SnO2@Pd纳米核壳催化剂的构筑及其对乙醇氧化反应协同催化机理研究

The sluggish kinetics, poor stability and confused mechanism of the catalysts for ethanol electrooxidation reaction (EOR) hinder the development for the direct ethanol fuel cells (DEFCs). To solve the above-mentioned problems, a novel SnO2@Pd catalyst with nano core-shell structure is proposed, and it probably exhibits high catalytic activity and stability for the EOR, and therefore it is promising to tackle the activity and stability problems of DEFCs. In this research, the critical parameters and the formation mechanism of the synthesis will be researched to control constitute, structure, and morphology of the SnO2@Pd catalyst. The relationship between constitute, structure, morphology and performance of the SnO2@Pd will be established. Furthermore, we propose a carbon-coated-isolation method to block the formation and release passageways of oxygen-containing species on the surface of SnO2, and illuminate the synergistic effect between SnO2 and Pd in SnO2@Pd catalyst. In additional, with the help of XPS and computational chemistry methods, the synergistic effect and EOR mechanism will further be elaborated. According to the obtained synergistic effect theory, the SnO2@Pd catalyst will be further modified and the SnO2@Pd catalyst with higher activity and stability will be achieved. Not only is this work beneficial to broaden and enrich the electrocatalytic theories, but also is favorable for constructing high catalytic activity and high stability catalysts for EOR.

乙醇氧化催化剂活性低、稳定性差、催化机理不明确等问题是困扰直接乙醇燃料电池商用化发展的最大障碍。针对上述问题，本项目设计并构筑具有高活性和高稳定性的SnO2@Pd纳米核壳结构催化剂，系统研究关键制备参数对催化剂组成、结构、形貌的影响及其机制，揭示组成、结构、形貌等因素与SnO2@Pd催化活性和稳定性之间影响规律；在此基础上，利用碳包覆层切断含氧基团在SnO2表面的形成和释放通道，对比研究碳包覆前后SnO2@Pd催化剂差异，揭示SnO2@Pd催化剂中SnO2与Pd之间协同效应的本质；结合XPS、理论计算化学等手段进一步阐明协同效应和催化机理；最后，对最佳条件下制备的SnO2@Pd催化剂进行修饰，增强SnO2@Pd的协同效应，最终获得具有高活性和高稳定性的直接乙醇燃料电池阳极催化剂。本项目的实施有助于丰富和完善燃料电池电催化理论基础，为构筑高性能乙醇氧化催化剂提供理论依据和技术指导。

直接乙醇燃料电池是一种绿色环保的清洁能源技术，然而由于直接乙醇燃料电池阳极催化剂存在催化活性低、稳定性差和反应机理仍不明确等问题，严重的阻碍了其商用化的进程。针对以上问题，本项目提出利用碳包覆手段限制活性氧的协同效应研究新策略，阐明了钯基氧化物复合催化剂在直接醇类燃料电池中钯-氧化物之间协同效应的本质机理。利用杂原子掺杂氧化物、碳载体结构设计、氮掺杂等手段调控钯表面电子结构，增强钯-氧化物之间协同效应，提高钯-氧化物分散性，制备出一系列具有高催化活性和稳定性的钯基阳极催化剂。在此基础上，利用高性能钯-氧化物复合催化剂为阳极，非贵金属催化剂为阴极，发展以全透过型纤维膜基的高性能直接醇类燃料电池组装策略。本项目的顺利实施为下一代高性能直接醇类燃料电池阳极贵金属-氧化物复合催化剂的设计提供了理论指导，并为低成本燃料电池结构的设计提供了新的技术思路。