多酸簇限域转化法合成磷化钼基团簇用于高效的电催化析氢

In this project, we want to design the molybdenum phosphide-based clusters for efficient electrocatalytic hydrogen evolution （HER）by the combination of the noble metal-like electronic structure characteristics of the molybdenum phosphide and the advantages of the clusters. Taking the advantages of molybdenum-oxide polyoxometalates (POMs), such as variable structure and high negative charge, we propose to prepare the molybdenum phosphide-based clusters with same size as POMs clusters through protecting POMs by the small nitrogen-containing molecules (imidazole etc.), and thus inhibiting the aggregation and growth of clusters in the phosphating process. The size (atomic numbers of Mo), the Mo/P ratio of molybdenum phosphide-based clusters and doping will be controlled by adjusting the structure of POMs clusters, the ligand types and the parameters of phosphating process. The composition, size and coordination environment for molybdenum phosphide-based clusters will be confirmed by combining a series of methods, such as transmission electron microscopy, synchrotron radiation X-ray absorption spectroscopy and mass spectrum etc. Based the results, the general rule for the controllable syntheisis of molybdenum phosphide will be established. Further, the activity and stability of molybdenum phosphide for HER will evaluated by the combination of the different electrochemical methods. The effects of size，components on the electrocatalytic performance will be analyzed by combining the results of the structural characterization, theoretical calculation and electrochemical tests. The study will provide an effective method for designing molybdenum phosphide-based clusters with controllable size and components, also provide the theoretical and experimental basis for the molybdenum phosphide-based clusters with the high catalytic activity and stability.

本项申请拟结合磷化钼具有类贵金属的电子结构等特征以及团簇的优势，设计合成磷化钼基的团簇用于高效的电催化析氢。基于钼氧基多酸簇结构多变和高的负电荷等特点，拟通过咪唑等含氮小分子与钼氧基多酸簇配位实现对多酸簇的保护，从而抑制加热磷化过程中团簇的聚集和长大，获得与多酸簇尺寸相当的磷化钼基团簇。通过调变多酸簇结构、配体种类并控制磷化过程参数等实现对磷化钼基团簇尺寸（钼原子数）、钼/磷比及掺杂等的控制。利用透射电子显微镜、同步辐射X射线吸收谱、质谱等方法给出磷化钼基团簇的尺寸、组成、配位环境等信息，总结磷化钼基团簇控制合成的一般规律。综合多种电化学手段评价磷化钼基团簇电催化析氢反应的活性和稳定性；与结构表征、理论计算等结果相结合分析团簇尺寸、组成等对电催化性能的影响规律。本项申请将为设计尺寸、组成可控的磷化钼基团簇提供有效的方法，并为其在电催化中的应用提供一些理论和实验依据。

过渡金属间隙化合物具有类贵金属的电子结构以及高的稳定性等特点，是有前景的电催化分解水制氢材料。本项申请拟结合钼基间隙化合物的特征以及团簇的优势，设计合成小尺寸乃至团簇结构的钼基间隙化合物用于高效的电催化析氢。利用多酸簇结构稳定、尺寸小等特征，通过咪唑等含氮小分子与钼氧基多酸簇配位实现对多酸簇的保护，抑制热处理过程中颗粒的聚集和长大，最终获得小尺寸的钼基间隙化合物。利用聚乙二醇调节磷钼酸簇和三聚氰胺组装，构建二维磷钼酸-三聚氰胺无机-有机杂化材料，经可控热解构建二维多孔磷化钼-氮化钼异质结电催化材料，可用于宽pH电解液中有效制氢。同时，发现以生物质蛋白为配体，与磷钼酸簇组装可获得片层结构前驱体，热解后获得由磷化钼颗粒组装而成的片层催化材料，在中性体系中展示出好的电催化析氢性能。以多酸簇为母体，与含有二甲基咪唑的ZIF-67组装获得结构可控的前驱体，控制两者的组装条件，可获得实心结构、中空结构的钼基前驱体，经控制热解条件获得相应结构的钼基间隙化合物，作为电催化析氢和析氧材料，展示了优异的性能。利用透射电子显微镜、XPS等方法确认材料的结构信息，给出控制合成的一般规律。综合多种电化学手段评价材料的电催化析氢反应的活性和稳定性；与结构表征、理论计算等结果相结合分析催化剂尺寸、组成等对电催化性能的影响规律。本项申请为利用多酸簇为母体，设计合成小尺寸的钼基间隙化合物提供有效的方法，为获得高效的电催化分解水制氢等催化材料一些理论和实验方面的依据。