纳米TiO2/Mg2Ni复合材料的制备与光解水制氢储氢协同作用研究

This project aims to prepare composites of nano-TiO2 photocatalyst and Mg2Ni hydrogen storage alloys where the nano-TiO2 photocatalyst can absorb visible light to split water to produce hydrogen and then the Mg2Ni hydrogen storage alloys can storage the in-situ produced hydrogen. We will investigate the synergetic effect of hydrogen generation and storage on such novel composites. We want to develop a simple and integrated technology for hydrogen generation and storage. It means that hydrogen can be stored in hydrogen storage alloy as soon as the photocatalytic hydrogen production happens, and the sacrificial agent will be recycled at the same time. It is necessary to modify the TiO2 photocatalyst so that it can be responsive to a wider range of the spectrum, particularly in the visible range. Since Mg2N alloy usually shows poor dynamic performance and cycling stability, we will also develop technologies to improve the properties of the hydrogen storage alloys. Then the effect between hydrogen productin and storage will be investigated to get a highly reactive composite material. An evaluation method will be developed to examine the comprehensive performance of this composite material such as hydrogen production rate, hydrogen storage capacity and stability. The co-relationship between structure and properties of composite photocatalysts will be established to guide the design and fabrication of novel energy materials.

本项目主要研究具有宽光谱响应的改性纳米TiO2材料光解水制氢光催化剂和常温吸放氢Mg2Ni贮氢合金复合材料的制备及其制氢储氢协同作用。研制光解水制氢贮氢一体化材料，将光解水产生的氢即时储存起来，再通过可控途径得到高纯度氢气，集氢能生产与储存一体化；通过掺杂改性纳米TiO2材料宽光谱响应光解水制氢催化剂和纳米晶态与非晶态Mg2Ni贮氢合金复合材料的制备以及协同作用研究，制得高反应活性与宽光谱响应的光解水制氢、储氢一体化复合材料；建立光解水制氢与储氢一体化循环反应体系，连续产氢、储氢，并实现牺牲剂的循环使用；建立光解水制氢、储氢一体化复合材料检测评价方法；探讨宽光谱响应光解水催化剂材料结构与性能的关系及光解水制氢储氢复合材料光催化作用与储氢作用的协同关系。

本项目研究了具备光充电性能的TiO2/Mg2Ni光催化制氢储氢一体化复合材料，探讨光解水制氢催化剂与储氢合金的相互影响及其制氢储氢协同作用机理。通过X射线衍射（XRD），扫描电子显微镜（SEM），透射电子显微镜（TEM）及X射线能量散射谱（EDS）等技术，考察了复合材料的微观结构与形貌；测试了光催化剂的光催化行为，储氢合金电化学性能和复合光电极光充电行为等，验证了TiO2/Mg2Ni光电极可实现光充电，小电流辅助光照充电提高光充电的效率；提出了光催化剂与储氢合金复合这样一种光催化制氢储氢一体化的储能新方法及新技术。.溶胶包覆法制备的异质结SrZr0.95Y0.05O3-TiO2-xNx复合光催化剂在模拟太阳光条件下有较好的光催化产氢活性，其催化活性明显高于纯的SrZr0.95Y0.05O3和TiO2。在最佳负载量1wt%下，平均产氢速率达到2.1mmol·g·cat-1h-1。采用水热-无模板法得到了得到分布均匀且大小约为0.5~1 μm的TiO2-ZnO-Zn2TiO4复合微球，降解MO的脱色率以及表观反应速率分别为88.4%和8.131×10-2 min-1。TiO2和TiO2-ZnO-Zn2TiO4复合微球的带隙分别为3.24 eV与3.14 eV，发生了少许红移。.采用熔体快淬法(RQ)及磁场作用下熔体快淬法(MFRQ)处理了稀土–Mg–Ni型La0.1Nd0.075Mg0.04Ni0.65Co0.12储氢合金。随着淬速的提高和磁场的施加，合金晶粒得到细化，合金的抗粉化性能提高，合金的充放电循环性能改善。相比快淬法制备的合金，当施加了磁场后，合金的La2Ni7 相丰度增大，放电容量增大。采用简易的浸渍煅烧法制备不同银负载量的Ag-TiO2催化剂并通过涂覆法涂覆在La0.1Nd0.075Mg0.04Ni0.65Co0.12合金制备了AT/MH电极。AT/MH光电极实现光充电，在不外加电流紫外光照射后充电后电压从-0.5180 V降到-0.5425 V (vs. Hg/HgO)。然而充电后期，由于空穴氧化合金，光充电受阻。采用简易煅烧法制备g-C3N4/TiO2催化剂并制备了CT/MH电极。光降解和瞬态电流测试表明g-C3N4/TiO2的光催化性能提高。这是因为异质结的形成促进了光生载流子的分离。CT/MH光电极能实现光充电，在外加电流的促进下光充电的效率提高。