混合价态钒氧化物基复合材料热力学研究及电催化应用

我国钒资源利用新工艺中，涉及混合价态钒氧化物中间产物，而混合价态钒氧化物用在电催化方面研究较少，但却发现能在水溶液中催化析氢和析氧两个极端反应。现有钒氧化物热力学数据不完善、有些则存疑，钒氧化物的Pourbaix图也不全。因此，研究者无法掌握混合价态钒氧化物中间产物的物相价态转变过程的规律，无法确定各个物相的电位稳定区，钒的氧化还原与可浸出性及在电化学应用存在不可预测性。本研究拟利用热力学原理对现有数据评估，并采用精密气氛控制的快速升温-淬火的热天平装置进行实验验证，依此绘制V-O体系相稳定区图和完善的Pourbaix图，进而分别研究含有C、Fe、Si的三元体系的热力学问题。在此基础上，设计并制备具有高活性和稳定性的电催化材料。通过测试来揭示电催化材料各个组分之间的相互作用关系及对催化性能的影响。项目研究结果能为钒资源提炼新工艺和钒相关产品的高值化及设计制备钒电催化材料提供理论指导。

In the new process of vanadium resource utilization in China, the intermediate products of mixed valence vanadium oxides are involved, and the mixed valence vanadium oxides are a few studied in electro-catalysis, but it is found that they can catalyze two extreme reactions of hydrogen and oxygen evolution in aqueous solution. The present thermodynamic data of vanadium oxides are not perfect, some are doubtful, and the Pourbaix diagram of vanadium oxides is not complete. Therefore, it is difficult to discover the law of phase transformation of mixed valence vanadium oxide intermediates, to determine the potential stability zone of each phase, and to predict the properties/abilities of redox and leaching of vanadium and their electrochemical applications. This study intends to use the thermodynamic principle to evaluate the existing data, and adopt the rapid temperature raising-quenching thermal balance equipment with atmospheric control to carry out the experimental verification, according to which the phase stability diagram (Predominance area diagram) of V-O system and the Pourbaix diagram are drawn, and then the thermodynamic problems of ternary system with C, Fe and Si are studied respectively. On this basis, electrocatalytic materials with high activity and stability are designed and prepared. The interaction between the components of the electrocatalytic material and its influence on the catalytic performance are revealed by testing. The results of these investigations can provide theoretical guidance for a new process of vanadium resource extraction and a high value of vanadium related products as well as the design and preparation of vanadium electrocatalytic materials.