Present status and prospects of operando measurement by atmospheric pressure hard X-ray photoelectron spectroscopy

Near ambient pressure photoemission spectroscopy that uses hard X-rays (NAP-HAXPES) has been performed at BL36XU in SPring-8 and HAXPES measurements under atmospheric pressure have been achieved using a small diameter aperture recently. The main target of measurement using this system has been the operando measurement of fuel cell electrodes. We measured Pt/C and Pt₃Co/C nanoparticle catalyst electrodes and obtained results on sulfur poisoning of the catalyst surface due to bias voltage changes. Recently, this system was moved to the upgraded HAXPES beamline 'HAXPES II' (BL46XU). The beamline is publicly available, and it is expected to be used by users not only in Japan but also all over the world to promote HAXPES measurements on various samples and environments. (author)