核壳结构金属@金属氧化物阵列电极的设计、构筑及其增强析氧催化活性

Design and construction of stable, highly-active and low-cost oxygen evolution reaction (OER) electrodes are highly important for the enhancement of energy conversion efficiency and pushing forward the industrial application of water electrolyte. Realizing synchronously the high-performance and long-term stability of OER electrode is challenge in present state, and development of new-type electrode structure is one of the important strategy to settle down this problem. In this project, we firstly prepare core-shell structured metal@metal-oxide electrode with one-dimensional array structure. By changing the types and ratios of metal species in the electrode, the amount of metal active sites and electronic structure of metal-site in the electrode were improved. Furthermore, by utilizing the one-dimensional nano-cone array, we tried to investigate the influence of charge density on the different part of nano-cone on OH- concentration in the electrical double layer between electrode and electrolyte. By performing this project, we tried to systematically investigate the influence mechanism of multi-scaled structure, charge transfer rate and the composition of metal active sites in the electrode on the difference of electronic structure of active sites, amounts of active sites, as well as the concentration of OH- in the electrical double layer. It is highly important to provide the theoretical basis and technical strategy for constructing the efficient and stable OER electrode by systematically studying the influence of compositions, structure and charge density distribution of electrode on their catalytic activity.

稳定、高效、且廉价的析氧催化电极的设计、构筑对于提高水电解池能量转换效率，推动器件规模化应用具有重要意义。实现析氧催化电极高活性和长程稳定性的兼容是目前的关键问题。而引入新型电极结构是解决上述问题的重要手段。本项目首先构筑核壳结构金属@金属氧化物一维纳米棒阵列电极，通过调控电极材料组分和结构，提高电极的金属活性位点数量和优化金属位点的电子结构；在此基础上，通过引入锥形结构，构筑具有表面电荷密度梯度分布特征的一维纳米锥形结构阵列电极，着重研究纳米锥（锥尖和底部）表面电荷密度的梯度分布对界面双电层中OH-浓度的调控作用，揭示电极的金属活性位点组成、结构、电荷传输速率对其催化活性位点数量和电子结构、以及双电层中OH-浓度的调控作用和根本机制；本项目通过系统电极的组分、结构及电荷密度分布对其催化活性的影响，为发展高效稳定的析氧电极提供理论依据和技术路线。

构筑高活性和稳定性的析氧催化电极，对推动电解水池和电化学二氧化碳还原的规模化应用至关重要。本基金项目主要针对催化电极设计过程中活性位点数量较低、电化学析氧反应过程中稳定性较低的问题，通过一维阵列电极的构筑和金属@金属氧化物核壳结构的引入，实现活性位点数量的提高和金属电子结构的优化，从而增强电极析氧活性。（1）探究纳米锥阵列电极核壳结构材料元素种类以及其在析氧催化反应中的变化，对析氧反应活性和稳定性的影响；（2）考察核壳结构金属磷化物纳米线和纳米片电极在析氧反应（OER）和析氢反应（HER）过程中的结构演变过程，并通过构筑二元异质结构金属磷化物催化电极，探究其抑制催化电极表面结构动态演变对析氧反应活性和稳定性的影响；（3）考察核壳结构自支撑电极活性位点数量和导电性对其析氧反应催化活性和稳定性的影响。本项目的实施为推动高效、快速且稳定的氧气析出过程、提高水电解池的能量转换效率和长循环稳定性提供了理论基础和技术支撑。