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The efficiency of charge transfer at the interface of transition metals loaded on TiO2 as well as the active reduction site undoubtedly define the kinetics of H2 production. Here, we report the interfacial charge process of various transition metals (Fe, Ni, Cu, and Au) embedded in mesoporous core‐shell nanostructures, which provides further insight into the photocatalytic H2 evolution. Au was found to be the most active cocatalyst for the H2 evolution. Au nanoparticles (NPs) collect electrons and become a very efficient reduction site, promoting both charge separation and H2 evolution. The scavenging capacity of Au was found to be the highest compared to other NPs. Cu(I), which is as active as Au, but at a higher loading, also shows an ability for electron scavenging and acts as an active site under UV excitation, or rather injects electrons into the TiO2 conduction band under visible excitation. Ni(II) NPs were found to be involved in charge‐carrier separation through hole collection and their contribution to hydrogen evolution is expected to be limited to visible absorption and electron injection. The same behavior occurs with Fe(III), however, it is less efficient for H2 generation due to the weak charge‐carrier lifetime. We show that only Cu(I) could compete with noble metals such as Au, presenting electron‐scavenging behavior. Understanding the charge‐carrier dynamics will help design a very efficient system for photocatalytic H2 generation system. [ABSTRACT FROM AUTHOR]

In this study, the electronic and photocatalytic properties of core-shell heterojunctions photocatalysts with reversible configuration of TiO2 and Bi2O3 layers were studied. The core-shell nanostructure, obtained by efficient control of the sol-gel polymerization and impregnation method of variable precursors of semiconductors, makes it possible to study selectively the role of the interfacial charge transfer in each configuration. The morphological, optical, and chemical composition of the core-shell nanostructures were characterized by high-resolution transmission electron microscopy, UV-visible spectroscopy and X-ray photoelectron spectroscopy. The results show the formation of homogenous TiO2 anatase and Bi2O3 layers with a thickness of around 10 and 8 nm, respectively. The interfacial charge carrier dynamic was tracked using time resolved microwave conductivity and transition photocurrent density. The charge transfer, their density, and lifetime were found to rely on the layout layers in the core-shell nanostructure. In optimal core-shell design, Bi2O3 collects holes from TiO2, leaving electrons free to react and increase by 5 times the photocatalytic efficiency toward H2 generation. This study provides new insight into the importance of the design and elaboration of optimal heterojunction based on the photocatalyst system to improve the photocatalytic activity. [ABSTRACT FROM AUTHOR]

New biobased plasticizers made of di‐functional glycidyl ether epoxy cardanol (ECard) were investigated to improve the ductility of renewable poly(lactide) (PLA). Compatibility between PLA and ECard was achieved out through in situ reactive grafting strategy catalyzed with Ethyltriphenyl phosphonium bromide (ETPB) using twin‐screw extruder. In absence of catalyst, ECard forms domain ill‐dispersed in the PLA matrix due to the high incompatibility between both phases. When ETPB is added as catalyst domain size distribution of the plasticizer decreased, indicating an enhanced compatibility due to the reactive grafting of a fraction of ECard plasticizer onto PLA backbone. Although all plasticized PLA specimens exhibit lower glass transition temperature, lower elastic/tensile modulus, lower yield stress, and higher strain at break, the reactive blend containing the lowest amount of catalyst, that is, 0.02 phr, exhibited the highest ductility behavior. POLYM. ENG. SCI., 58:E64–E72, 2018. © 2017 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

A comparison of alumina (Al2O3) and boehmite (AlOOH) in (ammonium polyphosphate/melamine polyphosphate/metal oxide) ternary system was performed in poly(methyl methacrylate) on thermal and fire-resistance properties. A Design of Experiments (DoE) was then done for highlighting the best formulation out of both ternary systems. Laser flash analysis and scanning electron microscopy helped to explain some of the observations made by DoE. Mechanisms in both ternary systems during degradation also were investigated and modes of action could be presented based on pyrolysis-combustion flow calorimetry, Raman spectroscopy and X-ray diffraction. Copyright © 2011 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]