过渡族金属硫族化物/氮掺杂石墨碳异质结构的原位构筑及电催化析氢性能研究

The design and fabrication of a highly efficient and cost-effective electrocatalyst for hydrogen evolution reaction (HER) is crucial for clean energy technologies. The proposed project aims to develop a highly active and robust hybrid composite catalyst for HER that is constructed by transition metal chalcogenides (MX2, M = Fe, Co, or Ni and X = S or Se) nanoparticles embedded within porous nitrogen-doped graphitic carbon (N-GC) through the simultaneous pyrolysis and sulfidation or selenization of a preformed metal-organic framework (MOF) precursor. Through changing the experimental conditions, the effects of sulfidation/selenization temperature, reaction time and MOF: S/Se molar ratio on the phase compositions, N-doping and GC contents were thoroughly investigated. The relationship between the electrocatalytic performance and the morphology, microstructure, phase composition and surface property will be built by a series of electrocatalytic studies (e.g. onset overpotential, exchange current density, Tafel plot, turnover frequency and operation stability at all PH values). The electronic structures of MX2/N-GC hybrids and the free energy for atomic hydrogen adsorption on their surfaces will be studied using density function theory as well as their HER mechanisms being revealed. The experimental and computational modeling results will be used for the further optimization of the surface, phase and microstructure of the hybrid catalyst, achieving high catalytic performance with both excellent activity and stability, which even approaches to the commercial Pt/C catalyst.

设计和制备高效且价格低廉的析氢反应（HER）电催化剂对于发展清洁能源技术至关重要。本项目将利用金属有机框架作为前驱体，通过同步进行的热解及硫化/硒化过程，原位构筑一系列高效稳定的过渡族金属硫族化合物/氮掺杂石墨碳（MX2/N-GC，M=Fe, Co, Ni，X=S，Se）异质复合材料HER电催化剂。通过改变反应温度、时间以及反应物的配比等实验条件，结合热力学计算，研究这些因素对MX2型化合物的相组成、N掺杂及GC含量的影响规律。通过比较过电位、交换电流密度、塔菲尔斜率、反转频率及在酸碱条件下的操作稳定性等，揭示MX2/N-GC电催化HER性能与其形貌、微观结构、相成分、表面性质间的相互关系。分析MX2/N-GC的电子结构及计算氢原子在催化剂表面的吸附自由能变化，阐明HER催化机理。在此基础上，优化和设计MX2/N-GC的形貌和微观结构，以期制备出可与商业铂/碳催化剂相媲美的HER电催化剂。

设计和制备性能优异的非贵金属基析氢反应电催化剂对于氢能的应用具有重要意义。本项目利用金属有机骨架作为前驱体，通过热解及硫化/硒化/磷化/氮化等过程，原位构筑了一系列过渡金属基化合物/氮掺杂多孔石墨碳异质复合材料，考察了热解温度、反应物前驱体比例、反应气氛、反应时间等对复合材料的形貌、结构、组成等影响规律，结合电化学表征结果和第一性原理计算，系统地研究了复合材料与析氢催化性能的构效关系，制备出了一系列可与商业贵金属Pt/C相媲美的析氢反应电催化剂。通过设计石墨烯包裹的核壳沸石咪唑酯骨架，高温裂解制备了钴纳米粒子/碳管/石墨烯复合体系，实现了对氢吸附能的优化调控和活性位点的高暴露。利用钴基普鲁士蓝作为模板，通过控制硫化和碳化温度，实现了碳载体与与硫化钴电子耦合作用的调控；通过阳离子掺杂调控双碳耦合的二硒化钴使其从热力学稳定相到亚稳相，提升其电子传导能力。通过控制磷化条件和后续的硫化处理，利用多种杂原子掺杂增强双碳耦合磷化钴复合材料的界面电荷的转移能力。本项目在利用金属有机骨架构筑过渡金属基析氢反应电催化材料方面取得了一系列创新性研究成果。在此基础上，还探索了金属有机骨架衍生的金属硫族化合物/碳复合材料在储锂/钠以及电催化全水分解方面的应用。