氢氧燃料电池氢阳极金属-金属化合物复合催化剂的理论设计与筛选

Developing a high active anode non-platinum catalyst for hydrogen oxidation reaction (HOR) has been one of the major challenges for the lowering cost and commercialization of proton exchange membrane fuel cells (PEMFCs). Recent research found that the adsorption of hydroxyl species (OH) benefits the catalysis of HOR. Based on the effect of OH on the activity of catalysts, and the HOR catalytic activity and CO tolerance of metal compounds, such as the carbides, nitrides, oxides, in this project, we computational design and screen metal–metal compounds hybrid catalysts for catalysis of HOR using the binding energy of H (HBE) and CO (CBE) on the catalysts surface as reactivity and CO tolerant descriptors respectively. Firstly, we construct the metal-metal compounds hybrid catalysts, and perform DFT calculation to study the interaction between the metal and metal compounds. Secondly, the relationship between the HBE (or CBE) and the electronic structures of hybrid catalysts are investigated to find the key properties of hybrid catalysts, and to explore the effect of hybrid catalysts on HBE and CBE. Finally, the results of above analysis are used to engineer the excellent active, CO tolerant and stable metal-metal compounds hybrid catalysts by changing its composition and structure.

开发高活性抗中毒的阳极氢氧化（HOR）非铂催化剂是降低燃料电池成本，推动其商业化的关键。根据OH物种提高催化剂HOR活性的机理，以及金属化合物本身固有的催化活性和CO抗中毒特性，我们提出“氢氧燃料电池氢阳极金属-金属化合物复合催化剂的理论设计与调控”。主要利用理论模拟与实验相结合，以氢与催化剂间的结合能（HBE）为HOR的活性指标，CO的结合能（CBE）为抗CO中毒指标，通过探究金属-金属化合物间相互作用对HBE、CBE的影响机理，寻找调控HBE和CBE的关键因素，为设计高活性、抗CO中毒和高稳定性的HOR催化剂提供理论依据。

项目围绕化合物-金属复合催化剂的理论设计与实验制备展开。针对氢氧化与析氢互为逆反应，本项目通过研究金属化合物-金属之间的相互作用，探究其结构的变化和中间物种对催化剂催化HOR/HER反应机理的影响，确定其催化机制，设计制备高活性和高稳定性的HOR/HER催化剂。从催化剂本身性质出发，结合ΔG(H*)，ΔG(H2O*)和ΔG(OH*)给出在不同电极电势下HOR机理的全面描述，明确了OH对HOR/HER机理的影响机制；通过计算并比较不同过渡金属低指数晶面上吸附H和OH的难易程度，设计并筛选出具有良好碱性HOR催化活性的MnCu, CoCu, NiCu近表面合金催化剂；发现金属-金属氧化物高效催化析氢反应的本质，在于金属与氧化物间的电子转移改变了金属与氧化物界面处的化学环境，使其界面区域成为难以吸附H2O和OH物种却有利于H物种的吸脱附的活性中心，并进一步结合实验发现界面位点数量及界面电荷转移与活性的强相关性；X/Ni(100)的电子结构、H结合能和HER活性，可通过改变X的电负性(χx)和主量子数(ηx)来有效地调节，并发现χx和ηx是评价和预测NiX催化剂催化活性的两个重要描述符；基于碱性条件下TM-V2CO2上HOR反应机理，设计并筛选出具有良好催化活性且成本较低的HOR催化剂（Sc-，Ti-，V-，Cr-，Mn-，Fe-和Zn-V2CO2）；根据计算结果，发展了“金属诱导晶化”和“自组装及预成形”等试验方法，通过调节可控变量，合成了稳定性好、且具特定形貌、催化性能优异的Ni-VC@C/Ti、Mo2C/C和AuPt合金等一系列复合催化剂。