TY - JOUR A1 - Schmack, R. A1 - Eckhardt, B. A1 - Koch, G. A1 - Ortel, Erik A1 - Kraehnert, R. T1 - ZnO coatings with controlled pore size, crystallinity and electrical conductivity N2 - Zinc oxide is a wide bandgap semiconductor with unique optical, electrical and catalytic properties. Many of its practical applications rely on the materials pore structure, crystallinity and electrical conductivity. We report a synthesis method for ZnO films with ordered mesopore structure and tuneable crystallinity and electrical conductivity. The synthesis relies on dip-coating of solutions containing micelles of an amphiphilic block copolymer and complexes of Zn2+ ions with aliphatic ligands. A subsequent calcination at 400 °C removes the template and induces crystallization of the pore walls. The pore structure is controlled by the template polymer, whereas the aliphatic ligands control the crystallinity of the pore walls. Complexes with a higher thermal stability result in ZnO films with a higher content of residual carbon, smaller ZnO crystals and therefore lower electrical conductivity. The paper discusses the ability of different types of ligands to assist in the synthesis of mesoporous ZnO and relates the structure and thermal stability of the precursor complexes to the crystallinity and electrical conductivity of the zinc oxide. KW - conductivity KW - EISA KW - pore templating KW - pore size control KW - ligands KW - zinc oxide PY - 2016 U6 - https://doi.org/10.5755/j01.ms.22.1.8634 SN - 1392–1320 VL - 22 IS - 1 SP - 74 EP - 81 PB - Kaunas University of Technology, Lithuania AN - OPUS4-35550 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bernsmeier, D. A1 - Bernicke, M. A1 - Ortel, Erik A1 - Bergmann, A. A1 - Lippitz, Andreas A1 - Nissen, J. A1 - Schmack, R. A1 - Strasser, P. A1 - Polte, J. A1 - Kraehnert, R. T1 - Nafion-free carbon-supported electrocatalysts with superior hydrogen evolution reaction performance by soft templating N2 - Efficient water electrolysis requires electrode coatings with high catalytic activity. Platinum efficiently catalyzes the hydrogen evolution reaction in acidic environments, but is a rare and expensive metal. The activity achieved per metal atom can be increased if small Pt particles are dispersed onto electrically conductive, highly accessible and stable support materials. However, the addition of Nafion, a typical binder material used in the manufacture of electrode coatings, can decrease catalytic activity by the blocking of pores and active surface sites. A new approach is reported for the direct synthesis of highly active Nafion-free Pt/C catalyst films consisting of small Pt nanoparticles supported in size-controlled mesopores of a conductive carbon film. The synthesis relies on the co-deposition of suitable Pt and C precursors in the presence of polymer micelles, which act as pore templates. Subsequent carbonization in an inert atmosphere produces porous catalyst films with controlled film thickness, pore size and particle size. The catalysts clearly outperform all Nafion-based Pt/C catalysts reported in the literature, particularly at high current densities. KW - XPS KW - SEM KW - TEM KW - SAXS KW - Catalysis KW - Electrochemistry PY - 2017 U6 - https://doi.org/10.1002/celc.201600444 SN - 2196-0216 VL - 4 IS - 1 SP - 221 EP - 229 PB - Wiley Online Library CY - Weinheim AN - OPUS4-39733 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -