Molecular-Scale Structure of Electrode–Electrolyte Interfaces: The Case of Platinum in Aqueous Sulfuric Acid

Journal Article · Mon Oct 29 00:00:00 EDT 2018 · Journal of the American Chemical Society

DOI:https://doi.org/10.1021/jacs.8b09743· OSTI ID:1543727

Wu, Cheng Hao  ^[1]; Pascal, Tod A.  ^[2]; Baskin, Artem ^[2]; Wang, Huixin ^[3]; Fang, Hai-Tao ^[3]; Liu, Yi-Sheng ^[4]; Lu, Yi-Hsien ^[5]; Guo, Jinghua  ^[6]; Prendergast, David ^[2]; Salmeron, Miquel B.  ^[7]

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1. Department of Chemistry, University of California, Berkeley, California 94720, United States; Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
2. The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
3. Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States; School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150080, P. R. China
4. The Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
5. Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
6. The Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States; Department of Chemistry and Chemical Biology, University of California, Santa Cruz, Santa Cruz, California 95064, United States
7. Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States; Department of Materials Science and Engineering, University of California, Berkeley, Berkeley, California 94720, United States

Knowledge of the molecular composition and electronic structure of electrified solid–liquid interfaces is key to understanding elemental processes in heterogeneous reactions. Using X-ray absorption spectroscopy in the interface-sensitive electron yield mode (EY-XAS), first-principles electronic structure calculations, and multiscale simulations, we determined the chemical composition of the interfacial region of a polycrystalline platinum electrode in contact with aqueous sulfuric acid solution at potentials between the hydrogen and oxygen evolution reactions. We found that between 0.7 and 1.3 V vs Ag/AgCl the electrical double layer (EDL) region comprises adsorbed sulfate ions with hydrated hydronium ions in the next layer. No evidence was found for bisulfate or Pt–O/Pt–OH species, which have very distinctive spectral signatures. In addition to resolving the long-standing issue of the EDL structure, our work establishes interface- and element-sensitive EY-XAS as a powerful spectroscopic tool for studying condensed phase, buried solid–liquid interfaces relevant to various electrochemical processes and devices.

• Research Organization: Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States). National Energy Research Scientific Computing Center (NERSC); Univ. of California, Oakland, CA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES)
• DOE Contract Number: AC02-05CH11231
• OSTI ID: 1543727
• Journal Information: Journal of the American Chemical Society, Vol. 140, Issue 47; ISSN 0002-7863
• Publisher: American Chemical Society (ACS)
• Country of Publication: United States
• Language: English

Related Subjects

Chemistry