铁电极化调控外延钙钛矿薄膜催化活性的研究

The developing of sustainable and clean energy, such as hydrogen energy by water splitting, has been playing a key role in solving energy crisis and environment pollution. With no doubt, high efficient oxygen evolution reaction (OER) catalysts take the priority in such technology. In this research, the polarization of ferroelectric domains in PbTiO3 will be introduced to improve the OER performance of SrCoO3-δ catalyst in electrochemical reactions by adopting a Laser-MBE prepared SrCoO3-δ/PbTiO3/SrRuO3/ SrTiO3 multilayers. On the one hand, the perovskite nature of the SrCoO3-δ catalyst could be stabilized as the oxygen vacancies produced during OER reactions are driven to the bottom layer by the polarization electric filed; on the other hand, the diffusion of oxygen vacancies could be accelerated by the polarization electric field as well. Thus, the overall catalysis performance would be improved. In this project, we firstly target on the preparation of epitaxial multilayers with high OER performance, and then try to figure out the relationship between the ferroelectric domains and the OER performance. To understand the mechanism of polarization enhanced electrochemical catalysis, the band structures of the SrCoO3-δ/PbTiO3 heterojunctions will be built with the aid of first principle calculations, which contributes to the improvement in catalysis performance and the design of novel transition metal oxide catalyst in further.

清洁可再生能源的开发，如电解水制氢是解决能源与环境问题的重要途径。其关键技术是开发高效的析氧反应催化剂。本项目拟以激光分子束外延法制备的多层膜SrCoO3-δ/PbTiO3/SrRuO3/ SrTiO3为对象，采用电化学的方法，研究PbTiO3铁电薄膜的极化对提升钙钛矿结构SrCoO3-δ薄膜催化速率的影响，以改进析氧反应催化剂的效率。在PbTiO3薄膜极化电场的作用下，一方面，SrCoO3-δ薄膜中的氧空位会不断向底层扩散，从而稳定了表面钙钛矿结构的催化效率；另一方面，极化电场提升了薄膜的空穴电导，从而提升了催化效率。本项目拟通过实验探索，设计制备出高效催化的外延多层膜；并结合理论计算，明确铁电调控层畴结构与催化性能的关系，揭示最大催化效率下催化层与铁电层的界面能带结构，深入理解铁电极化增强电化学催化性能的机制，为进一步研究控制和改善过渡金属氧化物的催化性能做出理论和应用的参考。

清洁可再生能源的开发，如电解水制氢是解决能源与环境问题的重要途径。其关键技术是开发高效的析氧反应催化剂。本项目以激光分子束外延法制备的多层膜SrCoO3-δ/PbTiO3/SrRuO3/ SrTiO3为对象，采用电化学的方法，研究PbTiO3铁电薄膜的极化对提升钙钛矿结构SrCoO3-δ薄膜催化速率的影响，以改进析氧反应催化剂的效率。本项目通过实验探索，首先制备了高质量SrCoO3-δ 单层外延薄膜，发现SrCoO3-δ单层薄膜的在电催化环境下的由钙铁石结构到钙钛矿结构的可逆转化。接着制备了高质量SrCoO3-δ/PbTiO3/SrRuO3外延多层膜。通过对SCO/PTO/SRO/NSTO多层薄膜的电催化研究，我们发现：电极化PTO铁电薄膜可以有效提升薄膜的催化效果。相对钙钛矿结构的SCO薄膜而言，铁电极化对钙铁石结构SCO的电催化性能提升明显。催化层SCO薄膜必须维持一定的厚度以保持结构的稳定性。这些发现为进一步研究控制和改善过渡金属氧化物的催化性能做出理论和应用的参考。

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