Decoupled hydrogen and oxygen evolution by a two-step electrochemical–chemical cycle for efficient overall water splitting

Hen Dotan, Avigail Landman, Stafford W. Sheehan, Kirtiman Deo Malviya, Gennady E. Shter, Daniel A. Grave, Ziv Arzi, Nachshon Yehudai, Manar Halabi, Netta Gal, Noam Hadari, Coral Cohen, Avner Rothschild, Gideon S. Grader

Research output: Contribution to journalArticlepeer-review

146 Scopus citations

Abstract

Electrolytic hydrogen production faces technological challenges to improve its efficiency, economic value and potential for global integration. In conventional water electrolysis, the water oxidation and reduction reactions are coupled in both time and space, as they occur simultaneously at an anode and a cathode in the same cell. This introduces challenges, such as product separation, and sets strict constraints on material selection and process conditions. Here, we decouple these reactions by dividing the process into two steps: an electrochemical step that reduces water at the cathode and oxidizes the anode, followed by a spontaneous chemical step that is driven faster at higher temperature, which reduces the anode back to its initial state by oxidizing water. This enables overall water splitting at average cell voltages of 1.44–1.60 V with nominal current densities of 10–200 mA cm−2 in a membrane-free, two-electrode cell. This allows us to produce hydrogen at low voltages in a simple, cyclic process with high efficiency, robustness, safety and scale-up potential.

Original languageEnglish
Pages (from-to)786-795
Number of pages10
JournalNature Energy
Volume4
Issue number9
DOIs
StatePublished - 1 Sep 2019
Externally publishedYes

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Renewable Energy, Sustainability and the Environment
  • Fuel Technology
  • Energy Engineering and Power Technology

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