%0 Journal Article
%A Wolf, Stephanie
%A Dittrich, Lucy
%A Nohl, Markus
%A Foit, Severin
%A Vinke, Izaak C.
%A de Haart, L. G. J.
%A Eichel, Rüdiger-A.
%T Boundary Investigation of High-Temperature Co-Electrolysis Towards Direct CO2 electrolysis
%J Journal of the Electrochemical Society
%V 103
%N 1
%@ 0013-4651
%C Bristol
%I IOP Publishing
%M FZJ-2021-05327
%P MA2021-03 215
%D 2022
%X In the temperature range of high temperature co-electrolysis of both steam and carbon dioxide, the reverse water-gas shift reaction (RWGS) takes place. Prior studies were conducted with a narrow gas composition range to investigate the role of RWGS during co-electrolysis. The results for steam electrolysis, CO2 electrolysis, and co-electrolysis caused different conclusions regarding the role of electrochemical CO2 and H2O conversion compared to RWGS during co-electrolysis. This work aims to resolve the role of CO2 conversion as part of RWGS in co-electrolysis. The boundary is characterized by AC and DC measurements over a broad gas composition range from CO2 electrolysis towards co-electrolysis with nearly 50%eq H2O. Especially, the electrochemical CO2 reduction and CO2 conversion in the RWGS are compared to clarify their role during co-electrolysis. The results revealed that gas composition determined the predominant reaction (H2O or CO2 reduction). The cell performance of co-electrolysis in the boundary region up to 5%eq H2O was similar to the performance of CO2 electrolysis. Up to 30%eq H2O, the performance increases with H2O concentration. Here, both CO2 and H2O electrolysis occur. Above 30%eq H2O, steam electrolysis and the RWGS reaction both dominate the co-electrolysis process.
%F PUB:(DE-HGF)16
%9 Journal Article
%U <Go to ISI:>//WOS:000776887600001
%R 10.1149/1945-7111/ac5e45
%U https://juser.fz-juelich.de/record/903678