Improving the HER activity and stability of Pt nanoparticles by titanium oxynitride support

Water electrolysis powered by renewables is regarded as the feasible route for the production of hydrogen, obtained at the cathode side through electrochemical hydrogen evolution reaction (HER). Herein, we present a rational strategy to improve the overall HER catalytic performance of Pt, which is known as the best monometallic catalyst for this reaction, by supporting it on a conductive titanium oxynitride (TiON$_x$) dispersed over reduced graphene oxide nanoribbons. Characterization of the Pt/TiON$_x$ composite revealed the presence of small Pt particles with diameters between 2 and 3 nm, which are well dispersed over the TiON$_x$ support. The Pt/TiON$_x$ nanocomposite exhibited improved HER activity and stability with respect to the Pt/C benchmark in an acid electrolyte, which was ascribed to the strong metal−support interaction (SMSI) triggered between the TiON$_x$ support and grafted Pt nanoparticles. SMSI between TiON$_x$ and Pt was evidenced by X-ray photoelectron spectroscopy (XPS) through a shift of the binding energies of the characteristic Pt 4f photoelectron lines with respect to Pt/C. Density functional theory (DFT) calculations confirmed the strong interaction between Pt nanoparticles and the TiON$_x$ support. This strong interaction improves the stability of Pt nanoparticles and weakens the binding of chemisorbed H atoms thereon. Both of these effects may result in enhanced HER activity

Reliability and cost of GMO detection

Chapitre 18International audienceThe analytical procedure used for GM detection and quantification at the laboratory level is composed of different modules. Each module can qualitatively and/or quantitatively impact the accuracy of the analytical result. Within the Co-Extra project, we have investigated different aspects of reliability of GMO detection. We have also established a system for improving reliability of quantitative analysis in samples with low DNA content. Additionally, we present and discuss efforts to reducethe trade-off between reliability and analysis costs

Comment on the letter of the Society of Vertebrate Paleontology (SVP) dated April 21, 2020 regarding “Fossils from conflict zones and reproducibility of fossil-based scientific data”: the importance of private collections

International audienc