Abstract
CeO2-based catalysts as cathodes in solid oxide electrolysis cells (SOECs) have great potential for improving the storage of renewable electricity in the form of H2 via the water-splitting reaction (WSR). A key challenge to promote the WSR on CeO2 is facilitating the decomposition of stable surface hydroxides to form H2. Here, we use density functional theory to investigate the effect of Bi- and Pr- doping for the WSR on CeO2(111). We find that dopants influence the stability of hydridic H, which can be formed during the decomposition of hydroxyl to H2. By stabilizing hydridic H on Bi during the H2 formation step, Bi and Pr co-doped into ceria lower the barrier to H2 formation, enhancing the rate of WSR by 2–4 orders of magnitude compared to individually Pr-, Bi- or Gd-doped CeO2. We suggest co-doping as an effective strategy for improving the WSR in SOECs.
Highlights
Ceria-based materials are good mixed ionic and electronic conductors exposing a large ceriagas reaction interface and have been proposed as cathodes for the water-splitting reaction (WSR) in SOECs [1,2,3,4,5]
Investigations on water-associated reactions over ceria for H2 production have demonstrated that the fundamental reaction steps of the WSR on CeO2 include (a) the formation of oxygen vacancies (VO), (b) water adsorption and dissociation into hydroxyls or hydridic H-species if the hydroxyl surface coverage is beyond one monolayer, and (c) hydroxyl or hydride decomposition into H2 [1,4,5,6,7,8,9]
We systematically investigate the impact of Pr and Bi co-doping on the formation of VO and hydroxyls on CeO2 during the WSR and how the co-doping influences the reaction kinetics for H2 formation
Summary
This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Tiantian Wu, a Tejs Vegge, a,* Heine Anton Hansen a,* a Department of Energy Conversion and Storage, Technical University of Denmark, Anker Engelunds Vej Building 301, 2800 Kgs. Lyngby, Denmark
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
