MOF衍生碳负载Pt单原子催化剂的原子层沉积制备及其电化学稳定性研究

As the smallest unit of catalysis, the single atoms (SAs) catalysts possess excellent catalytic activity and maximum (100%) atom utilization efficiency, obtaining increasing attentions in the field of electrocatalysis. However, the low SAs loading (~0.1wt%) and poor stability are the major challenges that prohibit SAs application in the electrocatalysis. In this project, the atomic layer deposition (ALD) technique is proposed to synthesize the Pt SAs catalyst. To achieve the high Pt SAs loading, the metal-organic framework (MOF)-derived nanocarbon with high surface area and abundant nitrogen-doping sites is selected as the support for Pt SAs. Combining the support features of MOF-carbon with the self-saturating nature of ALD, the precisely controlled synthesis mechanism of Pt SAs will be investigated in this work; on the other hand, by atomic scale controlling the Pt SA-support interaction, the relationship between Pt SA-support interaction and the Pt SA stability will be studied. Applying the X-ray synchrotron radiation and density functional theory calculations, the stable mechanism of Pt SA via adjusting the Pt SA-support interaction will be revealed. This work could provide the theory guidance and technique support in the future design of single atom catalysts and favor their application in the fuel cells cathode to boost the oxygen reduction reaction.

作为催化的最小单元，单原子催化剂具有优异的催化活性和100%原子利用率，在电催化领域受到越来越高的重视。然而金属催化剂中单原子负载量低（~0.1wt%）、稳定性差等问题限制了单原子在电催化领域的规模化应用。为解决上述问题，本项目拟采用原子层沉积技术（ALD）精确可控构筑高负载量的Pt单原子催化剂。通过选用高比表面、富含氮掺杂位点的金属有机骨架（MOF）衍生碳作为载体，结合ALD自饱和限制的沉积特性，研究高负载量的Pt单原子催化剂在载体表面的可控合成原理；另一方面，通过原子尺度上调控Pt单原子与MOF衍生碳载体的相互作用，探索Pt单原子-载体相互作用与Pt单原子催化剂稳定性之间的关系。结合同步辐射和密度泛函理论计算（DFT）揭示Pt单原子-载体相互作用对Pt单原子的稳定机理。为设计高效稳定的Pt单原子催化剂，实现其在燃料电池阴极氧还原上的应用提供理论指导和技术支持。

本项目总体研究思路以制备高负载量、高稳定性的Pt单原子催化剂为目标，项目前期首先综述了MOF衍生的单原子催化剂在电化学应用领域的研究进展，然后通过调控Pt催化剂的尺寸效应和电子配位结构，成功合成了Pt单原子，亚纳米团簇和纳米颗粒等催化剂，电催化性能测试研究发现当Pt颗粒尺寸降低到单原子级别可以实现Pt催化剂较高的质量活性，以及低Pt催化剂在燃料电池催化层中的有效应用。项目研究中，考虑到氢能作为21世纪最具潜力的清洁能源，也是燃料电池比较重要的燃料，而电解水技术作为制氢的重要手段，其非贵金属基催化剂的设计研究将进一步推动电解水技术的商业化应用，故本项目研究拓展至单原子催化剂和非Pt催化剂用于电解水制氢技术以及电解海水制氢领域。