Understanding the origin of high oxygen evolution reaction activity in the high Sr-doped perovskite

Publication date: April 2020Source: Chinese Journal of Catalysis, Volume 41, Issue 4Author(s): Sanzhao Song, Jing Zhou, Jian Sun, Shiyu Zhang, Xiao Lin, Zhiwei Hu, Jun Hu, Linjuan Zhang, Jian-Qiang WangEffective electrocatalysis is crucial for enhancing the efficiency of water splitting to obtain clean fuels. Herein, we report a system of interesting and high-performance Sr-doped perovskite electrocatalysts with porous structures, obtained via a facile molten salt method and applied in the oxygen evolution reaction (OER). With increasing the Sr content, the valence states of Co and Fe ions do not clearly increase, according to the Co-L2,3 and Fe-L2,3 as well as the Co-K and the Fe-K X-ray absorption spectroscopy, whereas doped holes are clearly observed in the O-K edge. High-resolution transmission electron microscopy indicates the appearance of an amorphous layer after the electrochemical reaction. We conclude that the formation of the amorphous layer at the surface, induced by Sr doping, is crucial for achieving high OER activity, and we offer insights into the self-reconstruction of the OER catalyst.Graphical AbstractSr-doping leads to oxygen vacancies and the formation of an amorphous layer, whose thickness increases with the Sr content. The amorphous layer is responsible for the high oxygen evolution reaction activity.
Source: Chinese Journal of Catalysis - Category: Chemistry Source Type: research