原位小角中子散射方法研究新型过渡金属碳化物纳米结构在石墨烯表面的生长机理

Transition metal carbides (TMCs, such as VC, WC/W2C, MoC/Mo2C and TaC) have attracted considerable attentions due to their great potential application as non-precious metal catalysts. In the previous reports, the proposers have confirmed the feasible synthesis of novel TMCs nanoarchitectures with uniform and well-defined shape on graphene surface. In this proposal, the proposers design a novel in-situ small angle neutron scattering (in-situ SANS) experiment to investigate the growth mechanism of the novel TMCs nanoarchitectures on graphene through the in-situ observation of the structure and morphology evolution during the annealing treatment. X-ray photoelectron spectroscopy (XPS) and X-ray absorption fine structure (XAFS) will be applied to study the electronic structure and chemical coordination environment of novel TMCs nanoarchitectures. Charge density difference and calculated average adsorption energy of novel TMCs nanoarchitectures on graphene nanocompositions will be obtained by density functional theory (DFT) calculations. Hence, based on the experimental and theoretical analysis, the growth mechanism of the novel TMCs nanoarchitectures on graphene will be proposed. The catalytic performance of novel TMCs nanoarchitectures on graphene nanocompositions will be investigated as non-precious metal catalysts toward hydrogen evolution reaction (HER) in water splitting and oxygen reduction reaction (ORR) in proton exchange membrane fuel cells (PEMFCs). The accomplishment of this project will develop a novel in-situ SANS methodology to study the growth mechanism of novel nanoarchitectures, pave the way for the applications of TMCs in water splitting and PEMFCs, and offer a new idea to design and optimize performance-oriented novel nanoarchitectures.

过渡金属碳化物（TMCs）是一种重要的非贵金属催化剂。申请人前期研究发现可在石墨烯表面实现新型TMCs纳米结构的生长。在此基础上，本项目设计原位小角中子散射（in-situ SANS）实验，旨在实现新型TMCs纳米结构在生长过程中结构演化的动态观测和研究。运用X射线光电子能谱(XPS)和X射线吸收精细结构谱（XAFS）研究材料的电子结构和化学配位环境，通过计算TMCs和石墨烯之间的差分电荷密度以及平均吸附能，从而获得TMCs和石墨烯之间的相互作用。通过上述实验和理论结合的方法来揭示新型TMCs纳米结构在石墨烯表面的生长机理。研究它们的催化活性，推动其作为非贵金属催化剂在电解水制氢和燃料电池中的应用。本项目的完成将发展一种基于SANS的研究纳米材料生长机理的技术方法，还将为基于新型TMCs纳米结构催化剂的设计和生长提供新思路。

由于具有良好的导电性、稳定性、独特的电子结构以及“类铂”的催化性能，过渡金属碳化物（TMCs）作为非贵金属催化剂在很多催化反应中具有替代贵金属铂的潜力。本项目构建纳米结构的TMCs不但可以调控TMCs本身的电子结构，还可以改善催化反应过程中的反应物介质扩散和传导。本项目设计原位小角中子散射（in-situ SANS）实验，金属盐前驱体吸附在氧化石墨烯表面，在高温处理过程中，观察TMCs生长过程中的纳米结构的变化。运用X射线光电子能谱(XPS)和X射线吸收精细结构谱（XAFS）研究材料的电子结构和化学配位环境，通过计算TMCs和石墨烯之间的差分电荷密度以及平均吸附能，从而获得TMCs和石墨烯之间的相互作用。通过上述实验和理论结合的方法来揭示新型TMCs纳米结构在石墨烯表面的生长机理。研究它们的催化活性，推动其作为非贵金属催化剂在电解水制氢和燃料电池中的应用。