非贵双金属纳米结构材料作为高效的氢气氧化和析出催化剂

Fuel cells which convert the chemical energy of hydrogen to electricity, and electrochemical water splitting which produces CO2-free hydrogen, are considered as two of the most important technologies for the realization of “hydrogen economy”. However, the large-scale application of these two technologies are currently limited due to their heavy reliance on Pt and other precious metals as electrocatalysts. To reduce the high cost, much research efforts were devoted on switching their operation conditions from acid to base so that many non-precious element candidates could be favored by thermodynamics. As to the cathode side of fuel cells where oxygen reduction occurs and the anode side of electrochemical water splitting where oxygen evolution occurs, breakthrough non-precious electrocatalysts were successfully developed in the past decade. However, electrocatalysts for the anode side of fuel cell where hydrogen oxidation occurs and the cathode side of electrochemical water splitting where its reverse reaction, hydrogen evolution occurs were still in lack of significant improvement. The main goal of present proposal is to develop non-precious bimetallic catalysts for HOR/HER in alkaline condition with activity close to that of Pt. The key to success is to create a beneficial synergy effect between two types of metal atoms achieving an optimal surface electronic structure for HOR/HER. Highly active bimetallic surface will be identified from a combination/interplay of theoretical calculation and experimental modelling study, based on which high-performance catalysts with advanced nanostructures will be designed and characterized for practical application. The proposed research is also believed to provide new design principles of bimetallic catalysts for other important reactions such as CO2 reduction and biomass conversion.

作为氢能源转化的燃料电池和氢能源绿色制备的电解水工艺是实现未来“氢经济”两个重要技术手段。而这两项技术对与Pt金属作为催化剂的大量需求则是制约它们被大规模应用的最重要原因之一。为了使用非贵材料代替Pt以及其他贵金属催化剂，近年来有大量的学术研究尝试将这两项技术从酸性环境转换到碱性环境以获得热力学上的稳定性，并且已在燃料电池的正极氧还原和电解水制氢的负极氧析出催化上获得了突破性的进展。然而遗憾的是，在使用非贵材料催化碱性环境下燃料电池的负极氢气氧化和电解水制氢正极氢气析出这一对互逆反应仍然鲜有大的进展。针对现状况，本课题拟设计非贵双金属催化剂，利用原子间的有益协同效应调整表面电子结构并获得在碱性环境中与Pt相接近且稳定的催化性能。课题研究将采用理论计算和实验模型之间的动态交互作用构建并筛选双金属表面，通过纳米结构设计获得最终可实际应用的高性能催化材料，并为催化剂的产业化升级作研究准备。

对Pt金属催化剂的大量需求是制约氢能源转化的燃料电池和氢能源绿色制备的电解水这两项工艺被大规模应用的最重要原因之一。为了使用非Pt金属催化剂，近年来有大量的学术研究尝试将这两项技术从酸性环境转换到碱性环境以获得热力学上的稳定性，并且已在燃料电池的正极氧还原和电解水制氢的负极氧析出催化上获得了突破性的进展。本项目针对在使用非Pt金属材料催化碱性环境下燃料电池的负极氢气氧化和电解水制氢正极氢气析出这一对互逆反应仍然鲜有大的进展这一状况，设计并建立了考虑溶剂和电极电势的电化学计算模型，探究了金属及双金属表面氢气析出和氧化反应的机理，设计新型的反应方式、筛选了新型的双金属电催化表面，最后制备了纳米双金属催化材料，在实际反应中进行电催化性能的表征和评价。项目执行期间发表SCI论文7篇，培养博士研究生3名，硕士研究生1名。