近邻环境对过渡金属单原子电催化析氢性能的调控机制研究

Transition metal single atoms possess high atom utilization and active centers with unsaturated coordination, whose catalytic activity is closely related to the surrounding environment. However, the effect mechanism of surrounding environment on the electrocatalytic hydrogen evolution reaction upon single atoms is still not clear, which significantly limits their application. In this project, 3D porous carbon fiber supported transition metal Ni/Fe single atoms will be constructed with different coordination environment. The local atomic structure and coordination of single atoms on carrier would be examined by spherical aberration correction TEM and synchrotron radiation technology. And then the effect of surrounding environment (coordination environment and adjacent single atom sites) on the differential charge density, adsorption energy and free energy evolution of transition metal single atoms will be investigated by density functional theory calculation. The coupling mechanism of coordination environment to single atoms, as well as the effect of neighbor cooperative catalysis on the catalytic performance, will be studied, aiming to reveal the regulated mechanism of surrounding environment on the electrocatalytic performance of single atoms. Based on the above work, the correlation of single atoms and their surrounding environment will be explored for developing highly active and low-cost electrocatalysts.

过渡金属单原子具有高的原子利用率和不饱和配位的活性中心，其位点催化活性与近邻环境密切相关，但目前近邻环境对单原子电催化析氢性能调控机制的研究相对薄弱，这严重制约了单原子催化剂在电催化领域的应用。针对该问题，本项目拟以Ni、Fe过渡金属单原子为研究对象，首先，利用三维多孔碳纤维构造不同的配位环境以限域过渡金属单原子，通过球差电镜和同步辐射技术从原子尺度解析单原子的局部原子结构及配位情况。然后通过密度泛函理论建立模型研究单原子周围的几何和电子结构，分析近邻环境（配位环境、邻近位点）对过渡金属单原子差分电荷密度、可能的活性位点上的吸附能以及自由能演变的影响，阐明配位环境对过渡金属单原子的耦合机制，揭示近邻协同催化对单原子催化的影响规律，进而建立近邻环境对单原子电催化析氢性能的调控机制。通过以上目标的实现，建立单原子催化剂与近邻环境的内在联系，为开发高效经济电催化剂提供理论支持。

由于碳达峰、碳中和目标的提出以及氢能产业的飞速发展，绿氢（利用可再生能源制氢）在降碳中发挥的作用备受关注。电解水制氢是一种获取氢气的绿色途径，然而迫切需要开发高效稳定且价格低廉的电解水催化剂，进而推动碱性电解水制氢产业发展。单原子催化剂近100%的原子利用率和丰富的配位环境使其在催化领域有着广泛的应用前景。本项目提出以三维多孔碳纤维作为载体，利用其丰富的孔道结构实现过渡金属单原子的高效负载和活性位点的充分暴露。通过调控单原子的配位环境实现了对其几何结构和电子结构的可控调节，进而优化其电催化析氢性能，揭示了近邻环境对单原子结构和性能的影响机制，建立了单原子催化剂结构和性能的构效关系。同时，制备了多种具有双阴离子的过渡金属化合物催化剂，阐明了双阴离子效应对材料电催化性能的作用机制。本项目研究内容为电催化制氢产业的发展提供了一定的理论基础，为开发高效经济电催化剂提供借鉴。