Coordinatively unsaturated ferrous (CUF) sites confined in nanosized matrices are active centers in a wide range of enzyme and homogeneous catalytic reactions. Preparation of the analogous active sites at supported catalysts is of great importance in heterogeneous catalysis but remains a challenge. On the basis of surface science measurements and density functional calculations, we show that the interface confinement effect can be used to stabilize the CUF sites by taking advantage of strong adhesion between ferrous oxides and metal substrates. The interface-confined CUF sites together with the metal supports are active for dioxygen activation, producing reactive dissociated oxygen atoms. We show that the structural ensemble was highly efficient for carbon monoxide oxidation at low temperature under typical operating conditions of a proton-exchange membrane fuel cell.

Liver enzyme abnormalities in patients with COVID-19 are associated with disease severity. Patients with liver enzyme abnormalities have higher A-aDO2 and GGT, lower albumin and decreased circulating CD4+ T cells and B lymphocytes. SARS-CoV-2 is able to infect the liver and cause conspicuous hepatic cytopathy. Massive apoptosis and binuclear hepatocytes were the predominant histological features of SARS-CoV-2-infected liver.

The catalytic activity of noble-metal nanocrystals is mainly determined by their sizes and the facets exposed on the surface. For single crystals, it has been demonstrated that the Pd(100) surface is catalytically more active than both Pd(110) and Pd(111) surfaces for the CO oxidation reaction. Here we report the synthesis of Pd nanocrystals enclosed by {100} facets with controllable sizes in the range of 6-18 nm by manipulating the rate of reduction of the precursor. UV-vis spectroscopy studies indicate that the rate of reduction of Na 2 PdCl 4 can be controlled by adjusting the concentrations of Br -and Cl -ions added to the reaction mixture. Pd nanocrystals with different sizes were immobilized on ZnO nanowires and evaluated as catalysts for CO oxidation. We found that the activity of this catalytic system for CO oxidation showed a strong dependence on the nanocrystal size. When the size of the Pd nanocrystals was reduced from 18 nm to 6 nm, the maximum conversion rate was significantly enhanced by a factor of ~10 and the corresponding maximum conversion temperature was lowered by ~80 °C . KEYWORDS

Ni-rich transition metal layered oxide materials are of great interest as positive electrode materials for lithium ion batteries. As the popular electrode materials NMC (LiNi 1-x-y Mn x Co y O 2 ) and NCA (LiNi 1-x-y Co x Al y O 2 ) become more and more Ni-rich, they approach LiNiO 2 . Therefore it is important to benchmark the structure and electrochemistry of state of the art Li x NiO 2 for the convenience of researchers in the field. In this work, LiNiO 2 synthesized from a commercial Ni(OH) 2 precursor and modern synthesis methods shows a specific capacity close to the theoretical specific capacity of 274 mAh/g. In-situ X-ray diffraction (XRD) measurements were conducted to obtain accurate structural information versus lithium content, x. The known multiple phase transitions of Li x NiO 2 during charge and discharge were clearly observed, and the variation in unit cell lattice constants and volume was measured. Differential capacity versus voltage (dQ/dV vs. V) studies were used to investigate the electrochemical properties including regions of composition that show very slow kinetics. It is hoped that this work will be a useful reference for those working on Ni-rich positive electrode materials for Li-ion cells.