Zhou Fangping, Zhao Zhao, Xu Ming, Wang Ting, Yang Huiru, Wang Rong, Wang Jiahui, Li Haibo, Feng Ming
Key Laboratory of Functional Materials Physics and Chemistry of the Ministry of Education, Jilin Normal University, Changchun, 130103, P. R. China.
Chemistry. 2022 Mar 7;28(14):e202104157. doi: 10.1002/chem.202104157. Epub 2022 Feb 11.
Perovskite is a promising non-noble catalyst and has been widely investigated for the electrochemical oxygen evolution reaction (OER). However, there is still serious lack of valid approaches to further enhance their catalytic performance. Herein, we propose a spin state modulation strategy to improve the OER electrocatalytic activity of typical perovskite material of LaCoO . Specifically, the electronic configuration transition was realized by a simple high temperature thermal reduction process. M-H hysteresis loop results reveal that the reduction treatment can produce more unpaired electrons in 3d orbit by promoting the electron transitions of Co from low spin state to high spin state, and thus lead to the increase of the spin polarization. Electrochemical measurements show that the catalytic performance of LaCoO is strongly dependent on its electronic configuration. With the optimized reduction treatment, the overpotential for the OER process in 0.5 M KOH electrolyte solution at 10 mA cm current density was 396 mV, significantly lower than that of the original state. Furthermore, it can mediate efficient OER with an overpotential of 383 mV under an external magnetic field, which is attributed to the appropriate electron filling. Our results show that electron spin state regulation is a new way to boost the OER electrocatalytic activity.
钙钛矿是一种很有前景的非贵金属催化剂，已被广泛研究用于电化学析氧反应（OER）。然而，仍然严重缺乏进一步提高其催化性能的有效方法。在此，我们提出一种自旋态调制策略来提高典型钙钛矿材料LaCoO₃的OER电催化活性。具体而言，通过简单的高温热还原过程实现了电子构型转变。M-H磁滞回线结果表明，还原处理可通过促进Co从低自旋态到高自旋态的电子跃迁，在3d轨道中产生更多未成对电子，从而导致自旋极化增加。电化学测量表明，LaCoO₃的催化性能强烈依赖于其电子构型。经过优化的还原处理后，在0.5 M KOH电解液中，10 mA cm⁻²电流密度下OER过程的过电位为396 mV，明显低于原始状态。此外，在外部磁场下，它可以介导高效的OER，过电位为383 mV，这归因于适当的电子填充。我们的结果表明，电子自旋态调控是提高OER电催化活性的一种新方法。
