Advancing Soft X-ray Spectromicroscopy

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Over the next 5 years our research will enhance instrumentation, techniques and analysis software for two soft X-ray microscopy techniques - scanning transmission X-ray microscopy (STXM) and ptychography. We will (i) improve spatial resolution; (ii) provide more accurate spatially resolved chemical mapping in 2D (iii) devise methods to minimize radiation damage, including cryo-cooling and compressive sensing, a novel image acquisition method. We will use these improved capabilities to study (a) catalysts for CO2 electro-reduction under working conditions (operando); (b) mechanisms of intracellular biomineralization of single crystal magnetite by magnetotactic bacteria, and (c) sulfur speciation at the S 1s edge of syntropic marine bacterial-archae consortia which couple global sulfur and carbon cycles. Our long-term objectives are to develop new or improved soft x-ray microscopy techniques, and new classes of application. In the next 5 years we will: (1) complete development of ptychography (a method of enhancing spatial resolution in STXM) at the Canadian Light Source (CLS) and at Synchrotron Soleil in France; (2) carry out in situ and operando electrochemical STXM studies of CO2 electro-reduction catalysts; (3) help re-commission the CLS soft X-ray microscopy beamline after a new monochromator is installed in fall 2021, which will give more than an order of magnitude improvement in performance at energies in the 2000 - 3500 eV range. (4) carry out bio-geo-chemical studies with the new instrumentation, in particular use the S 1s edge (2460 eV) to analyze sulfur speciation in systems relevant to climate change. Scientifically this research program will provide important new knowledge in the energy materials sector. We will provide direct chemical characterization of new catalysts for CO2 electro-reduction, a method of recycling CO2. In the biological arena we will provide additional information on biomineralization of intracellular magnetite by magnetotactic bacteria, and a newly discovered protist species (first eukaryotic cell found which makes chains of intracellular magnetite). The improved STXM and ptychographic capabilities developed in this research will impact studies by many Canadian and international researchers, in particular those who wish to go beyond imaging and spectroscopy of static samples, to studies of how systems change under the influence of factors such as temperature, humidity, electrical currents, chemical reactions etc. Our instrumentation and technique development will be made available at CLS presented in publications and conferences and through aXis2000, the spectromicroscopy software package that I developed and continue to improve. By tackling specific projects which challenge current soft X-ray microscopy capabilities, my group's research significantly advances the field, and keeps the CLS soft X-ray microscopy facility, Canada's premier system for such studies, at the forefront.