稀土基有序介孔材料的制备及贵金属纳米结构负载后等离子体共振增强光催化性能研究

Photocatalysts with large bandgaps typically have a low solar-to-hydrogen conversion efficiency because they absorb only a small proportion of solar photons. In addition, efficient photocatalysts need to allow for a facile separation of electron-hole pairs and their transport to the liquid/photocatalyst junction where the half-reactions are performed. However, recombination of photogenerated charge carriers always results in low photocatalytic activity. Rare earth elements have unique 4f electron structure and thus possess excellent optical, magnetic, and catalytic properties. The lanthanoids are renowned for being able to form complexes with various Lewis bases using their functional groups and the f-orbitals of the lanthanoids. Intergrated into semiconductor matrix, this may provide a means for pollutants to be adsorbed on the surface and enhance the photocatalytic activities. Doped with lathanoids, energy band configuration of traditional photocatalysts can be modulated to absorb more solar photons. Mesoporous structured materials possess high specific surface area, which provides more reactive sites at the surface for photocatalytic reaction to occur. The nanoscale channel wall of mesopores can facilitate the transfer of photogenerated electrons and holes to the surface, thus avoiding their recombination in the bulk. We seek support of this project for our exploration on synthesis of noble metal/rare earth ordered mesoporous materials and their application in photocatalysis. This research proposal puts forward a strategy to control the hydrolysis behavior of rare earth precursors in synthesis of ordered mesoporous structures by adding anions which have coordination abilities. Loading with noble metal nanostructures will allow us to combine the unique properties of rare earth mesoporous materials and plasmonic enhancement properties of noble metal nanostructures to achieve better photocatalytic activities.

传统宽带光催化剂材料由于能带结构限制，吸收光谱波段有限，同时电子-空穴对容易复合，导致其光能利用率和催化转化效率较低。稀土元素由于独特的4f 电子层结构，具有优异的光学、磁学和催化性质。稀土元素掺杂能够改进传统光催化剂的能带结构和表面化学性质，可实现多谱段的光能转化，在光催化领域显示出潜在的应用前景。而介孔结构由于高的比表面积、独特的纳米孔道结构和薄的孔壁厚度，可以提供更多的催化活性位点，提高光生电子和空穴向表面的传输，防止电子空穴的重新复合。本项目提出以具有配位作用的阴离子调节前驱体的水解行为，可控合成稀土基有序介孔材料。并负载贵金属纳米结构，获得贵金属/稀土基有序介孔复合材料，结合稀土的独特光催化性能，介孔结构的优势和贵金属的等离子体调节作用，实现对光催化剂吸收光效率和催化转化效率的改善。项目将对材料结构与光催化性能的关系做系统研究，为基于介孔稀土材料的新型光催化剂的开发打下基础。

发展新的、高效的光催化材料，获得低成本合成、高催化活性和高稳定性的光催化材料是发展光催化研究的关键目标。介孔纳米材料具有高的比表面积，能够提供大量的催化活性位点，此外，其独特的孔道结构和薄的孔壁厚度，提高了光生电子和空穴向表面的传输速度，防止了电子空穴的重新复合，在光催化中具有非常广泛的应用前景。稀土材料具有独特的光学和催化性质，能够有效提高光催化性能。申请人将稀土材料和介孔材料的优势相结合，发展了新的、高效的光催化剂体系。具体来说，申请人通过溶胶-凝胶法合成了稀土掺杂的有序晶态二氧化钛（TiO2）纳米颗粒，并提出了两性表面活性剂辅助产生中空结构的生长机理。申请人还基于CeO2和金纳米颗粒设计了一种核-壳-卫星状复合结构，实现了催化与上转换发光性质的多功能纳米集成，并对金纳米结构负载后等离子体共振增强氧化铈光催化性能进行了研究。此外，申请人还对项目研究内容进行了拓展，在介孔材料和稀土材料在电催化、生物医学领域的应用进行了研究。申请人以通讯作者身份在J. Am. Chem. Soc.、Angew. Chem. Int. Ed.、Adv. Mater.、ACS Nano.等杂志发表论文24篇，获批和申请专利4项，国内外邀请报告40余次，获得国家级、省部级人才支持计划5项（2013年新世纪优秀人才支持计划、2014年国家自然科学基金委优秀青年科学基金、2014年第二批中组部万人计划青年拔尖人才支持计划、2015年中国化学会青年化学奖、2015年教育部长江学者青年学者），培养已毕业硕士研究生6名。