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We report the synthesis of core‐shell Ni−Pt nanoparticles (NPs) with varying degrees of crystallographic facets and surface layers rich in Pt via a seed‐mediated thermolytic approach. Mixtures of different surfactants used during synthesis resulted in preferential surface passivation, which in turn dictated the size, chemical composition, and geometric evolution of these PtNi NPs. Electrochemical investigations of these pristine core‐shell Ni−Pt structures in the oxygen reduction reaction (ORR) show that their catalytic functionalities outperform the commercial Pt/C reference catalyst. The enhanced electrocatalytic ORR performances of these Pt‐based PtNi NPs are correlated with the weakened oxygen binding strength or surface‐adsorbed hydroxyl (OH) species on active Pt surface sites induced by the downshift of the d‐band center as a result of compressive strain effects. Our studies offer a robust synthetic approach for the development of core‐shell nanostructures for enhanced ORR catalysis. [ABSTRACT FROM AUTHOR]

The direct formation of formaldehyde in the selective, aerobic oxidation of methane in the presence of liquid water at ca. 498 K has recently been described. One of the intriguing observations in the aerobic oxidation of methane over platinum in the presence of water is the absence of the typically observed negative selectivity‐conversion dependency (up to a methane conversion of 1 %). In this perspective, the main differences between this route and other methods for the selective oxidation of methane are being described. Possible reaction pathways for the formation of formaldehyde are discussed. Further developments for this newly developed methane activation route are highlighted. [ABSTRACT FROM AUTHOR]

Benzyl alcohol can be oxidized selectively to benzaldehyde over platinum-based catalysts using either oxygen (O2, supplied in the form of synthetic air) or the more powerful hydrogen peroxide (H2O2) as the oxidant. Here we compare these oxidants in the aqueous phase oxidation of benzyl alcohol in a batch reactor at 363.15 K or 393.15 K over monodisperse Pt and Pt–Ni nanostructures synthesized with molybdenum hexacarbonyl (Mo(CO)6) as a reductant. The initial catalytic activity of either Pt or a Pt–Ni alloy anchored on titania support (TiO2) is much higher when using H2O2 than when using O2 (supplied in the form of synthetic air). However, the high initial activity using H2O2 is accompanied by a strong decrease in the activity over Pt. Alloying Pt with Ni results in a reduction in the activity in the benzyl alcohol oxidation when using O2 but enhances the initial activity when using H2O2. The results are rationalized based on a change in the relative surface concentration of oxygen-containing species upon changing the oxidant or alloying Pt with Ni. [ABSTRACT FROM AUTHOR]

The current study focuses on the photocatalytic oxidation of benzyl alcohol in acetonitrile under air bubbling conditions comparing titania-based materials, Cu–MOF, and Cu–MOF–NH2 as semiconductor photocatalysts. The catalysts were characterized by XRD, N2 adsorption–desorption isotherm, FTIR, Raman spectroscopy, and TEM. The photocatalytic benzyl alcohol conversion reached ~100% after exposing the four prepared catalysts to a 125 W mercury lamp for up to 240 min. Benzaldehyde is formed with a moderate selectivity (after a reaction time of 60 min. ca. 30, 37 and 45% over the titania-based catalysts, Cu–MOF, and Cu–MOF–NH2, respectively). The formation of electron-hole pairs at the surface of the semiconductor nanoparticles followed by oxidation reaction was the suggested mechanism. The initial rate of benzyl alcohol oxidation was 4.6 and 4.7 mmol g–1 min–1 for titania-based materials. Cu–MOF and Cu–MOF–NH2 showed a higher initial rate of reaction of 6.1 and 9.1 mmol g–1 min–1. According to preliminary research, decorating MOF linker by amine (MOF–NH2) could improve visible-light harvesting, charge separation, and electron transport of the catalyst, resulting in increased photocatalytic activity. The current work offers some directions for the development of MOF-based photocatalysts for organic synthesis. [ABSTRACT FROM AUTHOR]