碱性体系非贵金属三元合金H2氧化电催化剂研究

Alkaline polymer electrolyte fuel cells (APEFCs) have gained increasing attention in recent years due to their potential for resorting to non-precious electrocatalysts. However, the APEFCs using non-precious electrocatalysts at both anode and cathode sides are still rarely reported, which is mainly hindered by the lack of high-performance non-precious electrocatalysts for the anode hydrogen oxidation reaction (HOR). Ternary alloy catalysts have recently been shown to be compelling systems for improving the HOR performance. While the study of ternary alloy HOR catalysts remains scare due to the experimental difficulties involved in examining a wide composition range and the complexity of analyzing the contribution of each component. Here we propose a systematic study of ternary alloy HOR catalysts on planar model electrodes to establish the “composition – performance (including electrocatalytic activity and anti-oxidation property)” relationship. A series of ternary alloy planar model electrodes with various compositions are going to be high-throughput prepared by combinational magnetron co-sputtering deposition and then efficiently evaluated by home-designed HOR performance testing devices and processes. Density functional theory (DFT) calculations and molecular dynamics (MD) simulations will be applied to assess the adsorption energies of possible intermediates (Had and OHad) and the microscopic hydrophobicity of electrode surface, respectively. The HOR mechanism on ternary alloys, namely “electronic effect” and “synergistic effect”, can be clarified with combined experimental and computational studies. Moreover, the theoretical basis for enhancing the anti-oxidation property of ternary alloy catalysts will be explored through the analysis of band structure. Then the ternary alloy nanocatalyst with optimized composition will be controllably synthesized and applied to construct APEFCs without using any precious metal catalysts. This study is not only of fundamental scientific significance, but also of vital importance to the development and practical application of APEFCs with low cost and high performance.

碱性聚电解质燃料电池（APEFCs）有望使用全非贵金属催化剂，近年来备受关注。目前高性能阳极氢氧化反应（HOR）催化剂的缺乏严重阻碍了APEFCs的发展。已有研究表明非贵三元合金具有大幅提升HOR活性的潜力。但因其成分组合的多样性和体系的复杂性，这方面研究相当匮乏。本项目拟利用组合共磁控溅射批量制备三元合金平面模型电极，发展高效的HOR性能评估方法，系统研究三元合金的“组分-性能（活性和抗氧化性）”构效关系。结合密度泛函理论计算表面可能中间物种（Had和OHad）的吸附能，利用分子动力学模拟等研究表面微观亲疏水性，揭示三元合金表面“电子效应”和“协同效应”的影响。同时对能带结构进行分析，探究增强催化剂抗氧化性的理论基础。最后可控合成出优选组分的三元合金纳米粉体催化剂，并用于全非贵金属APEFCs的构建。本项目不仅具有基础科学意义，亦具有促进廉价高效APEFCs商品化的实用价值。

开发高效的阳极氢氧化反应（HOR）非贵金属催化剂是碱性膜燃料电池（APEFCs）发展亟需解决的瓶颈问题之一。当前碱性HOR非贵金属催化剂研究相对较少，缺乏明确的催化剂设计思路。本项目尝试了采用磁控共溅射方法批量制备不同组分的Ni基合金催化剂，并发展催化性能的快速测试评估方法，以实现碱性HOR催化剂的高效筛选、并明晰HOR催化剂的设计原则；同时尝试采用液相共还原、高温热解碳化等方法制备Ni基纳米粉体催化剂，进行非贵金属阳极APEFCs的装配测试。研究取得的重要结果包括：(1)建立起磁控共溅射批量制备多组分合金材料方法，能够拓展到其它研究体系中应用；(2)发现HOR和氢析出反应（HER）影响因素存在差异，有助于明晰碱性HOR机理、并指导高效HOR催化剂的设计；(3)利用热处理气氛调控碳包覆Ni核催化剂的表面状态，大幅提升HOR催化性能，实现了非贵金属阳极APEFCs性能和稳定性的突破；(4)拓展了锂-芳香化合物超强还原剂在负载型催化剂制备和化学预锂化两方面的应用。