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Modulation of the electronic structure of metal-based catalysts proves to be useful for optimizing the catalytic activity. However, precise modulation of the electronic structure at the atomic scale remains challenging, because of the invariant electronic structure of single atoms and the difficulty in achieving the size limit for tailored alloy particles. Herein, we report a RuCo single-atom alloy (SAA) catalyst with precisely tailored electron-rich Ru atoms confined into the Co lattice, skillfully fabricated by pyrolysis of Ru-containing ZIF-67 with a tuned Ru feed content. The structure of RuCo SAAs is well investigated by various characterization techniques, including aberration-corrected scanning transmission electron microscopy, high-energy X-ray diffraction, X-ray photoelectron spectroscopy, and X-ray absorption fine structure. It is found that the RuCo SAAs with more electron-rich Ru atoms are more active toward aqueous levulinic acid (LA) hydrogenation to γ-valerolactone, delivering an extremely large turnover frequency value of 3500 h–1, 27 fold higher than that over the state-of-art 5 wt % Ru/C catalyst and much higher than those over electron-deficient Ru single atoms and Ru-containing alloyed particles. Combined experimental investigation and computational modeling reveal that the remarkable activity originates from the intrinsic RuCo SAA active site in which the electron-rich Ru single-atom boosts CO/H2 adsorption and H2 dissociation to H atoms and especially facilitates the γ-C of LA hydrogenation, which is the rate-determining step for LA hydrogenation. This study will shed light on the precise tailoring of the electronic structure at the atomic scale and also provides insight into the development of SAA catalysts for biomass conversion.

As a first step of the EXL project scheduled for the New Experimental Storage Ring at FAIR a precursor experiment (E105) was performed at the ESR at GSI. For this experiment, an innovative differential pumping concept, originally proposed for the EXL recoil detector ESPA, was successfully applied. The implementation and essential features of this novel technical concept will be discussed, as well as details on the detectors and the infrastructure around the internal gas-jet target. With 56 Ni(p, p) 56 Ni elastic scattering at 400 MeV u −1 , a nuclear reaction experiment with stored radioactive beams was realized for the first time. Finally, perspectives for a next-generation EXL-type setup are briefly discussed.

Supporting information 1. CharacterizationPowder X-ray diffraction (PXRD) measurements were performed using a Rigaku D/MAX-2500 X-ray diffractometer with CuKa radiation. Samples were analyzed over a range of 2θ=1.5-10° using a step scan mode with a step rate of 1°/min. Scanning electron microscopy (SEM) measurements and X-ray electron spectroscopy (EDS)

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In this work, the effect of doubly functionalized montmorillonite (MMT) on the structure, morphology, thermal, and tribological characteristics of the resulting polystyrene (PS) nanocomposites was investigated. The modification of the MMT was performed using a cationic surfactant and an anionic surfactant or a silane coupling agent to increase the compatibility with PS matrix. The polystyrene/organo-montmorillonite (PS/OMMT) nanocomposite particles were prepared by soap-free emulsion polymerization. The OMMT was studied using Fourier-transform infrared (FTIR), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). The structural and morphological changes of PS/OMMT nanocomposites were further characterized by dynamic light scattering (DLS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The thermal stability of all the PS/OMMT nanocomposites was higher than that of the pure PS. The anti-wear properties of the polyalphaolefin (PAO) were significantly improved due to the introduction of the PS/OMMT nanocomposite particles. The nanocomposites prepared by a cationic surfactant and a silane coupling agent exhibited the best thermal stability and tribological performance. Our results provide the valuable insights needed to guide the design of lubrication and friction reducing materials.

The absolute differential cross section for small-angle proton elastic scattering on the proton-rich 8 B nucleus has been measured in inverse kinematics for the first time. The experiment was performed using a secondary radioactive beam with an energy of 0.7 GeV/u at GSI, Darmstadt. The active target, namely hydrogenfilled time projection ionization chamber IKAR, was used to measure the energy, angle and vertex point of the recoil protons. The scattering angle of the projectiles was simultaneously determined by the tracking detectors. The measured differential cross section is analyzed on the basis of the Glauber multiple scattering theory using phenomenological nuclear-density distributions with two free parameters. The radial density distribution deduced for 8 B exhibits a halo structure with the root-mean-square (rms) matter radius R m = 2.58(6) fm and the rms halo radius R h = 4.24(25) fm. The results on 8 B are compared to those on the mirror nucleus 8 Li investigated earlier by the same method. A comparison is also made with previous experimental results and theoretical predictions for both nuclei.