Photocatalytic reduction of CO2 into solar fuels is an exciting prospect towards solving grand environmental and energy challenges. Key to this process is the use of a photocatalyst with efficient light absorption, charge transport and catalytic conversion, using scalable and cheap materials. 2D metal chalcogenides as well as layered metal-organic frameworks (MOFs) and metal chalcogenolates (MOCHAs) constitute invaluable catalysts in closely related electro/photocatalytic hydrogen evolution reaction [1, 2]. In contrast, little work has explored these hybrids for electro/photocatalytic CO2 reduction [3, 4]. It remains unknown how they act as light absorbers and/or co-catalyst, where reactant species adsorb and how effective charge transfer proceeds and what the underlying catalytic CO2 reduction mechanisms are.

Left: 2D-Metal chalcogenolate assemblies. Right: Transient IR-ATR studies A) following the photodeposition of Pt and B) photocatalytic steam reforming of methanol over Platinum on Titania [5].

© Dominik Eder

Left: 2D-Metal chalcogenolate assemblies. Right: Transient IR-ATR studies A) following the photodeposition of Pt and B) photocatalytic steam reforming of methanol over Pt/TiO2 [5].

Goals

We aim to design 2D layered metal chalcogenides/chalcogenolate as well as MOFs and combine them with molecular species of earth-abundant metals/metal oxides (M/MO) to explore their prospects and reaction mechanisms toward photocatalytic CO2 reduction. We will a) develop synthetic strategies for the controlled attachment of ultrafine M/MO clusters (e.g. Cu, Ni, Ti) by introducing defects and dopants as anchoring sites, b) investigate the dynamics of interfacial charge/energy transfer, c) identify the chemical, electronic and structural state of the active sites, and d) unravel the adsorption and conversion of reaction intermediates using a unique live-monitoring photoreactor setup combined with in-situ FTIR-DRIFTS/ATR spectroscopy.

Methods

M/MO single-atoms and clusters will be deposited on pre-engineered 2D MoS 2 films via ALD or in suspension during liquid-phase exfoliation (“in situ approach”). The materials will be characterized with respect to a) location and dispersion of the M/MO clusters with high resolution (S)TEM and chemisorption, b) chemical state and band levels of MoS 2 and M/MO with XPS and UV-vis/DRS, c) chemical, thermal and structural stability with IR/Raman, ICP-MS, (S)TEM and TGA, and d) interfacial charge transfer dynamics by time-resolved photoluminescence (PL). Photocatalysis experiments will be conducted in our cutting-edge photoreactor that combines fast, online reactant monitoring with in-situ surveillance by transient FTIR-DRIFT/ATR spectroscopy to elucidate mechanistic details regarding adsorbates and intermediate species.

Collaborations

2D metal chalcogenide films are provided by Mueller (CVD) and complimented by our own liquid-phase exfoliated materials. Holzer will provide organic components for the synthesis of MOFs and MOCHAs. The introduction of defects occurs in collaboration with Wilhelm (ion bombardment). Foelske will provide XPS, Lendl spatially resolved AFM- Raman/IR, Kotakoski high-resolution STEM, and Parkinson atomically resolved STM/TPD/IR studies. Computational support on the structural environment of our hybrids and their electronic properties via simulated XPS, PL and IR spectra will be provided by Libisch and Madsen. Marchetti-Deschmann will complement with liquid oxidation reactions and Filipovic will perform gas sensing studies on our hybrids.

Supervisor

Research in Dominik Eder’s group focuses on the rational synthesis of novel energy materials, including nanocarbons, molecular and 2D inorganics, organic/inorganic hybrid materials and micro/mesoporous materials, utilizing modern wet-chemical, vapour/gas-phase techniques and a wide range of state-of-the-art spectroscopy, microscopy and thermal analysis techniques for characterization. Eder’s group engineer interfaces through hybridization, modifies the electronic structure through defect/dopant chemistry, and introduces large mesopores. Applied projects on energy, environment and medicine complement these fundamental studies.

Website

Group of Prof. Eder

Literature

  1. S. Naghdi, A. Cherevan, A. Giesriegl, R. Guillet-Nicolas, S. Biswas, T. Gupta, J. Wang, T. Haunold, B. C. Bayer, G. Rupprechter, M. C. Toroker, F. Kleitz and Dominik Eder Selective ligand removal to improve accessibility of active sites in hierarchical MOFs for heterogeneous photocatalysis Nat Commun 13, 282 (2022) DOI: https://doi.org/10.1038/s41467-021-27775-7 

  2. J. Wang, A. S. Cherevan, C. Hennecart, S. Naghdi, S. P. Nandan, T. Gupta and D. Eder Ti-based MOFs: New insights on the impact of ligand composition and hole scavengers on stability, charge separation and photocatalytic hydrogen evolution Applied Catalysis B: Environmental 283 (2021) DOI: https://doi.org/10.1016/j.apcatb.2020.119626

  3. Z. Zhang, Y. Zhu, H. Asakura, B. Zhang, J. Zhang, M. Zhou, Y. Han, T. Tanaka, A. Wang, T. Zhang, and N. Yan. Thermally stable single atom Pt/m-Al 2 O 3 for selective hydrogenation and CO oxidation. Nature Comm. 8, 16100 (2020). DOI: 10.1021/acscatal.9b05588.

  4. H. Rabl, S. N. Myakala, J. Rath, B. Fickl, J. S. Schubert, D. H. Apaydin and D. Eder Microwave-assisted synthesis of metal-organic chalcogenolate assemblies as electrocatalysts for syngas production Communications Chemistry 6, 43 (2023) DOI: https://doi.org/10.1038/s42004-023-00843-3

  5. G. M. Haselmann, B. Baumgartner, J. Wang, K. Wieland, T. Gupta, C. Herzig, A. Limbeck, B. Lendl and D. Eder In Situ Pt Photodeposition and Methanol Photooxidation on Pt/TiO2: Pt-Loading-Dependent Photocatalytic Reaction Pathways Studied by Liquid-Phase Infrared Spectroscopy ACS Catal. 10, 5 (2020) DOI: https://doi.org/10.1021/acscatal.9b05588