Surface Modification of ZrO2–3Y2O3 with Highintensity Pulsed N2+ Ion Beams

Russian Physics Journal -     

A periodic DFT study on adsorption of small molecules(CH4,CO,H2O,H2S,NH3)on the WO3(001) surface-supported Au

Gas molecules(such as CH4,CO,H2O,H2S,NH_3)adsorption on the pure and Au-doped WO3(001)surface have been studied by Density functional theory calculations with generalized gradient approximation.Based on the the calculation of adsorption energy,we found the most stable adsorption site for gas molecules by comparing the adsorption energies of different gas molecules on the WO3(001)surface.We have also compared the adsorption energy of five different gas molecules on the WO3(001)surface,our calculation results show that when the five kinds of gases are adsorbed on the pure WO3(001)surface,the order of the surface adsorption energy is CO>H2S>CH4>H2O>NH3.And the results show that NH3 is the most easily adsorbed gas among the other four gases adsorbed on the surface of pure WO3(001)surface.We also calculated the five different gases on the Au-doped WO3(001)surface.The order of adsorption energy was found to be different from the previous calculation:CO>CH4>H2S>H2O>NH3.These results provide a new route for the potential applications of Au-doped WO3 in gas molecules adsorption.     

Synthesis and stability evaluation of hierarchical silicoaluminophosphates with different structural frameworks in the methanol to olefins process

Silicoaluminophosphates (SAPOs) with different pore structures were synthesized through the implementation of polyethylene glycol (PEG) as a mesopores impregnation agent. Using PEGs with different molecular weights (MWs) and concentrations in the synthesis precursor, several samples were synthesized and characterized. Applying a PEG capping agent to the precursors led to the formation of tuned mesopores within the microporous matrix of the SAPO. The effects of the PEG molecular weight and PEG/Al molar ratio were investigated to maximize the efficiency of the catalyst in the methanol-to-olefin (MTO) process. Using PEG with a MW of 6000 resulted in the formation of both Zeolite Rho and chabazite structural frameworks (i.e., DNL-6 and SAPO-34). Pure SAPO-34 samples were successfully prepared using PEG with a MW of 4000. Our results showed that the PEG concentrations affect the porosity and acidity of the synthesized materials. Furthermore, the SAPO-34 sample synthesized with PEG (MW of 4000) and a PEG/Al molar ratio of 0.0125 showed a superior catalytic stability in the MTO reaction owing to the tuned bi-modal porosity and tailored acidity pattern. Finally, through reactivation experiments, it was found that the catalyst is stable even after several regeneration cycles.     

Cooperative coupling of photocatalytic production of H2O2 and oxidation of organic pollutants over gadolinium ion doped WO3 nanocomposite

This work reported the lanthanide ion (Gd³⁺) doped tungsten trioxide (Gd-WO₃) nanocrystal for remarkable promoted photocatalytic degradation of organic pollutants and simultaneous in-situ H₂O₂ production. With doped lanthanide ion (Gd³⁺), Gd-WO₃ showed a much broad and enhanced solar light absorption, which not only promoted the photocatalytic degradation efficiency of organic compounds, but also provided a suitable bandgap for direct reduction of oxygen to H₂O₂. Additionally, the isolated Gd³⁺ on WO₃ surface can efficiently weaken the *OOH binding energy, increasing the activity and selectivity of direct reduction of oxygen to H₂O₂, with a rate of 0.58 mmol L⁻¹ g⁻¹ h⁻¹. The in-situ generated H₂O₂ can be subsequently converted to ^•OH based on Fenton reaction, further contributed to the overall removal of organic pollutants. Our results demonstrate a cascade photocatalytic oxidation-Fenton reaction which can efficiently utilize photo-generated electrons and holes for organic pollutants treatment.     

Carbon dots and polyurethane composite for photo-induced elimination of uranium under air atmosphere

Uranium is the main fuel of nuclear power and elimination uranium from nuclear wastewater is significant both in environmental protection and fuel recycle. Here we report for the first time the synthesis of carbon dots/polyurethane(CDs/PU) composite materials for the photoinduced elimination of uranium from water. Irradiated with visible light, CDs/PU could eliminate uranium efficiently with the generation of(UO₂)O₂·2H₂O as solid products in air. The further inve...     

Grain Boundary Electronic Insulation for High-Performance All-Solid-State Lithium Batteries

Sulfide electrolytes with high ionic conductivities are one of the most highly sought for all-solid-state lithium batteries (ASSLBs). However, the non-negligible electronic conductivities of sulfide electrolytes (≈10⁻⁸ S cm⁻¹) lead to electron smooth transport through the sulfide electrolyte pellets, resulting in Li dendrite directly depositing at the grain boundaries (GBs) and serious self-discharge. Here, a grain-boundary electronic insulation (GBEI) strategy is proposed to block electron transport across the GBs, enabling Li−Li symmetric cells with 30 times longer cycling life and Li−LiCoO₂ full cells with three times lower self-discharging rate than pristine sulfide electrolytes. The Li−LiCoO₂ ASSLBs deliver high capacity retention of 80 % at 650 cycles and stable cycling performance for over 2600 cycles at 0.5 mA cm⁻². The innovation of the GBEI strategy provides a new direction to pursue high-performance ASSLBs via tailoring the electronic conductivity.     

Elution–extrusion counter-current chromatographic separation and theoretical mechanism of antioxidant from Robinia pseudoacacia flower

Robinia pseudoacacia flowers have attracted much attention because of numerous bioactivities. In this study, its extract showed the potential scavenging ability for 2,2′-azinobis-(3-ethylbenzthiazoline-6-sulphonate) and 1,1-diphenyl-2-picrylhydrazyl free radicals. Under the guidance of antioxidant activity, the antioxidant extract was enriched by liquid-liquid extraction. The partition coefficients of the two main components in antioxidant extracts differed greatly, so in this study, elution-extrusion counter-current chromatography with the solvent system of n-hexane-ethyl acetate-methanol-water (2.5:5:2.5:5, v/v) was used to enhance the separation efficiency, and the two main components were successfully obtained. Among them, kaempferol showed strong antioxidant activity, which can be responsible for the activity of the extract. In order to deeply understand the antioxidant mechanism of kaempferol, the thermodynamics, frontier molecular orbital, and kinetics of scavenging free radicals were investigated by density functional theory. The results showed that 4′-OH in kaempferol was the most active group, which can scavenge free radicals by hydrogen atom transfer in non-polar solvents and activate 3-OH to generate double hydrogen atom transfer in the gas phase. But in polar solvents, it was more inclined to clear radicals through single electron transfer and proton transfer. The kinetic result showed that kaempferol needed 9.17 kcal/mol of activation energy to scavenge free radicals.     

Influence of polymer reprocessing cycles on the microstructure and rheological behavior of polypropylene/mineral oil oleogels

The overall objective of this work was to study the effect of reprocessing cycles of isotactic polypropylene (PP) on the rheological behavior and microstructure of gel-like dispersions in mineral oil. PP was subjected to 10 reprocessing cycles and oleogel samples were further prepared by using the mixing rheometry technique and characterized from a rheological point of view and polarized light optical microscopy (PLOM). Recycled polymer samples were also characterized by means of rheological measurements, differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) to evaluate the property changes induced by reprocessing. The values of different linear viscoelastic functions (elastic modulus and complex viscosity) of recycled PP decrease with the number of reprocessing cycles, which influences oleogel rheological response. An empirical exponential correlation between the storage modulus (G′) of PP samples and the plateau modulus ($G_N^o$) of oleogels has been proposed to predict the rheological behavior of oleogels. Results were explained considering the scission of PP chains induced by the thermomechanical reprocessing treatment applied.     

A Method for Microalgae Proteomics Analysis Based on Modified Filter-Aided Sample Preparation

With the fast development of microalgal biofuel researches, the proteomics studies of microalgae increased quickly. A filter-aided sample preparation (FASP) method is widely used proteomics sample preparation method since 2009. Here, a method of microalgae proteomics analysis based on modified filter-aided sample preparation (mFASP) was described to meet the characteristics of microalgae cells and eliminate the error caused by over-alkylation. Using Chlamydomonas reinhardtii as the model, the prepared sample was tested by standard LC-MS/MS and compared with the previous reports. The results showed mFASP is suitable for most of occasions of microalgae proteomics studies.