TY - JOUR A1 - Sachse, René A1 - Bernsmeier, D. A1 - Schmack, R. A1 - Häusler, I. A1 - Hertwig, Andreas A1 - Kraffert, K. A1 - Nissen, J. A1 - Kraehnert, R. T1 - Colloidal bimetallic platinum–ruthenium nanoparticles in ordered mesoporous carbon films as highly active electrocatalysts for the hydrogen evolution reaction JF - Catalysis Science & Technology N2 - Hydrogen features a very high specific energy density and is therefore a promising candidate for clean fuel from renewable resources. Water electrolysis can convert electrical energy into storable and transportable hydrogen gas. Under acidic conditions, platinum is the most active and stable monometallic catalyst for the hydrogen evolution reaction (HER). Yet, platinum is rare and needs to be used efficiently. Here, we report a synthesis concept for colloidal bimetallic platinum–ruthenium and rhodium–ruthenium nanoparticles (PtRuNP, RhRuNP) and their incorporation into ordered mesoporous carbon (OMC) films. The films exhibit high surface area, good electrical conductivity and well-dispersed nanoparticles inside the mesopores. The nanoparticles retain their size, crystallinity and composition during carbonization. In the hydrogen evolution reaction (HER), PtRuNP/OMC catalyst films show up to five times higher activity per Pt than Pt/C/Nafion® and PtRu/C/Nafion® reference catalysts. KW - Ordered mesoporous carbon KW - Bimetallic noble metal nanoparticles KW - Platinum-ruthenium colloid KW - Electrolysis KW - Hydrogen evolution reaction PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-506868 DO - https://doi.org/10.1039/C9CY02285F SN - 2044-4753 VL - 10 IS - 7 SP - 2057 EP - 2068 PB - Royal Society of Chemistry AN - OPUS4-50686 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kraffert, K. A1 - Kabelitz, Anke A1 - Siemensmeyer, K. A1 - Schmack, R. A1 - Bernsmeier, D. A1 - Emmerling, Franziska A1 - Kraehnert, R. T1 - Nanocasting of superparamagnetic iron oxide films with ordered mesoporosity JF - Advanced Materials Interfaces N2 - Maghemite and magnetite show superparamagnetic behavior when synthesized in a nanostructured form. The material’s inducible magnetization enables applications ranging from contrast enhancing agents for magnetic resonance imaging to drug delivery systems, magnetic hyperthermia, and separation. Superparamagnetic iron oxides with templated porosity have been synthesized so far only in the form of hard-templated powders, where silicon retained from the template severely degrades the material’s magnetic properties. Here, for the first time, the synthesis of superparamagnetic iron oxides with soft-templated mesopore structure is reported. The synthesis of nanostructured maghemite and magnetite films succeeds using micelles of amphiphilic block-copolymers as templates. A thermal treatment of the initially formed mesoporous ferrihydrite in nitrogen produces maghemite, which can be partly reduced to magnetite via thermal treatment in hydrogen while retaining the templated mesopore structure. The resulting materials feature a unique combination of high surface area, controlled pore diameter, and tunable magnetic properties. KW - Iron oxide films KW - Mesoporosity KW - Soft-templated PY - 2018 DO - https://doi.org/10.1002/admi.201700960 SN - 2196-7350 VL - 5 IS - 3 SP - 1700960, 1 EP - 1700960, 7 PB - Wiley-VCH CY - Weinheim AN - OPUS4-43560 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Frisch, M. A1 - Laun, J. A1 - Marquardt, Julien A1 - Arinchtein, A. A1 - Bauerfeind, K. A1 - Bernsmeier, D. A1 - Bernicke, M. A1 - Bredow, T. A1 - Kraehnert, R. T1 - Bridging experiment and theory: enhancing the electrical conductivities of soft-templated niobium-doped mesoporous titania films† JF - Physical Chemistry Chemical Physics N2 - Theoretical calculations suggest a strong dependence of electrical conductivity and doping concentration in transition-metal doped titania. Herein, we present a combined theoretical and experimental approach for the prediction of relative phase stability and electrical conductivity in niobium-doped titania as model system. Our method paves the way towards the development of materials with improved electrical properties. KW - Electrical conductivity KW - Prediction relative KW - Transition-metal doped KW - System method PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-521371 DO - https://doi.org/10.1039/d0cp06544g SN - 1463-9084 VL - 23 IS - 5 SP - 3219 EP - 3224 PB - Royal Society of Chemistry AN - OPUS4-52137 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -