Researchers Achieve Efficient CO2 Electrolysis in Solid Oxide Electrolysis Cell

Solid oxide electrolysis cell (SOEC) holds great potential when it comes to conversion of CO₂ and renewable clean electricity energy storage. It has the ability to convert CO₂ and H₂O concurrently into syngas or hydrocarbon fuel at the cathode and generate high purity O₂ at the anode.

Perovskite-type oxides offer the benefit of outstanding redox stability, carbon deposition resistance and doping ability. But the application of perovskite electrodes is restricted as a result of their inadequate electrocatalytic activity.

In recent times, efficient and stable CO₂ electrolysis in SOEC was achieved by scientists headed by Professor Guoxiong Wang and Professor Xinhe Bao from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences and their colleagues.

They discovered that redox cycle manipulations supported the exsolution of high-density metal/perovskite interfaces, enhancing the performance and stability of CO₂ electrolysis. This study was reported in the Nature Communications journal on September 27^th, 2021.

The Ru-doped Sr₂Fe₁.₄Ru_0.1Mo_0.5O_6−δ (SFRuM) double perovskite was prepared by the researchers. They discovered that the repeated redox manipulations boosted the exsolution of RuFe alloy nanoparticles from 5900 μm⁻² to 22,680 μm⁻², where the mean particle size ranged between 2.2 and 2.9 nm. Thus, this helps control the density of the RuFe@SFRuM interfaces.

The researchers combined in situ atmosphere electron microscopy, electron energy loss spectroscopy, and elemental maps to unravel the formation and regeneration mechanism of the RuFe@SFRuM interface under oxidizing and reducing atmosphere.

The enrichment in Ru species on the surface can promote the exsolution of high-density RuFe@SFRuM interfaces.

Guoxiong Wang, Professor, Dalian Institute of Chemical Physics, Chinese Academy of Sciences

In addition to in situ atmosphere electron microscopy, electrochemical impedance spectroscopy and density functional theory calculations verified that the RuFe@SFRuM interface supported CO₂ adsorption and activation.

The RuFe@SFRuM cathode showed a 74.6% increase in current density for CO₂ electrolysis at 1.2 V and 800 °C when compared with the SFRuM cathode. Also, it displayed high stability of CO₂ electrolysis for 1000 hours.

This work was financially supported by the National Natural Science Foundation of China, the National Key Research and Development Program, and the Youth Innovation Promotion Association of the Chinese Academy of Sciences.

Journal Reference:

Lv, H., et al. (2021) Promoting exsolution of RuFe alloy nanoparticles on Sr₂Fe₁.₄Ru_0.1Mo_0.5 O_6−δ via repeated redox manipulations for CO₂ electrolysis. Nature Communications. doi.org/10.1038/s41467-021-26001-8.