Details

Autor(en) / Beteiligte

• Teliska, Maggie
• Murthi, Vivek S
• Mukerjee, Sanjeev
• Ramaker, David E

Titel

Site-Specific vs Specific Adsorption of Anions on Pt and Pt-Based Alloys

Ist Teil von

• Journal of physical chemistry. C, 2007-07, Vol.111 (26), p.9267-9274

Ort / Verlag

American Chemical Society

Erscheinungsjahr

2007

Link zum Volltext

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• X-ray absorption spectroscopy (XAS) is utilized in situ to gain new insights into the electronic and chemical interactions of anions specifically adsorbed on Pt/C. A novel difference methodology was utilized, along with full-multiple scattering calculations using the FEFF8 code, to interpret the X-ray absorption near edge structure (XANES). Significant direct contact (“specific”) anion adsorption occurs in 1 M H2SO4 and 6 M TFMSA, while it does not in 1 M HClO4 and 1 M TFMSA. This specific anion adsorption significantly hinders O(H) chemisorption, particularly formation of subsurface O, causes the Pt nanoparticle to become more round, and weakens the Pt−Pt bonding at the surface. The specific anion adsorption becomes site-specific only after lateral interactions from other chemisorbed species such as OH on the surface force the anions to adsorb into specific sites. Alloying has a profound effect on the strength of the anion adsorption and whether site-specific or just specific adsorption occurs.