Tuning the Co Oxidation State in Ba0.5Sr0.5Co0.8Fe0.2O3-δ by Flame Spray Synthesis Towards High Oxygen Evolution Reaction Activity

Catalysts

ThomasJ. Schmidt¹  Maarten Nachtegaal¹  Dino Aegerter¹  Emiliana Fabbri¹  AdamH. Clark¹  Mario Borlaf²  Thomas Graule² 

[1] Energy and Environment Research Division, Paul Scherrer Institute PSI, Forschungsstrasse 111, CH-5232 Villigen PSI, Switzerland;Laboratory for High Performance Ceramics, Empa-Swiss Federal Laboratories for Materials Science and Technology, CH-8600 Dübendorf, Switzerland;

关键词: alkaline water electrolyzer;    water splitting;    oxygen evolution reaction;    perovskite-type oxide;    flame spray synthesis;    rotating disc electrode;   

DOI  :  10.3390/catal10090984

来源: DOAJ

【 摘 要 】

The perovskite-type oxide Ba_0.5Sr_0.5Co_0.8Fe_0.2O_3-δ (BSCF) is known as a highly active and stable oxygen evolution reaction (OER) electrocatalyst composited out of non-noble metals. The possibility of using the scalable flame spray synthesis (FSS) technique for the production of BSCF nanoparticles intensified the interest in this material for a future application in an alkaline water electrolyzer. A possible scale-up would require the optimization of the synthesis parameters to maximize the production rate. To further understand the influence of the synthesis parameters of the tunable FSS on the OER activity of BSCF, a systematic study was carried out by producing BSCF with different total metal concentrations (C_TM), flow rates of the precursor solution (FR_PS) and of the dispersion gas (FR_DG). This study reveals that all three parameters have a direct impact on the OER activity of BSCF—measured in a rotating disc electrode (RDE) setup—due to the controllability of the initial Co and Fe oxidation state—indicated by X-ray absorption spectroscopy (XAS) measurements—and with that also of the oxygen vacancy concentration in the as-synthesized BSCF. This controllability enables the optimization of the OER activity of BSCF and emphasizes the importance of having Co in a lower initial oxidation state for reaching a high electrocatalytic performance.

【 授权许可】

Unknown