Elucidating the Complex Oxidation Behavior of Aqueous HPO on Pt Electrodes via Tender X-ray Absorption Near-Edge Structure Spectroscopy at the P -Edge.

tender X-ray absorption near-edge structure (XANES) spectroscopy at the P -edge was utilized to investigate the oxidation mechanism of aqueous HPO on Pt electrodes under various conditions relevant to high-temperature polymer electrolyte membrane fuel cell (HT-PEMFC) applications. XANES and electrochemical analysis were conducted under different tender X-ray irradiation doses, revealing that intense radiation induces the oxidation of aqueous HPO via HO yielding HPO and H. A broadly applicable experimental procedure was successfully developed to suppress these undesirable radiation-induced effects, enabling a more accurate determination of the aqueous HPO oxidation mechanism.

Oxidation of Aqueous Phosphorous Acid Electrolyte in Contact with Pt Studied by X-ray Photoemission Spectroscopy.

The oxidation of the aqueous HPO in contact with Pt was investigated for a fundamental understanding of the Pt/aqueous HPO interaction with the goal of providing a comprehensive basis for the further optimization of high-temperature polymer electrolyte membrane fuel cells (HT-PEMFCs). Ion-exchange chromatography (IEC) experiments suggested that in ambient conditions, Pt catalyzes HPO oxidation to HPO with HO. X-ray photoelectron spectroscopy (XPS) on different substrates, including Au and Pt, previously treated in HPO solutions was conducted to determine the catalytic abilities of selected metals toward HPO oxidation.