Palladium monolayer-protected clusters (MPCs) coated with octylamines (C8NH2), hexanethiolates (C6S), and mixed monolayers of C8NH2 C6S exhibit significantly different reactivities hydrogen gas, depending on the relative amounts two ligands coating Pd nanoparticle surface, as determined by UV−vis spectroscopy MPCs in solution electronic measurements films a function exposure time to hydrogen. The average estimated composition ∼3.0 nm diameter was Pd919(C6S)192 or Pd919(C8NH2)177−x(C6S)x,...

Here we describe the chemiresistive sensing of volatile organic compounds (VOCs) with films chemically synthesized ∼4 nm diameter Au and AuAg alloy nanoparticles (NPs) stabilized by a surfactant, tetraoctylammonium bromide (TOABr). The properties were measured over concentration range 100 to 0.04% saturation for methanol (MeOH), ethanol (EtOH), 2-propanol (IPA), toluene (Tol) vapor analytes compared directly 1.6 hexanethiolate (C6S)-coated monolayer-protected clusters (MPCs). Films...

Hydrogen gas spontaneously adsorbs to Pd metal as atomic hydrogen and diffuses into the lattice form PdHx. We previously showed that films of hexanethiolate-coated monolayer-protected clusters (MPCs) do not readily react with H2 due strong chemical bonding thiolate Pd, which inhibits reaction. Consequently, these require ozone or heat treatment for reactivity occur, is inconvenient sensing catalysis applications. In this report, we describe between solid-state alkylamine-coated PdAg (10:1),...

Here we describe the chemiresistive H2-sensing properties of drop-cast films comprised 3.0 nm average diameter hexanethiolate-coated Pd monolayer-protected clusters (C6 MPCs) bridging a pair electrodes separated by 23 microm gap. The gas-sensing were measured for 9.6-0.11% H2 in H2/N2 mixture. sensing mechanism is based on changes resistance film upon reaction with to form PdH(x), which known be larger volume and more resistive than pure Pd. As-prepared MPC are highly insensitive H2,...

The layer stacking morphology in nanocarbons is paramount for achieving new properties and outperforming applications. Here, we demonstrate that graphene quantum dots (GQDs) retain crystallinity a structure from CVD grown on Ni foam. Our results reveal GQD subdomains comprise few-layer the AB···AB ABC···ABC configuration. HR-TEM images along with multiple-approach characterization (XRD, XPS, UV–vis, AFM, ATR-IR) exhibit ∼3.0 to ∼8.0 nm crystalline GQDs 2–6 layers thick indicating disk-shape...

In this work, we observe a template-free formation of nanowires (NWs) during electrophoretic deposition (EPD) chemically synthesized core-shell Ag-graphene quantum dots (GQDs) hybrid nanoparticles (hNPs) with diameter ∼20 nm. The EPD method consists transparent ITO-glass electrode subjected to 1.0 V (vs SCE) and immersed in as-synthesized hNPs aqueous dispersion containing hydroquinone (HQ). During EPD, Ag-GQDs tend align close each other ultimately form well-connected NWs comprised ∼5.6 μm...

This work explores size transformations during the electrophoretic deposition (EPD) of citrate-coated Au nanoparticles (NPs). The EPD method involves a transparent ITO-glass electrode subjected to 1.0 V (vs Ag/AgCl) immersed in solution as-synthesized NPs with hydroquinone (HQ) serving for NPs. We observed that monodisperse 6.0 nm average diameter became polydisperse within first 300 s EPD, forming two well-defined sizes (∼5.0 and 10 nm), as determined by AFM anodic stripping voltammetry...

Here, we developed a simple method for obtaining heterojunction composed of graphene (G) and surfactant-coated Au nanoparticles (NPs) to measure film conductivity surface enhanced Raman scattering (SERS). Monolayer G is obtained by chemical vapor deposition (CVD) transferred via poly(methyl methacrylate) (PMMA) microfabricated electrodes, glass, silicon. Post-synthesis treatments with PMMA ozone (O3) showed 1 6 orders magnitude decrease in conductivity, respectively. The formation NPs had no...

A computational laboratory experiment is carried out to investigate the size-, geometry-, and chemistry-dependent properties of small molecules known as polycyclic aromatic hydrocarbons (PAHs) at Facultad de Ingeniería (Universidad Nacional La Plata, UNLP), Buenos Aires, Argentina. This research was adapted for upper-division undergraduate initial graduate education levels. Due adverse circumstances pandemic, students were challenged perform theoretical calculations on a regular computer...

Herein, we report the synthesis of graphene quantum dots (GQDs) functionalized with 1,5-diphenylcarbazone for selective quantification Fe in wine, via front-face fluorescence.Crystalline GQDs are obtained a clean and relatively size-controlled based on electrochemical exfoliation from foam.The product was later to solely detect 3+ amongst various other ions present within sample.The detection is quenching fluorescence emission nanomaterial presence analyte, which follows linear relationship...

Here we report the stability, conductivity, and vapor-sensing properties of microcontact-printed films 1.6-nm average diameter hexanethiolate-coated gold monolayer protected clusters (C6 Au MPCs). The C6 MPCs were stamped into parallel lines (approximately 1.2 microm wide 400 nm thick) across two electrodes separated by a 1-microm gap. chemiresistive measured for saturated toluene 2-propanol vapors. As-prepared patterned MPC unstable in presence vapor, their current response was...

Here, we report the use of tetraoctylammonium bromide (TOABr)-coated Au nanoparticles (NPs) for optical sensing volatile organic compounds (VOCs). We find that film responded selectively to presence polar and nonpolar vapors by changes in maximum wavelength (λ(max)) toward higher lower wavelengths, respectively, as determined UV-visible spectroscopy. also observed coating reorganizes when partition into indicated FT-IR contracts water scanning electron microscopy (SEM). In present sensor,...

A combination of chemically functionalized-graphene quantum dots with a machine learning algorithm permits selectivity and accurate detection Fe 3+ Hg 2+ ions in real water samples.

The growth of graphene on an irregular three-dimensional (3D) Ni structure is demonstrated to be interesting platform for molecular sensing, graphene-enhanced Raman scattering, and surface-enhanced scattering (SERS) applications after galvanic exchange Ag+ ions. Raman, scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDX), optical images, diffuse reflectance demonstrate that grows in a multilayer fashion with different stacking configurations. Statistics performed...

The way graphene (GDs) and carbon dots (CDs) are synthesized combined with TiO2 determine their photoelectrochemical efficiency upon UV visible LED lights. GDs CDs obtained by relatively unexplored top-down methods conventional bottom-up methods, respectively. Top-down consist in the seedless growth of ZnO nanoparticles on surface electrochemical cleavage grown Ni foam. These later different approaches such as solution mixing, adsorption via APTES linkers, drop-casting an already formed...

Here we explore the synthesis of alkanethiol-coated Ni NPs following one-phase reaction method by Brust et al.(1) The reduction NiCl2 with NaBH4 in presence dodecanethiol (C12SH) yields a complex product that is difficult to identify as illustrated figure merit. We synthesized Ni(II) dodecanethiolate (C12S) (without addition NaBH4) for comparison and performed an exhaustive characterization TEM, HR-TEM, AFM, MFM, XPS, XRD, UV–vis, magnetism, FT-IR. It found organic coating not quite...

The synergy between graphene foam (Gf) and ZnO nanoparticles (NPs) allows the detection of analytes at low conentrations, which can be subsequently photocatalyzed on hybrid surface as well in liquid phase upon illumination with low-power UV–vis light-emitting diode (LED) lamps. Detection methylene blue (MB) bisphenol A (BPA) is monitored either by graphene-enhanced Raman scattering (GERS) or molecular doping/sensing analyte adsorption. Using GERS, we were able to detect concentrations 0.3...

Transferring CVD graphene using surfactant-protected Au nanoparticles (Au NPs) avoids the use of PMMA and opens new ways building heterojunctions for TERS SERS applications. Thermal treatment removes organics from NPs leads to larger formation networks, dimmers, nanoplates various shapes (circles, hexagons, triangles). Raman HRTEM revealed bilayer Moiré patterns as determined by 2D band dislocated atomic layers, respectively. performed on heterojunction exhibits a reversible increase in...

We explore into the role of organic ligands composition surrounding Au nanoparticles (NPs) toward internanoparticles distance changes and film structure during vapor sensing by use in situ grazing-incidence small-angle X-ray scattering (GISAXS) other relevant techniques. observed distinct core-to-core upon measured concentrations polar ethanol (EtOH) nonpolar toluene (Tol) vapors. As-formed tetraoctylammonium bromide (TOABr)-coated NPs (SNPs) exhibited ∼0.4 nm increase improved SNPs...

Summary Switching between different therapeutic FVIII concentrate types has been postulated as a possible cause of inhibitor development in patient with haemophilia A. In this single‐centre, retrospective study, the incidence, titre and duration multitransfused patients, defined patients more than 150 exposure days ( ED ), were analysed from January 1970 to December 2007 relation number switches products. Inhibitor was assessed by Bethesda assay (before 1998) or Nijmegen (after 1998)....

ZnO nanostructures were obtained by electrodeposition on Ni foam, where graphene was previously grown chemical vapor deposition (CVD). The resulting heterostructures characterized X-ray diffraction and SEM microscopy, their potential application as a catalyst for the photodegradation of methylene blue (MB) evaluated. incorporation to substrate increases amount deposited at low potentials in comparison bare Ni. images show homogeneous growth Ni/G but not foam. A percent removal almost 60% MB...