Oxygen activation on Ba-containing perovskite materials.

Oxygen activation, including oxygen reduction reaction (ORR) and oxygen evolution reaction (OER), is at the heart of many important energy conversion processes. However, the activation mechanism of Ba-containing perovskite materials is still ambiguous, because of the complex four-electron transfer process on the gas-solid interfaces. Here, we directly observe that BaO and BaO2 segregated on Ba-containing material surface participate in the oxygen activation process via the formation and decomposition of BaO2. Tens of times of increase in catalytic activities was achieved by introducing barium oxides in the traditional perovskite and inert Au electrodes, indicating that barium oxides are critical for oxygen activation. We find that BaO and BaO2 are more active than the B-site of perovskite for ORR and OER, respectively, and closely related to the high activity of Ba-containing perovskite.

In situ Dispersed Nano-Au on Zr-Suboxides as Active Cathode for Direct CO2 Electroreduction in Solid Oxide Electrolysis Cells.

CO2 electrochemical reduction in solid oxide electrolysis cells is an effective way to combine CO2 conversion and renewable electricity storage. A Au layer is often used as a current collector, whereas Au nanoparticles are rarely used as a cathode because it is difficult to keep nanosized Au at high temperatures. Here we dispersed a Au layer into Au nanoparticles (down to 2 nm) at 800 °C by applying high voltages. A 75-fold decrease in the polarization resistance was observed, accompanied by a 38-fold improvement in the cell current density. Combining electronic microscopy, in situ near-ambient pressure X-ray photoelectron spectroscopy, and theoretical calculations, we found that the interface between the Au layer and the electrolyte (yttria-stabilized zirconia (YSZ)) was reconstructed into nano-Au/Zr-suboxide interfaces, which are active sites that show a much lower reaction activation energy than that of the Au/YSZ interface. The formation of Zr-suboxides promotes Au dispersion and Au nanoparticle stabilization due to the strong interaction between Au and Zr-suboxides.

Preparation of aluminum sludge composite gel spheres and adsorption of U(IV) from aqueous solution.

A novel three-dimensional aluminum sludge/polyvinyl alcohol/sodium alginate(AS/PA/SA) gel spheres were designed and prepared for uranium(VI) adsorption, and it overcomes the shortcomings of poor recycling of powdery aluminum sludge adsorbent and poor stability of sodium alginate. Experiments show that the P-S-AS has a good pH range for removal of uranium (4-5). Fitting experimental data with pseudo-first-order kinetic model and pseudo-second-order kinetic model shows that the adsorption of U(VI) by P-S-AS is a chemical action. The fit of the Langmuir isotherm model and Freundlich isotherm model to the experimental data found that the P-S-AS adsorbed U(VI) to a single layer. Thermodynamic analysis shows that the adsorption occurs spontaneously, and an increase in temperature is favorable for the adsorption of uranium by the P-S-AS. Fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS) analysis of the P-S-AS before and after adsorption showed that the main adsorption mechanism was the complexation reaction between functional groups and U(VI), the bonding reaction between metal oxides and U(VI).

[Study on peparation of anemonin from Ranunculus japonicus Thunb].

OBJECTIVE: To study the preparation of anemonin from Ranunculus japonicus Thunb. METHODS: The best conditions of preparation for anemonin were optimized with monosyllabic experiments, such as using the purity of anemonin as a index for best selection of dying tempreture and the extraction ratio as another index for the concentration of NaCl and extracting times. The structures were clucidated on the basis of UV, IR, 1HNMR, 13CNMR, 1H-1H COSY, HMQC and HMQC spectra and chemical reactions and the purity is measured by HPLC. RESULTS: The best conditions for the extraction techniques of anemonin were 15% NaCl, four extracting times, 60 degrees C (0.08 Mpa) for drying. The purity of anemonin was 99% and yield rate was 0. 72 per thousand. Its quality was controlled. CONCLUSION: The preparation techniques are feasible and convenient.