Ultrathin Silicon Oxide Overlayers Enable Selective Oxygen Evolution from Acidic and Unbuffered pH-Neutral Seawater

ACS Catalysis, vol. 11, pp. 1316–1330

Abstract

Seawater electrolysis is an attractive approach for producing clean hydrogen fuel in scenarios where freshwater is scarce and renewable electricity is abundant. However, chloride ions (Cl – ) in seawater can accelerate electrode corrosion and participate in the undesirable chlorine evolution reaction (CER). This problem is especially acute in acidic conditions that naturally arise at the anode as a result of the desired oxygen evolution reaction (OER). Herein, we demonstrate that ultrathin silicon oxide (SiO x ) overlayers on model platinum anodes are highly effective at suppressing the CER in the presence of 0.6 M Cl – in both acidic and unbuffered pH-neutral electrolytes by blocking the transport of Cl – to the catalytically active buried interface while allowing the desired oxygen evolution reaction (OER) to occur there. The permeability of Cl – in SiO x overlayers is 3 orders of magnitude less than that of Cl – in a conventional salt-selective membrane used in reverse osmosis desalination. The overlayers also exhibit robust stability over 12 h in chronoamperometry tests at moderate overpotentials. SiO x overlayers demonstrate a promising step toward achieving selective and stable seawater electrolysis without the need to adjust the pH of the electrolyte.

Authors 7

1. Amar A. Bhardwaj

   Columbia University

   Affiliation as printed

   Department of Chemical Engineering, Columbia Electrochemical Engineering Center, Lenfest Center for Sustainable Energy, Columbia University in the City of New York, 500 West 120th Street, New York, New York 10027, United States

2. Johannes G. Vos Aachen

   Leiden University

   Affiliation as printed

   Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands

3. Marissa Beatty

   Columbia University

   Affiliation as printed

   Department of Chemical Engineering, Columbia Electrochemical Engineering Center, Lenfest Center for Sustainable Energy, Columbia University in the City of New York, 500 West 120th Street, New York, New York 10027, United States

4. Amanda F. Baxter

   Columbia University

   Affiliation as printed

   Department of Chemical Engineering, Columbia Electrochemical Engineering Center, Lenfest Center for Sustainable Energy, Columbia University in the City of New York, 500 West 120th Street, New York, New York 10027, United States

5. Marc T. M. Koper Aachen

   Leiden University

   Affiliation as printed

   Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands

6. Ngai Yin Yip

   Columbia University

   Affiliation as printed

   Department of Earth and Environmental Engineering, Columbia Water Center, Columbia University in the City of New York, 500 West 120th Street, New York, New York 10027, United States

7. Daniel V. Esposito corresponding

   Columbia University

   Affiliation as printed

   Department of Chemical Engineering, Columbia Electrochemical Engineering Center, Lenfest Center for Sustainable Energy, Columbia University in the City of New York, 500 West 120th Street, New York, New York 10027, United States