Article pubs.acs.org/cm
Pd@Fe2O3 Superparticles with Enhanced Peroxidase Activity by Solution Phase Epitaxial Growth Martin Kluenker,† Muhammad Nawaz Tahir,*,† Ruben Ragg,† Karsten Korschelt,† Paul Simon,‡ Tatiana E. Gorelik,§ Bastian Barton,§ Sergii I. Shylin,† Martin Panthöfer,† Jana Herzberger,∥,⊥ Holger Frey,∥ Vadim Ksenofontov,† Angela Möller,† Ute Kolb,§ Juri Grin,‡ and Wolfgang Tremel*,† †
Institut für Anorganische Chemie und Analytische Chemie, Johannes Gutenberg-Universität, Duesbergweg 10-14, 55128 Mainz, Germany ‡ Max-Planck-Institut für Chemische Physik fester Stoffe, Nöthnitzer Straße 40, 01187 Dresden, Germany § Institut für Physikalische Chemie, Johannes Gutenberg-Universität, Duesbergweg 10-14, 55128 Mainz, Germany ∥ Institut für Organische Chemie, Johannes Gutenberg-Universität, Duesbergweg 10-14, 55128 Mainz, Germany ⊥ Graduate School Materials Science in Mainz, Staudinger Weg 9, 55128 Mainz, Germany S Supporting Information *
ABSTRACT: Compared to conventional deposition techniques for the epitaxial growth of metal oxide structures on a bulk metal substrate, wet-chemical synthesis based on a dispersible template offers advantages such as low cost, high throughput, and the capability to prepare metal/metal oxide nanostructures with controllable size and morphology. However, the synthesis of such organized multicomponent architectures is difficult because the size and morphology of the components are dictated by the interplay of interfacial strain and facet-specific reactivity. Here we show that solution-processable two-dimensional Pd nanotetrahedra and nanoplates can be used to direct the epitaxial growth of γ-Fe2O3 nanorods. The interfacial strain at the Pd−γFe2O3 interface is minimized by the formation of an FexPd “buffer phase” facilitating the growth of the nanorods. The γ-Fe2O3 nanorods show a (111) orientation on the Pd(111) surface. Importantly, the Pd@γ-Fe2O3 hybrid nanomaterials exhibit enhanced peroxidase activity compared to that of isolated Fe2O3 nanorods with comparable surface area because of a synergistic effect for the charge separation and electron transport. The metal-templated epitaxial growth of nanostructures via wet-chemical reactions appears to be a promising strategy for the facile and high-yield synthesis of novel functional materials.
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INTRODUCTION Epitaxial growth is a promising strategy for the controlled growth of one-dimensional nanostructures with a preferred orientation and alignment on substrate layers, which may lead to advances in areas such as energy harvesting or conversion, sensing, catalysis, optical, electrical, optoelectronic, and magnetic applications.1−8 Vapor deposition (PVD, CVD, and ALD) approaches, often relying on the vapor−liquid−solid (VLS) technique, electrochemical deposition, or laser ablation, have been widely used to induce the epitaxial growth of metal oxide semiconductors.9−12 Major disadvantages of these deposition techniques requiring ultra-high-vacuum conditions or special equipment are low throughput and high cost. © 2016 American Chemical Society
Therefore, wet-chemical approaches are an attractive alternative because of their versatility, easy implementation, and low cost. The epitaxial growth of metal oxides has been demonstrated previously in the synthesis of ferroelectric perovskite films [e.g., lead zirconate titanate, Pb(Zr,Ti)O3 (PZT)] on oxide substrates, which can be achieved because of a tolerable lattice mismatch (
