Stable oxide electrolysis cells (SOECs) present a sensible answer for direct conversion of CO2 to chemical substances; nevertheless, an in-depth mechanistic understanding of the dynamic reconstruction of energetic websites for perovskite cathodes throughout CO2 electrolysis stays an ideal problem.
In a examine led by Dr. Houfu Lv, Prof. Guoxiong Wang and Prof. Xinhe Bao (Dalian Institute of Chemical Physics, Chinese language Academy of Sciences), the workforce establish that iridium-doped Sr2Fe1.45Ir0.05Mo0.5O6-δ (SFIrM) perovskite shows a dynamic electrochemical reconstruction characteristic throughout CO2 electrolysis with considerable exsolution of extremely dispersed IrFe alloy nanoparticles (NPs) on the SFIrM floor, which is nicely investigated utilizing in situ electrochemical X-ray diffraction (XRD), near-ambient stress X-ray photoelectron spectroscopy (NAP-XPS), and X-ray absorption spectroscopy (XAS).
In the course of the electrochemical reconstruction and activation course of beneath a continuing voltage mode at 1.0 V for ~4 000 s, the present density steadily elevated and at last approached a gradual state.
The exsolved IrFe alloy NPs show excessive dispersion with a median diameter of ~1.0 nm and a density above 80 000 μm-2 on the SFIrM floor. Furthermore, the activation time was lowered quickly with growing utilized voltage (fixed voltage: 1.2 V, activation time: inside 250 s), with comparable particle dimension and density of the exsolved steel NPs throughout CO2 electrolysis.
As well as, in situ NAP-XPS measurements have been employed to watch their catalytic course of throughout CO2 electrolysis to disclose the intrinsic response mechanism. Upon software of electrochemical polarization, a broader peak appeared at ca. 290 eV within the C 1s spectra, which may very well be attributed to carbonate species and was likely decisive for CO2 electrolysis.
The height space of carbonate species on the Sr2Fe1.5Mo0.5O6-δ (SFM) cathode was weaker than that on the SFIrM cathode. The improved carbonate intermediate species sign confirmed that the in situ reconstructed IrFe@SFIrM interfaces facilitated CO2 adsorption and activation. IrFe@SFIrM interfaces have been thus proposed because the catalytically energetic websites that dedicated to the next CO2 electrolysis efficiency than SFM.
The preliminary exsolved IrFe alloy NPs may very well be re-dispersed sufficiently into smaller nanoclusters through a quick oxidation therapy in air. IrFe alloy NPs have been regenerated when the utilized voltage was switched on once more, and the looks of the intermediate carbonate peak may very well be additional obtained. The oxidative re-dispersion technique may effectively enhance the soundness by delaying particle aggregation.
The analysis is printed within the journal Nationwide Science Evaluation.
Yuxiang Shen et al, In situ electrochemical reconstruction of Sr2Fe1.45Ir0.05Mo0.5O6-δ perovskite cathode for CO2 electrolysis in stable oxide electrolysis cells, Nationwide Science Evaluation (2023). DOI: 10.1093/nsr/nwad078
In situ investigation of the structure-activity correlation for carbon dioxide electrolysis in SOECs (2023, Might 25)
retrieved 25 Might 2023
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