The hexagonal perovskite BaNiO3, prepared via non-ceramic approaches, is known to act as a good catalyst for the oxygen-evolution reaction (OER) in alkaline media. Here we report our observation that BaNiO3 synthesized via KOH flux growth and high O2 pressure ceramic synthesis have different magnetic properties. We show that this is because the KOH flux-grown crystals made in open-air are actually a hydroxide-containing form of BaNiO3 that can be dried upon annealing in O2 flow. This work not only unveils a previously unknown aspect of the BaNiO3 OER catalyst and offers some insights into the underlying mechanism, but also suggests that hydroxide ions may be present in other hexagonal perovskite oxides prepared in wet conditions.
@article{arxiv.2306.05488,
title = {Hidden Hydroxides in KOH-Grown BaNiO3 Crystals: A Potential Link to Their Catalytic Behavior},
author = {Lun Jin and Haozhe Wang and Xianghan Xu and Danrui Ni and Chen Yang and Yu-Chieh Ku and Cheng-En Liu and Chang-Yang Kuo and Chun-Fu Chang and Raimundas Sereika and Wenli Bi and Weiwei Xie and Robert. J. Cava},
journal= {arXiv preprint arXiv:2306.05488},
year = {2023}
}