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

Abstract

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.

Authors:

Wu, Cheng Hao  ^[1];

• Search DOE PAGES for author "Wu, Cheng Hao"
• Search DOE PAGES for ORCID "0000-0002-6515-0988"

Pascal, Tod A.  ^[2];

• Search DOE PAGES for author "Pascal, Tod A."
• Search DOE PAGES for ORCID "0000-0003-2096-1143"

Baskin, Artem ^[2]; Wang, Huixin ^[3]; Fang, Hai-Tao ^[3]; Liu, Yi-Sheng ^[2]; Lu, Yi-Hsien ^[4]; Guo, Jinghua  ^[5];

• Search DOE PAGES for author "Guo, Jinghua"
• Search DOE PAGES for ORCID "0000-0002-8576-2172"

Prendergast, David ^[2]; Salmeron, Miquel B.  ^[6]

• Search DOE PAGES for author "Salmeron, Miquel B."
• Search DOE PAGES for ORCID "0000-0002-2887-8128"

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+ Show Author Affiliations

1. Univ. of California, Berkeley, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
2. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
3. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Harbin Inst. of Technology (China)
4. Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
5. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Univ. of California, Santa Cruz, CA (United States)
6. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Univ. of California, Berkeley, CA (United States)

Publication Date:

Mon Oct 29 00:00:00 EDT 2018

Research Org.:

Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Materials Sciences & Engineering Division

OSTI Identifier:

1604655

Grant/Contract Number:  

AC02-05CH11231

Resource Type:

Accepted Manuscript

Journal Name:

Journal of the American Chemical Society

Additional Journal Information:

Journal Volume: 140; Journal Issue: 47; Journal ID: ISSN 0002-7863

Publisher:

American Chemical Society (ACS)

Country of Publication:

United States

Language:

English

Subject:

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; interfaces; platinum; anions; molecules; ions