Even though the 26th UN Climate Change Conference of the Parties (COP26) concluded in a storm of controversies, the world's growing energy crisis and environmental pollution (e.g., the global 36.7 billion metric tons of CO2 emission per year) are realities that scientists and human society have to confront. As a result, figuring out how to employ low-carbon technologies, such as electrochemical technologies, to achieve energy conversion and systematic carbon reduction is becoming increasingly critical.
Due to its high energy efficiency (>75%) and high temperature toxicity resistance potential, the solid oxide electrolysis cell (SOEC) has been gradually applied in the process of electrolysis of C1 molecules such as carbon dioxide (CO2) and methane (CH4) into value-added renewable fuels such as syngas, ethylene, and others. Many significant progresses have been achieved in the past decades. However, the unclear reaction mechanism, poor durability, and the prospect of industrialization are calling for more efforts on the development of SOEC-based C1 molecules conversion.
In a new review published in Chinese Journal of Catalysis (DOI: 10.1016/S1872-2067(21)63838-X), the research team led by Prof. Gengfeng Zheng from Fudan University reviewed the progresses in this field. Based on an introduction of SOEC technology, the recent three years' work on C1-to-fuels conversion based on solid oxide electrolysis cell is summarized.
The following three reaction systems are mainly introduced from the perspectives of system characteristics and research challenges: (1) Carbon dioxide electrolysis system and characteristics, including the recent progress, the advantages and disadvantages of high temperature carbon dioxide electrolysis; (2) Carbon dioxide/steam co-electrolysis system and its characteristics, including a series of catalyst materials and mechanism researches; (3) Methane conversion system and its characteristics, including recent work, the challenges and prospects in the future of methane system.
Moreover, authors also share their thoughts on the future research directions toward SOEC-based C1 conversion. In detail, they proposed the following four aspects: (1) cost and feasibility analysis; (2) theoretical calculations and operando characterizations; (3) triple-phase-boundary modification and materials research; and (4) expansion of new reactants and systems. The content of the review is specific, and mainly focuses on the system and strategic research on SOEC-based C1-to-fuels conversion, which can be a good guide for those interested in C1 chemistry and electrochemistry.
This work was supported by the National Key Research and Development Program of China (2017YFA0206901, 2018YFA0209401), the National Science Foundation of China (22025502, 21975051, 21773036), the Science and Technology Commission of Shanghai Municipality (19XD1420400), and the Innovation Program of Shanghai Municipal Education Commission (2019-01-07-00-07-E00045).