An X-ray Spectroscopic Study of Co–Fe-Based Prussian Blue Analog Gels

• Published in: Bulletin of the Chemical Society of Japan Vol. 89; no. 12; pp. 1510 - 1517
• Main Authors: Hayashi, Hisashi, Abe, Hitoshi
• Format: Journal Article
• Language: English
• Published: Tokyo The Chemical Society of Japan 01.12.2016; Chemical Society of Japan
• Subjects: Banded structure; Cobalt; Gels; Iron cyanides; Oxidation; Pigments; Potassium ferricyanide; Tubes; X ray absorption; X ray fluorescence analysis; X-rays
• ISSN: 0009-2673; 1348-0634
• DOI: 10.1246/bcsj.20160293

We performed time-resolved X-ray fluorescence (XRF) and position-dependent X-ray absorption near-edge structure (XANES) spectroscopy on gels containing Co2+ and [Fe(CN)6]4−/[Fe(CN)6]3− ions. Sample tubes containing an agar gel mixed with 0.10 M CoCl2 solution and a water-glass gel mixed with 0.05 M K3[Fe(CN)6]/K4[Fe(CN)6] solution were prepared for the analyses. Dark-purple continuous (DPC) bands were observed in the water-glass gel of the two tubes. XRF results demonstrated that the DPC bands contained diffusive Co–Fe complexes. XANES results indicated that the Fe and Co local structures in the DPC bands were independent of the initial Fe oxidation states in [Fe(CN)6] and the measurement positions. It was found that the Fe local structure of the DPC bands was predominantly [Fe(CN)6]. The real-space multiple scattering calculations using FEFF 8.02 code suggested that Co–Fe-based Prussian blue analogs, of which the most likely local structure is Co(OC)4(NCFe)2, co-existed with [Co(H2O)6]2+ ions in the DPC bands.