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In this work, Ru–CeO2 prepared by a "melting" method and used as a heterogeneous catalyst for ethylene methoxy-carbonylation was investigated, together with two other catalysts prepared by impregnation and aerosol methods. The Ru–CeO2 (1%-M) catalyst demonstrates activity significantly higher than that of the other catalysts with the same Ru content. The XPS and Raman analysis results suggest that the Ru–CeO2 (1%-M) oxygen vacancy content is not the highest among the catalysts prepared using the three methods, even though the content oxygen vacancies have been reported to play a crucial role in carbonylation when using a Ru–CeO2 catalyst. It was discovered that the available Ru0 (Ru0 in the freshly prepared sample plus that being transformed from Run+ during reduction) is the other decisive factor in determining the catalyst's performance. We further investigated the high reducibility of the catalyst prepared by using the melting method and discovered that a weak metal–support interaction could be obtained because of the independent formations of Ru and CeO2 crystals with graphite carbon as the barrier. Removing carbon under the optimal conditions could facilitate the as-formed Ru crystals anchored onto CeO2; therefore, there is no strong interaction between Ru and CeO2. [ABSTRACT FROM AUTHOR]

Emerging nanomaterials are being manufactured with varying particle sizes, morphologies, and crystal structures in the pursuit of achieving outstanding functional properties. These variations in these key material properties of nanoparticles may affect their environmental fate and transport. To date, few studies have investigated this important aspect of nanoparticles' environmental behavior. In this study, the aggregation kinetics of ten different TiO2 nanoparticles (5 anatase and 5 rutile each with varying size) was systematically evaluated. Our results show that, as particle size increases, the surface charge of both anatase and rutile TiO2 nanoparticles shifts toward a more negative value, and, accordingly, the point of zero charge shifts toward a lower value. The colloidal stability of anatase sphere samples agreed well with DLVO theoretical predictions, where an increase in particle size led to a higher energy barrier and therefore greater critical coagulation concentration. In contrast, the critical coagulation concentration of rutile rod samples correlated positively with the specific surface area, i.e., samples with higher specific surface area exhibited higher stability. Finally, due to the large innate negative surface charge of all the TiO2 samples at the pH value (pH = 8) tested, the addition of natural organic matter was observed to have minimal effect on TiO2 aggregation kinetics, except for the smallest rutile rods that showed decreased stability in the presence of natural organic matter.

Encapsulation of drugs within nanocarriers that selectively target malignant cells promises to mitigate side effects of conventional chemotherapy and to enable delivery of the unique drug combinations needed for personalized medicine. To realize this potential, however, targeted nanocarriers must simultaneously overcome multiple challenges, including specificity, stability and a high capacity for disparate cargos. Here we report porous nanoparticle-supported lipid bilayers (protocells) that synergistically combine properties of liposomes and nanoporous particles. Protocells modified with a targeting peptide that binds to human hepatocellular carcinoma exhibit a 10,000-fold greater affinity for human hepatocellular carcinoma than for hepatocytes, endothelial cells or immune cells. Furthermore, protocells can be loaded with combinations of therapeutic (drugs, small interfering RNA and toxins) and diagnostic (quantum dots) agents and modified to promote endosomal escape and nuclear accumulation of selected cargos. The enormous capacity of the high-surface-area nanoporous core combined with the enhanced targeting efficacy enabled by the fluid supported lipid bilayer enable a single protocell loaded with a drug cocktail to kill a drug-resistant human hepatocellular carcinoma cell, representing a 10(6)-fold improvement over comparable liposomes.

Here we report a new high‐Q × f and temperature‐stable oxyfluoride microwave dielectric ceramic system of Li2+xZrO3Fx (0 ≤ x ≤ 1.25) sintered at low temperatures (i.e., ≤950°C). The sintering characteristics, phase assemblage, microstructures, and microwave dielectric properties (MDPs) of the Li2+xZrO3Fx specimens were studied. The chemical bond theory calculations were employed to analyze the compositional dependence of the MDPs in the Li2+xZrO3Fx ceramic system. The optimal MDPs of εr = 15.8, Q × f = 65 100 GHz, and τf = 1.2 ppm/°C were achieved in the sample with x = 1. Besides, the ceramic samples exhibited high chemical compatibility with Ag electrodes. Therefore, the novel ceramic system of Li2+xZrO3Fx is confirmed to be a promising candidate as a low‐temperature co‐fired ceramic material. [ABSTRACT FROM AUTHOR]

Cu–CeO2/C composite catalysts with porous structure were prepared by a microwave-assisted carbonization–impregnation method, which demonstrated a significant performance enhancement for the selective hydrogenation of ethylene carbonate. It was shown by XRD, BET, SEM, TEM, XPS and H2-TPR that Cu–CeO2/C catalysts with appropriate copper-ceria interactions improving the dispersion of copper particles and providing a higher ratio of Cu+/(Cu+ + Cu0) and more oxygen vacancies on the surface. These interactions resulted in an enhanced adsorption of ethylene carbonate and a high hydrogenation activity. The effect of significant operating conditions such as reaction temperature, H2 pressure and substrate ratio on the EC hydrogenation activity over the Cu–CeO2/C catalyst was also investigated to predict the optimal conditions to achieve maximum activity in this process. [ABSTRACT FROM AUTHOR]