Rational design of CO2 electroreduction cathode via in situ electrochemical phase transition

CO2 electroreduction reaction (CO2RR), combined with solid oxide electrolysis cells (SOECs), is a feasible technology for the storage of renewable electric energy, while its development is limited by the catalytic activity and stability on cathodes. Here, a novel garnet oxide (Gd3Fe5O12) cathode is designed, where the garnet oxide is converted to perovskite oxide and iron via in situ electrochemical phase transition during CO2 electroreduction, resulting in high activity with Faradaic efficiency close to 100% and great stability over 1000 h galvanostatic test. A variety of experimental characterizations and density functional theory calculations indicate that in situ exsolved Fe clusters can effectively enhance the adsorption energies of intermediates and lowering the CO2 dissociation barriers. Microkinetic modelling confirms that CO2RR goes through a dissociative adsorption mechanism and the electronic transfer for CO2 dissociation is the rate-determining step. (C) 2021 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by ELSEVIER B.V. and Science Press. All rights reserved.

Automated summary

A novel garnet oxide cathode was designed for CO2 electroreduction, showing high activity and stability. Experimental characterizations and DFT calculations indicate that exsolved Fe clusters enhance intermediate adsorption and lower CO2 dissociation barriers. Microkinetic modeling confirms a dissociative adsorption mechanism for CO2RR with electronic transfer as the rate-determining step.