面向高效催化转化应用的纳米材料水合化学，表界面结构控制和稳定性研究

Most of oxide nanomaterials, featured by plenty of surface water molecules, suffer from dehydration and valence reduction of framework metal ions at high temperature and reduction conditions, which essentially lead to poor performance and therefore restrict the energy and environmental applications of many nanomaterials. On the basis of sufficient paper search and our preliminary research, we propose to study the interfacial hydration layer manipulation, interface strain control, surface hydroxyl groups induced metal-metal bonding tailoring and metal dispersion in ABOx(OH)y-based nanomaterials. By these, dehydration and framework metal valence reduction expect to be restrained, which may help to achieve highly efficient, stable nanomaterials in catalytic oxidation of CO at H2 enriched conditions from room temperature to 200 oC. Motivated by this, this project would try particle size reduction and surface structural modifications to produce a large amount of hydroxyl groups at the surfaces of ABOx(OH)y, while using high-temperature hydrothermal treatments to significantly increase the concentration of surface hydroxyl groups. By taking good use of the surface defects and dismatch of interfacial lattice, the interfacial tensile stress could be strengthened for promoting the hydroxyl groups absorption ability, while restraining the valence reduction. Furthermore, through the dispersion and stabilization roles of hydroxyl groups, bonding formed between noble metal ions and hydroxyl groups would be formed to enhance the interactions between noble metals and nanomaterials, thereby promoting the stabilization and functions of surface hydroxl groups. The outcome of this project would provide new routes for increasing the structural stability of nanomaterials at high temperature and reduction conditions, hopefully giving rise to new materials of high performance for energy and environmental applications.

氧化物纳米材料表面富含水分子，在高温还原条件下会出现脱水和骨架离子还原等现象，造成物化性能变差，制约其在能源及环境等高温还原条件下的应用。在大量文献调研和前期研究基础上，我们设想把ABOx(OH)y基纳米材料的表面水合分子层构筑、界面应力调控、表面羟基基团对金属键的剪切和金属分散作用相结合，抑制脱水和离子还原，获得近室温到200oC富氢条件下高效稳定的选择性催化氧化CO纳米材料。为此，本项目拟通过减小纳米尺寸和表界面掺杂结构改性等在ABOx(OH)y表面产生大量羟基；利用高温水热后处理进一步提高表面羟基浓度；基于表面缺陷和表面晶格失配的拉伸应力增强羟基吸附能力并抑制骨架离子还原；通过羟基对贵金属的分散和稳定作用，构建贵金属离子-羟基化学键，强化贵金属-纳米材料间相互作用，促进表面羟基的稳定性和功能化，探索出提升纳米材料在高温还原条件下结构稳定性的新途径，为能源及环境等应用提供高性能新材料。

氧化物纳米材料在能源及环境等高温还原条件下的应用面临挑战，而解决其在高温还原条件下脱水和骨架离子还原等问题是关键。通过富含羟基纳米材料的表面水合分子层构筑、界面应力调控、表面羟基基团对金属键的剪切和金属分散作用等研究，可望寻找到有效抑制脱水和离子还原的新方法，获得高效稳定的纳米催化材料，推动纳米材料在能源及环境等领域的应用。本项目开展了近室温或近室温富氢条件下选择性催化氧化CO应用的纳米材料的合成化学及构效关系研究。合成了Mg(OH)2、Al2Si2O5(OH)4•2H2O、MgFe2O4等多种富含羟基的层状金属氢氧化物、埃洛石纳米管和金属氧化物纳米材料, 全面考察了纳米尺寸（或厚度）和表界面复合与结构改性以及后续热处理等因素对羟基含量的作用，搭建了固体表面水合结构、贵金属或合金与固体材料的相互作用与表面氧物种活化能力之间的关系桥梁。通过系统研究，获得了对富含羟基的纳米材料的制备，几何尺寸的动力学控制，表界面复合与结构改性以及表面羟基的稳定性和功能化等相关科学问题的全新认识；揭示了表面羟基化机制及其相关的物理化学性质，对于深刻理解功能纳米复合材料体系中表界面的电子转移及其催化氧化性能变化规律产生重要借鉴作用，并获得了多种催化氧化性能优异的新型纳米复合材料。同时在国内外重要学术刊物上发表论文40余篇，申请发明专利4项，有7项发明专利在项目执行期间获得授权；培养从事纳米催化材料研究的博士生4名和硕士生1名。顺利完成了项目目标任务。