2019 Volume 62 Issue 1 Pages 33-38
Near ambient and ambient pressure photoelectron spectroscopy measurement that uses with hard X-rays (NAP- and AP-HAXPES) were conducted at the BL36XU of SPring-8. To increase the pressure limit in the NAP-HAXPES measurement, we replaced the front cone with our home-made one with an aperture diameter of 30 µm from a standard 300 µm size aperture. By using this equipment, a photoelectron spectrum of the gold foil under atmospheric pressure was successfully measured. In this paper, we summarize the investigations of the electronic states of platinum nanoparticles in a polymer electrolyte fuel cell (PEFC) under the voltage operating conditions using the NAP-HAXPES system. The Pt 3d spectra of the Pt/C cathode catalysts clearly show different behaviors with increasing voltage compared with decreasing voltage. Subsequently, we found the electric potential variation of the electrode in a PEFC by non-contact measurements based on the kinetic energy shift in component potential.