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Jäker P, Aegerter D, Kyburz T, Städler R, Fonjallaz R, Detlefs B, Koziej D. Flow cell for operando X-ray photon-in-photon-out studies on photo-electrochemical thin film devices. Open Res Eur 2022; 2:74. [PMID: 37645301 PMCID: PMC10446061 DOI: 10.12688/openreseurope.14433.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 12/01/2022] [Indexed: 08/31/2023]
Abstract
Background: Photo-electro-chemical (PEC) water splitting represents a promising technology towards an artificial photosynthetic device but many fundamental electronic processes, which govern long-term stability and energetics, are not yet fully understood. X-ray absorption spectroscopy (XAS), and particularly its high energy resolution fluorescence-detected (HERFD) mode, emerges as a powerful tool to study photo-excited charge carrier behavior under operating conditions. The established thin film device architecture of PEC cells provides a well-defined measurement geometry, but it puts many constraints on conducting operando XAS experiments. It remains a challenge to establish a standardized thin film exchange procedure and concurrently record high-quality photoelectrochemical and X‑ray absorption spectroscopy data that is unperturbed by bubble formation. Here we address and overcome these instrumental limitations for photoelectrochemical operando HERFD-XAS. Methods: We constructed a novel operando photo-electro-chemical cell by computer numerical control milling, guided by the materials' X‑ray and visible light absorption properties to optimize signal detection. To test the cell's functionality, semiconducting thin film photoelectrodes have been fabricated via solution deposition and their photoelectrochemical responses under simulated solar light were studied using a commercial potentiostat in a three-electrode configuration during HERFD-XAS experiments at a synchrotron. Results: We demonstrate the cell's capabilities to measure and control potentiostatically and in open‑circuit, to detect X‑ray signals unperturbed by bubbles and to fluently exchange different thin film samples by collecting high-resolution Fe K-edge spectra of hematite ( α -Fe 2O 3) and ferrite thin film ( MFe 2O 4, M= Zn, Ni) photoelectrodes during water oxidation. Conclusions: Our cell establishes a measurement routine that will provide experimental access of photo-electro-chemical operando HERFD-XAS experiments to a broader scientific community, particularly due to the ease of sample exchange. We believe to enable a broad range of experiments which acquired fundamental insights will spur further photoelectrochemical research and commercialization of water splitting technologies.
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Affiliation(s)
- Philipp Jäker
- Department of Materials, Laboratory for Multifunctional Materials, ETH Zürich, Zurich, Vladimir-Prelog-Weg 5, 8093, Switzerland
- Institutes of Nanostructure and Solid State Physics, Center for Hybrid Nanostructures, University of Hamburg, Hamburg, Luruper Chaussee 149, 22607, Germany
| | - Dino Aegerter
- Department of Materials, Laboratory for Multifunctional Materials, ETH Zürich, Zurich, Vladimir-Prelog-Weg 5, 8093, Switzerland
| | - Till Kyburz
- Department of Materials, Laboratory for Multifunctional Materials, ETH Zürich, Zurich, Vladimir-Prelog-Weg 5, 8093, Switzerland
| | - Roman Städler
- Department of Materials, Laboratory for Multifunctional Materials, ETH Zürich, Zurich, Vladimir-Prelog-Weg 5, 8093, Switzerland
| | - Rea Fonjallaz
- Department of Materials, Laboratory for Multifunctional Materials, ETH Zürich, Zurich, Vladimir-Prelog-Weg 5, 8093, Switzerland
| | - Blanka Detlefs
- European Synchrotron Radiation Facility, Grenoble, 71 avenue des Martyrs, CS 40220, 38043, France
| | - Dorota Koziej
- Department of Materials, Laboratory for Multifunctional Materials, ETH Zürich, Zurich, Vladimir-Prelog-Weg 5, 8093, Switzerland
- Institutes of Nanostructure and Solid State Physics, Center for Hybrid Nanostructures, University of Hamburg, Hamburg, Luruper Chaussee 149, 22607, Germany
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James AK, Dolgova NV, Nehzati S, Korbas M, Cotelesage JJH, Sokaras D, Kroll T, O’Donoghue JL, Watson GE, Myers GJ, Pickering IJ, George GN. Molecular Fates of Organometallic Mercury in Human Brain. ACS Chem Neurosci 2022; 13:1756-1768. [PMID: 35543423 PMCID: PMC9977140 DOI: 10.1021/acschemneuro.2c00166] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Mercury is ubiquitous in the environment, with rising levels due to pollution and climate change being a current global concern. Many mercury compounds are notorious for their toxicity, with the potential of organometallic mercury compounds for devastating effects on the structures and functions of the central nervous system being of particular concern. Chronic exposure of human populations to low levels of methylmercury compounds occurs through consumption of fish and other seafood, although the health consequences, if any, from this exposure remain controversial. We have used high energy resolution fluorescence detected X-ray absorption spectroscopy to determine the speciation of mercury and selenium in human brain tissue. We show that the molecular fate of mercury differs dramatically between individuals who suffered acute organometallic mercury exposure (poisoning) and individuals with chronic low-level exposure from a diet rich in marine fish. For long-term low-level methylmercury exposure from fish consumption, mercury speciation in brain tissue shows methylmercury coordinated to an aliphatic thiolate, resembling the coordination environment observed in marine fish. In marked contrast, for short-term high-level exposure, we observe the presence of biologically less available mercuric selenide deposits, confirmed by X-ray fluorescence imaging, as well as mercury(II)-bis-thiolate complexes, which may be signatures of severe poisoning in humans. These differences between low-level and high-level exposures challenge the relevance of studies involving acute exposure as a proxy for low-level chronic exposure.
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Affiliation(s)
- Ashley K. James
- Toxicology Centre, 44 Campus Drive, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5B3, Canada.,Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada
| | - Natalia V. Dolgova
- Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada
| | - Susan Nehzati
- Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada
| | - Malgorzata Korbas
- Canadian Light Source, 44 Innovation Blvd, Saskatoon, Saskatchewan S7N 2V3, Canada
| | - Julien J. H. Cotelesage
- Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada
| | - Dimosthenis Sokaras
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, California 94025, USA
| | - Thomas Kroll
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, California 94025, USA
| | - John L. O’Donoghue
- Department of Environmental Medicine, School of Medicine and Dentistry, University of Rochester, Rochester, New York 14642, USA
| | - Gene E. Watson
- Department of Environmental Medicine, School of Medicine and Dentistry, University of Rochester, Rochester, New York 14642, USA.,Eastman Institute for Oral Health, School of Medicine and Dentistry, University of Rochester, Rochester, New York 14642, USA
| | - Gary J. Myers
- Department of Environmental Medicine, School of Medicine and Dentistry, University of Rochester, Rochester, New York 14642, USA.,Departments of Neurology and Pediatrics, School of Medicine and Dentistry, University of Rochester, Rochester, New York 14642, USA
| | - Ingrid J. Pickering
- Toxicology Centre, 44 Campus Drive, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5B3, Canada.,Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada.,Department of Chemistry, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5C9, Canada.,Corresponding Authors: Ingrid J. Pickering – Department of Geological Sciences, Toxicology Centre, and Department of Chemistry, University of Saskatchewan, Saskatoon S7N 5E2, Canada; , Graham N. George – Department of Geological Sciences, Toxicology Centre, and Department of Chemistry, University of Saskatchewan, Saskatoon S7N 5E2, Canada;
| | - Graham N. George
- Toxicology Centre, 44 Campus Drive, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5B3, Canada.,Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada.,Department of Chemistry, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5C9, Canada.,Corresponding Authors: Ingrid J. Pickering – Department of Geological Sciences, Toxicology Centre, and Department of Chemistry, University of Saskatchewan, Saskatoon S7N 5E2, Canada; , Graham N. George – Department of Geological Sciences, Toxicology Centre, and Department of Chemistry, University of Saskatchewan, Saskatoon S7N 5E2, Canada;
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