The development of nonprecious catalysts for water splitting into hydrogen and oxygen is one of the major challenges to meet future sustainable fuel demand. Herein, thin layers of manganese oxide nanosheets supported on nitrogen-functionalized carbon nanotubes (NCNTs) were formed by the treatment of NCNTs dispersed in aqueous solutions of KMnO or CsMnO under reflux or under hydrothermal (HT) conditions and used as electrocatalysts for the oxygen evolution reaction (OER) in alkaline media. The samples were characterized by X-ray photoelectron spectroscopy, X-ray diffraction, transmission electron microscopy, and Raman spectroscopy.
View Article and Find Full Text PDFWe herein present a series of hitherto unprecedented seleno-pentlandites (Fe4.5Ni4.5S8-YSeY).
View Article and Find Full Text PDFA facile strategy is reported for the synthesis of Fe/Co mixed metal oxide nanoparticles supported on, and embedded inside, high purity oxidized multiwalled carbon nanotubes (MWCNTs) of narrow diameter distribution as effective bifunctional catalysts able to reversibly drive the oxygen evolution reaction (OER) and the oxygen reduction reaction (ORR) in alkaline solutions. Variation of the Fe/Co ratio resulted in a pronounced trend in the bifunctional ORR/OER activity. Controlled synthesis and in-depth characterization enabled the identification of an optimal Fe/Co composition, which afforded a low OER/OER reversible overvoltage of only 0.
View Article and Find Full Text PDFManganese oxides are promising electrocatalysts for the oxygen evolution reaction due to their versatile redox properties. Manganese oxide (MnO) nanoparticles were synthesized on oxygen- and nitrogen-functionalized carbon nanotubes (OCNTs and NCNTs) by calcination in air of Mn-impregnated CNTs with a loading of 10 wt% Mn. The calcined samples were exposed to reducing conditions by thermal treatment in H or NH, and to strongly oxidizing conditions using HNO vapor, which enabled us to flexibly tune the oxidation state of Mn from 2+ in MnO to 4+ in MnO.
View Article and Find Full Text PDFDeveloping high-performance non-precious metal catalysts (NPMCs) for the oxygen-reduction reaction (ORR) is of critical importance for sustainable energy conversion. We report a novel NPMC consisting of iron carbide (Fe C) nanoparticles encapsulated in N-doped bamboo-like carbon nanotubes (b-NCNTs), synthesized by a new metal-organic framework (MOF)-templated assembly approach. The electrocatalyst exhibits excellent ORR activity in 0.
View Article and Find Full Text PDFThe high (de)lithiation potential of TiO (ca. 1.7 V vs Li/Li in 1 M Li) decreases the voltage and, thus, the energy density of a corresponding Li-ion battery.
View Article and Find Full Text PDFCo-based layered double hydroxide (LDH) catalysts with Fe and Al contents in the range of 15 to 45 at % were synthesized by an efficient coprecipitation method. In these catalysts, Fe or Al ions play an essential role as trivalent species to stabilize the LDH structure. The obtained catalysts were characterized by a comprehensive combination of surface- and bulk-sensitive techniques and were evaluated for the oxygen evolution reaction (OER) on rotating disk electrodes.
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