• Energy Research

To investigate multi-boson peaks (multi-BP), terahertz time-domain spectroscopy was performed on amorphous silicon monoxide (a-SiO), which exhibits unusual disproportion in the nanoscale region where the SiO 2 and Si regions are separated. In the resulting THz spectrum, the BP was observed at 2.4 THz, as a broad asymmetric peak, and the BP frequency was evidently higher than that of silica glass. The results suggest that the higher BP frequency of a-SiO in the infrared spectrum originates from the a-Si cluster region.

The structural kinetics of surface events on a Pt3Co/C cathode catalyst in a polymer electrolyte fuel cell (PEFC) was investigated by operando time-resolved X-ray absorption fine structure (XAFS) with a time resolution of 500 ms. The rate constants of electrochemical reactions, the changes in charge density on Pt, and the changes in the local coordination structures of the Pt3Co alloy catalyst in the PEFC were successfully evaluated during fuel-cell voltage-operating processes. Significant time lags were observed between the electrochemical reactions and the structural changes in the Pt3Co alloy catalyst. The rate constants of all the surface events on the Pt3Co/C catalyst were significantly higher than those on the Pt/C catalyst, suggesting the advantageous behaviors (cell performance and catalyst durability) on the Pt3Co alloy cathode catalyst.