单/双金属超薄涂层协同催化ZrCo合金吸/放氢过程及相关机制研究

The storage and supply of hydrogen isotope is critical for the development of thermonuclear fusion reaction. ZrCo alloy is considered to be a promising candidate to replace U for suitable physical and chemical properties. However, the activation property, the slower recovery/delivery rate and the poison resistance property of ZrCo alloy have limited its further application. Our preliminary work confirmed that the surface coating of ZrCo alloy with catalytic activities such as Pd and Ni coating could effectively improve the hydrogen absorption/desorption rate of the alloy. However, single metal coating has limitations to improve the comprehensive hydrogen storage properties of alloys and coating thickness obtained by conventional coating means is too thick and uneven. In this project, composite metal coating is constructed on the surface of ZrCo alloy by means of combination of electroless plating and replacement plating to improve the comprehensive hydrogen storage performance of ZrCo alloy. For further study, atomic layer deposition technology is adopted to realize controllable preparation of single/bimetallic ultrathin coating on the surface of the alloy, constructing high-dimensional catalytic activity sites. The relationship between the surface structure and the hydriding/dehydriding characteristics is established. By combining advanced characterization methods and theoretical calculation, the synergic catalytic effect mechanism of the monometallic/bimetallic ultrathin coating is exposed. The implementation of this project is of great importance to the surface modification of the hydrogen storage material system. Moreover, it is of practical value to realize the rapid supply of hydrogen isotope.

氢同位素快速储存与供给是保证热核聚变反应顺利进行的关键问题。ZrCo合金因合适的物理化学特性被认为是替代U较为理想的储氚载体。而ZrCo合金活化性能欠佳、吸氢动力学较慢、表面易中毒，限制其进一步应用。前期证实ZrCo合金包覆Pd、Ni涂层能有效改善合金吸放氢动力学，然而单一金属涂层对改善合金综合储氢特性具有局限性，而且常规包覆手段获得的涂层厚度过厚且不均匀。本项目以ZrCo合金为研究对象，采用化学镀+置换镀相结合手段，在ZrCo合金表面构筑复合金属涂层，提高ZrCo合金综合储氢性能。进一步优化工艺，采用原子层沉积技术，在合金表面实现单/双金属超薄涂层可控制备，构筑高维度催化活性位点，建立表面结构与吸放氢特性构效关系。结合先进表征手段及理论计算，揭示单/双金属超薄涂层协同催化合金吸放氢过程相关机制。本项目实施对储氢合金体系表面修饰有重要指导意义，对实现氢同位素快速供给技术具有实际应用价值。

氢同位素快速储存与供给是保证热核聚变反应顺利进行的关键问题。ZrCo合金因合适的物理化学特性被认为是替代U较为理想的储氚载体。而ZrCo合金活化性能欠佳、吸氢动力学较慢、表面易中毒，限制其进一步应用。本项目以ZrCo合金为研究对象，采用化学镀+置换镀相结合手段，在ZrCo合金表面构筑Pd/Ni复合金属涂层，提高ZrCo合金吸放氢动力学性能。在ZrCo合金表面构筑Pd/Cu复合金属涂层，提高合金抗毒化性能。在合金表面实现单/双金属超薄涂层可控制备，构筑高维度催化活性位点，建立表面结构与吸放氢特性构效关系。同时本项目研究了Ti/Hf合金元素联合取代对ZrCo合金储氢合金性能研究，Ti/Hf掺杂具有协调氢扩散作用，加速氢分子分解成氢原子，初始活化动力学明显提升，Ti/Hf共掺的ZrCo合金抗歧化性能提升，循环稳定性增强。结合先进表征手段及及第一性原理计算，揭示单/双金属超薄涂层协同催化合金吸放氢过程相关机制。本项目实施对改善ZrCo合金综合储氢性能有重要指导意义，对实现氢同位素快速供给技术具有实际应用价值。