氧空位多元钙钛矿纳米纤维的设计与调控及其电解水制氢性能研究

Designing efficient and stable catalysts for electrocatalytic water splitting is the core technology and key bottleneck for clean and efficient energy systems. In this study, we used the electrospinning and high-temperature post-treatment to prepare multi-element perovskite oxide nanofibers with abundant oxygen vacancies, serving as cathode and anode for bifunctional electrocatalytic hydrogen production. Carbon nanofibers were used as reaction vessels and loading carriers, and the perovskite nanofibers with oxygen vacancies and different structures were prepared by multiple transition metal doping and high temperature thermal reduction. The influence of the chemical composition of transition metal, the morphology and content of carbon nanofibers, and the post-treatment conditions on the key parameters of oxygen vacancy structure and density, crystal type and other key parameters were investigated, and the oxygen vacancy structure can be controlled. By regulating the content of carbon nanofibers, the nanostructuring of perovskite oxides can be achieved. This study will solve the problems of high energy barriers for the formation of oxygen vacancies, low intrinsic activity of perovskites, and amorphization of the perovskites surface, and further improve the repeatability and stability of electrode materials. This study explores and reveals the difference in energy band structure caused by oxygen vacancy structure, the strong interaction between electrons, and the reaction mechanism of electrodes in different electrolytes, providing new methods and ideas for non-precious metal electrocatalytic materials.

设计高效稳定电解水催化材料是清洁能源系统的核心技术和关键瓶颈。本研究利用静电纺丝和高温后处理等方法制备具有丰富氧空位结构的多元钙钛矿氧化物纳米纤维，实现阴阳极双功能电催化制氢。以碳纳米纤维为反应容器和负载载体，采用多元过渡金属掺杂和高温热还原的方法制备不同结构的氧空位钙钛矿纳米纤维。研究过渡金属化学组成、碳纳米纤维形貌和含量、高温后处理工艺条件对氧空位钙钛矿结构的微观形貌、氧空位密度、晶型种类等关键参数的影响，掌握氧空位结构的调控方法和形成过程。通过调控碳纳米纤维含量实现钙钛矿氧化物纳米结构化，解决传统方法构建氧空位能量势垒过高、钙钛矿固有活性低，表面非晶化等难题，提升电极材料的重复性和稳定性。探索并揭示氧空位结构引起的能带结构差异、电子间的强相互作用、电极在不同电解液中的反应机理，为非贵金属电催化材料提供新的方法和思路。

提出了基于静电纺丝法构建多元钙钛矿氧化物中空纳米纤维的可控合成方法，设计和制备 LaCoO3、La0.6Sr0.4CoO3、La0.6Sr0.4Co0.8Fe0.2O3、 La0.7Sr0.3Co0.25Mn0.75O3、双相La2NiO4和La0.9Sr0.1NiO3等氧空位中空纳米纤维，探索其在碱性和中性条件下的 HER 和 OER 性能，通过纳米纤维限域效应调控中空纳米纤维的孔隙结构，掌握具有高催化活性氧空位中空纳米纤维结构的制备工艺和条件。系统研究了A位和B位金属掺杂对钙钛矿纳米纤维电解水性能的影响，揭示了钙钛矿A位和B位元素调控对氧空位缺陷的影响因素，探索钙钛矿中空纳米纤维结构调控与电解水催化性能之间的关系。利用纳米纤维限域合成效应，提出了二元过渡金属硫化物界面工程设计策略，构筑了多种核壳结构，揭示了纳米异质界面对催化性能的协同增强效应。发展了石墨层限域原位合成金属间化合物的方法，揭示了金属间化合物电子结构与电解水性能之间的对应关系，揭示了不同物相之间纳米界面在电子和中间体等表面物质的吸附、转化和运输中的关键作用，发展了利用低电负性取代工程设计具有增强电子转移的电催化剂的方法。