Hexacyano Ferrate (III) Reduction by Electron Transfer Induced by Plasmonic Catalysis on Gold Nanoparticles

International audienc

Plasmonic catalysis for the Suzuki–Miyaura cross-coupling reaction using palladium nanoflowers

International audienc

Gold(I)-Silver(I)-calix[8]arene complexes, precursors of bimetallic alloyed Au-Ag nanoparticles

International audienceIn this paper, we report the first synthesis and characterisations of bimetallic gold(I)–silver(I) calix[8]arene complexes. We show that the radiolytic reduction of these complexes leads to the formation of small bimetallic nanoparticles with an alloyed structure, as evidenced by XPS, HR-TEM and STEM/HAADF-EDX measurements

Polypyrrole nanostructures modified with mono- and bimetallic nanoparticles for photocatalytic H 2 generation

International audienc

A Facile One-Pot Synthesis of Versatile PEGylated Platinum Nanoflowers and Their Application in Radiation Therapy

International audienceNanomedicine has stepped into the spotlight of radiation therapy over the last two decades. Nanoparticles (NPs), especially metallic NPs, can potentiate radiotherapy by specific accumulation into tumors, thus enhancing the efficacy while alleviating the toxicity of radiotherapy. Water radiolysis is a simple, fast and environmentally-friendly method to prepare highly controllable metallic nanoparticles in large scale. In this study, we used this method to prepare biocompatible PEGylated (with Poly(Ethylene Glycol) diamine) platinum nanoflowers (Pt NFs). These nanoagents provide unique surface chemistry, which allows functionalization with various molecules such as fluorescent markers, drugs or radionuclides. The Pt NFs were produced with a controlled aggregation of small Pt subunits through a combination of grafted polymers and radiation-induced polymer cross-linking. Confocal microscopy and fluorescence lifetime imaging microscopy revealed that Pt NFs were localized in the cytoplasm of cervical cancer cells (HeLa) but not in the nucleus. Clonogenic assays revealed that Pt NFs amplify the gamma rays induced killing of HeLa cells with a sensitizing enhancement ratio (SER) of 23%, thus making them promising candidates for future cancer radiation therapy. Furthermore, the efficiency of Pt NFs to induce nanoscopic biomolecular damage by interacting with gamma rays, was evaluated using plasmids as molecular probe. These findings show that the Pt NFs are efficient nano-radio-enhancers. Finally, these NFs could be used to improve not only the performances of radiation therapy treatments but also drug delivery and/or diagnosis when functionalized with various molecules

Superior photocatalytic activity of polypyrrole nanostructures prepared by radiolysis in water and dichloromethane

International audienceConjugated polymers have emerged as very active photocatalysts under visible light. Among these materials, nanostructured polypyrrole (PPy) has recently been used as photocatalyst for degradation of environmental pollutants under UV as well as visible light. In the present study, we specifically explored the photocatalytic activity of conducting PPy synthesized by radiolysis, either in water (PPyH2O) or in dichloromethane solvent (PPyDCM), in the absence of any external dopant or template. The successful preparation of both kinds of conducting polymers was confirmed by complementary spectroscopic techniques and morphological characterizations. Besides, the photocatalytic activity of both materials was evaluated in the degradation of phenol as model pollutant in aqueous solution. PPyH2O as well as PPyDCM were found to exhibit remarkably high photocatalytic activity under both UV and visible light. These organic photocatalysts remain very stable after several cycles and thus, easily reusable. Interestingly, PPyDCM clearly appears as the most efficient photocatalyst due to its longer chain length, highly doped nature, lower optical band gap and extended absorption band from the UV to the near infrared region. The present work definitely validates radiation chemistry as an 2 alternative approach to synthesize conducting polymer-based photocatalysts. The obtained results also highlight that the radiosynthesized PPy, especially those prepared in dichloromethane, constitute promising candidates for photocatalytic depollution of water

Highly active composite TiO2-polypyrrole nanostructures for water and air depollution under visible light irradiation

International audienc

Photocatalytic Hydrogen Evolution Using Ni–Pd/TiO 2 : Correlation of Light Absorption, Charge-Carrier Dynamics, and Quantum Efficiency

International audienceTiO2 surface modification with bimetallic nano particles (NPs) has demonstrated to be a strategy to enhance the hydrogen generation via photocatalysis and to minimize the use of expensive noble metals. A better understanding of the role of bimetallic NPs is of crucial importance to design efficient photocatalysts. Here, we show a systematic study of surface modification of commercial TiO2 (P25) with mono and bimetallic (Ni, Pd, and Ni-Pd) NPs synthesized by radiolysis. The photocatalysts were characterized by High Resolution Transmission Microscopy (HRTEM), Scanning Transmission Electron Microscope (STEM), X-ray Diffraction (XRD), Energy-Dispersive X-ray Spectroscopy (EDS), X-ray Photoelectron Spectroscopy (XPS), and UV-vis Diffuse Reflectance Spectroscopy (DRS). The charge-carrier dynamics was studied by Time Resolved Microwave Conductivity (TRMC). The photocatalytic activity was evaluated for hydrogen generation under UV-vis irradiation using polychromatic and monochromatic lights (action spectra analysis of apparent quantum efficiency). TiO2 modified with Pd-Ni bimetallic NPs exhibits a high activity for H-2 generation, and a synergetic effect of the two metals was obtained. The study of light absorption, charge-carrier dynamics, and photocatalytic activity revealed that the main role of the metal NPs is to act as catalytic sites for recombination of atomic hydrogen