Reactions and mass transport in high temperature co-electrolysis of steam/CO2 mixtures for syngas production

Si Won Kim, Hyoungchul Kim, Kyung Joong Yoon, Jong Ho Lee, Byung Kook Kim, Wonjoon Choi, Jong Heun Lee, Jongsup Hong

Research output: Contribution to journalArticlepeer-review

63 Citations (Scopus)


High temperature co-electrolysis of steam/CO2 mixtures using solid oxide cells has been proposed as a promising technology to mitigate climate change and power fluctuation of renewable energy. To make it viable, it is essential to control the complex reacting environment in their fuel electrode. In this study, dominant reaction pathway and species transport taking place in the fuel electrode and their effect on the cell performance are elucidated. Results show that steam is a primary reactant in electrolysis, and CO2 contributes to the electrochemical performance subsequently in addition to the effect of steam. CO2 reduction is predominantly governed by thermochemical reactions, whose influence to the electrochemical performance is evident near limiting currents. Chemical kinetics and mass transport play a significant role in co-electrolysis, given that the reduction reactions and diffusion of steam/CO2 mixtures are slow. The characteristic time scales determined by the kinetics, diffusion and materials dictate the cell performance and product compositions. The fuel electrode design should account for microstructure and catalysts for steam electrolysis and thermochemical CO2 reduction in order to optimize syngas production and store electrical energy effectively and efficiently. Syngas yield and selectivity are discussed, showing that they are substantially influenced by operating conditions, fuel electrode materials and its microstructure.

Original languageEnglish
Pages (from-to)630-639
Number of pages10
JournalJournal of Power Sources
Publication statusPublished - 2015 Apr 15

Bibliographical note

Funding Information:
This research was financially supported by the Institutional Research Program of the Korea Institute of Science and Technology ( 2E24691 ) and the Fusion Research Program for Green Technologies through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT & Planning ( 2N39090 ).

Publisher Copyright:
© 2015 Elsevier B.V. All rights reserved.


  • CO reduction
  • CO utilization
  • Co-electrolysis
  • Solid oxide electrolysis cell
  • Syngas production

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment
  • Energy Engineering and Power Technology
  • Physical and Theoretical Chemistry
  • Electrical and Electronic Engineering


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