Doctoral College TU-D Unravelling advanced 2D materials
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Synthesis and Interfaces of 1D/2D hybrids

Dominik Eder, Institute of Materials Chemistry

Research in the DE group focuses on the rational synthesis and structural/functional characterization of novel energy materials (e.g. photocatalysts and electrode materials) as well as on micro- and mesoporous materials (zeolites, bioactive glasses). We are particularly interested in engineering interfaces through combination of 1D/2D nanomaterials into composites and hybrids (e.g. inorganic-inorganic, nanocarbon-inorganic, nanocarbon-polymer) [1,4-5] and in introducing large ordered mesopores to enhance interior active surface areas through soft and hard templating (e.g. tailor-made co-blockpolymers) [3]. These materials are characterized in detail with WAXS/SAXS, SEM/TEM, XPS/UPS, IR/RAMAN/DRS, BET/BJH and thermal analysis. In particular, we aim to unravel the nature of catalytically active sites an understand the adsorption kinetics and charge/energy transfer dynamics at solid-solid, solid-liquid and solid-gas interfaces using state-of-the-art spectroscopic techniques, such as transient photoluminescence, photochronoamperometry and (photo)impedance spectroscopy (CIMPS/EIS).  We further investigate the growth dynamics of inorganic nanomaterials on nanocarbon surfaces [1-2] and modify electronic interfaces in hybrids through defect engineering an heteroatom doping. These fundamental studies are complemented by applied projects that aim to evaluate and improve the performance of these materials in socioeconomically important areas such as energy (e.g. light-to-fuel conversion [1]), environment (e.g. water purification) and medicine (e.g. tissue engineering).

PhD Project 1: Nanocarbon-inorganic hybrids as new-generation electrochemical sensors

Co-supervisor: Hannes Mikula


The first PhD project is devoted to designing new nanocarbon-inorganic hybrid structures for electrochemical biosensing, i.e. highly sensitive and site-selective detection of antibodies and proteins. These comprise of multiple 1D/2D building blocks involving doped nanocarbons (e.g. CNTs, graphene, unique CNT fibres) and functional inorganics (e.g. transition metal oxides, zeolites). We employ atomic layer deposition (ALD) to deposit ultrathin, conformal coatings on porous 1D/2D nanocarbon assemblies at low reaction temperatures with precise thickness control at the atomic scale. The materials’ morphology, composition and electronic structure are characterized using various state-of-the-art techniques (e.g. HRTEM/SEM, XRD, Raman/FTIR, BET/BJH, UPS/XPS, MS-EIS). Particular focus is directed towards engineering the hybrids’ interfaces and surfaces through chemical means (e.g. covalent/non-covalent/electrostatic) and through materials science (e.g. epitaxial growth, defect engineering), with the aim to enhance the electronic and structural coupling between the hybrid’s components as well as to allow for tuning sensitivity and selectivity in electrochemical sensors and catalytic applications. This project is designed to benefit from close collaborations with other DK members, including HM (e.g. functionalizations and sensing applications), PB (e.g. electronic and defect structure and transport properties) and GP (surface properties and catalytic processes).

PhD Project 2: Dynamics of interfacial processes in 2D layered sandwich structures

Co-supervisor: Thomas Müller

The second project is dedicated to inorganic (IO) 2D-layered materials and IO/IO and C/IO layered sandwich structures, involving mixed bismuth oxyhalides (BiOX, X=Cl, Br, J), doped MoO x , metal chalcogenides, as well as graphene and carbon nitride. We will synthesize these materials from molecular precursors (“bottom-up”) or via exfoliation processes from bulk materials (“top-down”) and characterize them by a range of spectroscopic (Raman/FTIR, XPS/UPS, ellipsometry, PL) and microscopic (HRTEM, AFM) techniques at the nanoscale. The focus lies in modifying and evaluating their electronic structures and interfaces by “down-scaling” (i.e. quantum size effects), heteroatom doping (i.e. defect engineering) and hybridization (i.e. Fermi-level engineering) using both experimental and theoretical techniques (in collaboration with DK members TM and FL, respectively). In particular, we will investigate the effects of the electronic structure on light absorption and charge extraction properties and provide mechanistic insights into photocatalytic pathways. This will also allow evaluating their performance in photocatalysis (e.g. Z-scheme artificial photosynthesis, solar- to-fuel conversion, CO 2 reduction), nanoelectronics and optoelectronics.


Literature

  1. A. Cherevan, et al.: Interface engineering in nanocarbon-Ta2O5 hybrid photocatalysts.  Energy Environ. Sci. 7, 791-796 (2014) DOI: 10.1039/C3EE42558D
  2. Z. Ren, et al.: Hybridizing photoactive zeolites with graphene: a powerful strategy. Chem. Sci. 3, 209-216 (2012). DOI: 10.1039/C1SC00511A
  3. S. Guldin, et al., Improved conductivity in dye-sensitized solar cells through block-copolymer confined TiO2 crystallization. Energy Environ. Sci. 4, 225-233 (2011) DOI: 10.1039/c0ee00362je
  4. D. Eder*: Carbon nanotube-inorganic hybrid materials. Chem. Rev. 110, 1348–1385 (2010) DOI: 10.1021/cr800433k
  5. D. Eder* and A. H. Windle: Carbon-inorganic hybrid materials: the carbon nanotube-TiO2 interface. Adv. Mater. 20, 1787-1793 (2008) DOI: 10.1002/adma.200702835