fuel cells.

Quantitative analysis and characterization of PtNPs in road dust based on ultrasonic probe assisted extraction and single particle inductively coupled plasma mass spectrometry

As a result of their growing use, platinum nanoparticles (PtNPs) can pollute different environmental compartments, especially road dust due to their application in vehicle catalytic converters. Their presence in these matrices should be controlled to achieve adequate environmental risk assessment, but there is a lack of standardized analytical methods for this purpose. Therefore, this study describes the development and analytical characterization of a rapid sample preparation strategy for the analysis of PtNPs in road dust by single particle inductively coupled plasma mass spectrometry (SP-ICP-MS). Parameters within the critical steps of the extraction (such as the type of energy, sample-to-reagent ratio, intensity, or time), and subsequent phase separation have been optimized using a road dust reference material (BCR-723, certified for total Pt), and spiked road dust samples. The final method consists of a sonication probe assisted extraction, using water as extractant, followed by a separation based on centrifugation, and dilution prior to SP-ICP-MS. Information about size and both mass- and particle-based concentration is provided in <11 min. A recovery rate of 100 ± 1% is achieved in the spiked road dust samples, and a 12 ± 1% (n = 6) of the total Pt was found to be as PtNPs in the certified reference material. The applicability of this methodology has been proven performing the analysis of PtNPs in real road dust samples, with sizes between 15 and 75 nm, and concentrations (6.0–20.0 ng g−1) that represents from 11 to 27% of the Pt content.

Synthesis and Spectroscopic Characterization of Platinum Nanoparticles by Plasma Jet Method

In this research, Argon gas was used to generate atmospheric plasma in the manufacture of platinum nanomaterials, to study the resultant plasma spectrum and to calculate the cellular toxicity of those manufactured nanomaterials. This research is keen on the generation of nonthermal atmospheric pressure plasma using aqueous platinum salts (H2PtCl6 6H2O) with different concentrations and exposure of cold plasma with a different time period used to produce platinum nanoparticles, to ensure typical preparation of nanoparticles. Visible UV and X-rays were performed for this purpose, and the diameter of the system probe was (1[Formula: see text]mm) with the Argon gas flow of 2.5[Formula: see text]min/L to prepare the platinum nanoparticles, and spectroscopic study of plasma parameter including, electron temperature, electron density, Debye length and plasma frequency, were computed using spectral analysis techniques. The effect of nanoparticles on natural lymphocytes was studied to calculate cytotoxicity and the greatest proportion was at the concentration of 100% nanoparticle platinum is 37.4%. The study results revealed that cold in the atmosphere is a promising technology when used in the production of nanoparticle materials which can be used for many industrial and medical applications.

Biosynthesis and characterization of platinum nanoparticles using Iraqi Zahidi dates and evaluation of their biological applications

Platinum nanoparticles (Pt NPs) were synthesized by utilizing the Zahidi dates extract by green synthesis technique. Platinum salts were successfully reduced to their corresponding Pt NPs in the presence of aqueous dates extract which considers a rich source of phytochemicals that led to the reduction of Pt+4 to Pt° atoms by providing electrons for these ions. Many techniques characterized the nanoparticles. TEM analysis showed that the Pt NPs were exhibited in diameters ranging from (30−45) nm. FE-SEM images display nanoparticles in spherical shapes. AFM screening shows that Platinum nanoparticles had small size distribution. XRD diffraction examination showed that the formation of Platinum nanoparticles exhibits a face centred cubic crystalline structure by spectrum comparative to the standard confirmed spectrum of Platinum particles produced in the experiments were in the shape of nanocrystals. The fourier transform infrared spectroscopy spectrum showed various peaks ranging from (400–4000) cm−1 used to identify the functional groups responsible for reducing and capping of Pt NPs. Cancer cells including the ovarian cancer SKO-3 cell line and Oesophageal cancer SK-GT-4 cell line were exposed to a series of prepared Platinum nanoparticle concentrations (0.00125, 0.0025, 0.005, 0.01) M, and the inhibition rate of growth in cells was measured for 72 h. The cytotoxicity screening showed that there was a highly toxic effect on the cancer cells. Gram-negative bacterial strain Pseudomonas aeruginosa and Gram-positive bacterial strain Streptococcus pyogenes were exposed to a series of concentrations from prepared Platinum nanoparticles (0.00125, 0.0025, 0.005, 0.01) M. The results exhibited significant inhibitory activity and the rate of bacterial growth inhibition increased with increasing concentration.

Photoactive Dendrimer for Water Photoreduction: A Scaffold to Combine Sensitizers and Catalysts.

We report on the synthesis and characterization of platinum nanoparticles (PtNps) inside the cavities of a PAMAM dendrimer decorated with [Ru(bpy)3](2+) units at the periphery. The phosphorescent ruthenium complexes are used as signaling units of the Pt(2+) complexation in the dendritic architecture and as photosensitizer units in the photocatalytic production of H2 from water. This is the first example of water photoreduction in which the catalyst and the sensitizer are anchored on a dendritic molecular scaffold. This study provides a new outlook in the design of new supramolecular systems and materials for developing artificial photosynthesis.

Synthesis and Characterization of Platinum Nanoparticles on PT-Coated Mesoporous Silica as an Electrocatalyst for Direct Methanol Fuel Cells

Nanoparticles of mesoporous silica are synthesized and modified by Poly-thiophene (PT) to improve the electrical conductivity. Platinum nanoparticles are synthesized and deposited on the surface of the modified mesoporous silica. The materials in each step are well characterized by X-ray powder diffraction, high resolution transmission electronic microscopy, thermal analysis (TGA/DTA), nitrogen sorption analysis, elemental analysis (CHNS), inductive coupled plasma and optical emission spectroscopy. This composite is used as an anodic electrocatalyst for direct methanol fuel cell application. The influence of loading of the electrocatalyst and temperature on the performance of a direct methanol fuel cell is studied and the results are discussed. A maximum power density of 35.96 mW cm−2 at a current density of 129.44 mA cm−2 was obtained, which is attributed to the dispersion and accessibility of the modified mesoporous silica support in the electrocatalyst mixture for the methanol oxidation reaction.

Synthesis and characterization of platinum nanoparticles on carbon nanosheets with enhanced electrocatalytic activity toward methanol oxidation

This report describes carbon nanosheets (CNSs) were employed as a catalyst support for loading platinum nanoparticles (Pt NPs) by one-step electrodeposition. The structure, size, and chemical composition of the CNS-supported Pt NPs (Pt/CNSs) were characterized by scanning and transmission electron microscopies, energy dispersive X-ray and X-ray photoelectron spectroscopies. The electrocatalytic performances of the Pt/CNSs for methanol oxidation have been investigated by cycle votammetry and chronoamperometry. These results demonstrated the Pt/CNSs possess high electrocatalytic activity and excellent stability due to high dispersion of Pt NPs on the CNS surface and the special nature properties of CNSs. The Pt/CNSs should be a promising electrocatalyst in direct methanol fuel cells.

The synthesis and characterization of platinum nanoparticles: a method of controlling thesize and morphology

In this paper, Pt nanoparticles with good shapes of nanocubes and nano-octahedraand well-controlled sizes in the range 5–7 and 8–12 nm, respectively, havebeen successfully synthesized. The modified polyol method by adding silvernitrate and varying the molar ratio of the solutions of silver nitrate andH2PtCl6 has been used to produce Pt nanoparticles of the size and shape to be controlled. The sizeand morphology of Pt nanoparticles have been studied by transmission electron microscopy(TEM) and high resolution TEM (HRTEM). The results have shown that their very sharpand good shapes exist in the main forms of cubic, cuboctahedral, octahedral andtetrahedral shapes directly related to the crystal nucleation along various directions of the{100} cubic,{111} octahedraland {111} tetrahedral facets during synthesis. In particular, various irregular and new shapes of Ptnanoparticles have been found. Here, it is concluded that the role of silver ions has to be consideredas an important factor for promoting and controlling the development of Pt nanoparticles of{100} cubic,{111} octahedraland {111} tetrahedral facets, and also directly orienting the growth and formation of Ptnanoparticles.

Synthesis and characterization of platinum nanoparticles on single-walled Carbon nanotube "nanopaper" support

We prepared several samples of carbon-nanotube-supported Pt nanoparticles that are potentially promising electrocatalysts for hydrogen fuel cells. Commercially obtained single-walled carbon nanotubes (SWNTs) were characterized by Raman Spectroscopy, SEM, TEM, EDS, and XANES. This multi-technique characterization allowed us to quantify the size and composition of metal impurities (Mo, Co) in SWNTs, to choose the best method to remove them, and characterize the effectiveness of their removal. After synthesizing a "nanopaper" (10–20 micrometer thick, free standing sheets of self-assembled SWNTs) we decorated it with Pt nanoparticles by electroless deposition. Formation of Pt nanoparticles was verified by EXAFS, and quantitative information about their size and structure was obtained.

Synthesis and characterization of platinum nanoparticles on in situ grown carbon nanotubes based carbon paper for proton exchange membrane fuel cell cathode

Multi-walled carbon nanotubes (MWCNTs) based micro-porous layer on the carbon paper substrates was prepared by in situ growth in a chemical vapor deposition setup. Platinum nanoparticles were deposited on in situ grown MWCNTs/carbon paper by a wet chemistry route at <100 °C. The in situ MWCNTs/carbon paper was initially surface modified by silane derivative to incorporate sulfonic acid–silicate intermediate groups which act as anchors for metal ions. Platinum nanoparticles deposition on the in situ MWCNTs/carbon paper was carried out by reducing platinum (II) acetylacetonate precursor using glacial acetic acid. High resolution TEM images showed that the platinum particles are homogeneously distributed on the outer surface of MWCNTs with a size range of 1–2 nm. The Pt/MWCNTs/carbon paper electrode with a loading of 0.3 and 0.5 mg Pt cm −2 was evaluated in proton exchange membrane single cell fuel cell using H 2/O 2. The single cells exhibited a peak power density of 600 and 800 mW cm −2 with catalyst loadings of 0.3 and 0.5 mg Pt cm −2, respectively with H 2/O 2 at 80 °C, using Nafion-212 electrolyte. In order to understand the intrinsically higher fuel cell performance, the electrochemically active surface area was estimated by the cyclic voltammetry of the Pt/MWCNTs/carbon paper.