在电化学诱导的 δ-MnO2上发现了水氧化的活性位点:旋转到层相转的作用
1Collaborative Innovation Center of Chemistry for Energy Material, Key Laboratory of Computational Physical Science (Ministry of Education), Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Department of Chemistry, Fudan University , Shanghai 200433, China.
Journal of the American Chemical Society
|January 16, 2018
概括
研究人员发现了一种新型,高活性的氧化 (MnOx) 催化剂,用于人工分水. 一个特定的缺陷位,模仿大自然的光系统II,显著提高氧化演化反应 (OER) 的效率.
科学领域:
- 材料科学
- 电化学
- 催化剂
背景情况:
- 氧化物 (MnOx) 被广泛研究为人工水分裂的催化剂,旨在复制自然光合作用.
- 氧化演化反应 (OER) 的最活跃的MnOx催化剂通常来自旋转结构,在现场形成 δ-MnO2层,但它们的活跃位点仍然不明.
- 了解MnOx转换的原子级机制和识别活性位点对于设计高效的水分裂催化剂至关重要.
研究的目的:
- 阐明在水性电解质中旋转到层 Mn3O4的固相过渡的原子层机制.
- 确定MnOx催化剂中高OER活性的特定活性位点.
- 了解结构缺陷如何影响水分裂的催化性能.
主要方法:
- 随机表面行走 (SSW) 路径采样方法,以调查固体相变机制.
- 评估不同MnOx结构和缺陷地点的OER活动的第一原则计算.
- 分析结构变化,包括溶解,脱位和层变化.
主要成果:
- 在高电压下形成的过渡性H0.5MnO2阶段中进行旋转到层的过渡.
- 这种过渡会产生各种有缺陷的MnOx结构,包括Mn空缺的结构.
- 一个特定的边缘站点与邻近的Mn空隙,具有"缺少一个角落的伪古巴"结构,具有较高的OER活动,超电位为0.59V.
结论:
- MnOx催化剂的高OER活性源于缺陷的位点,特别是那些具有Mn空位的位点,这些位点增强了中间吸附.
- 已发现的活性位点结构与自然光系统II (PSII) 中的催化中心有相似之处.
- 这项研究提供了有关MnOx催化剂设计的原子层次见解,以实现高效的人工水分.
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