Department of Chemistry, Simon Fraser University, 8888 University Drive, Burnaby, B.C. V5A 1S6, Canada.
Nanoscale. 2019 Jan 23;11(4):1937-1948. doi: 10.1039/c8nr07762b.
The incorporation of catalytic nanocrystals into macroporous support materials has been very attractive due to their increased catalyst mass activity. This increase in catalytic efficiency is attributed in part to the increased surface area to volume ratio of the catalysts and the use of complementary support materials that can enhance their catalytic activity and stability. A uniform and tunable coating of nanocrystals on porous matrices can be difficult to achieve with some techniques such as electrodeposition. More sophisticated techniques for preparing uniform nanocrystal coatings include atomic layer deposition, but it can be difficult to reproduce these processes at commercial scales required for preparing catalyst materials. In this study, catalytic nanocrystals supported on three dimensional (3D) porous structures were prepared. The demonstrated technique utilized scalable approaches for achieving a uniform surface coverage of catalysts through the use of polymeric sacrificial templates. This template assisted technique was demonstrated with a good control over the surface coverage of catalysts, support material composition, and porosities of the support material. A series of regular porous supports were each prepared with a uniform coating of nanocrystals, such as NaYF4 nanocrystals supported by a porous 3D lattice of Ti1-xSixO2, Pt nanocrystals on a 3D porous support of TiO2, Pd nanocrystals on Ni nanobowls, and Pt nanocrystals on 3D assemblies of Au/TiO2 nanobowls. The template assisted preparation of high surface area macroporous supports could be further utilized for optimizing the use of catalytic materials in chemical, electrochemical, and photochemical reactions through increasing their catalytic efficiency and stability.
将催化纳米晶纳入大孔支撑材料中由于其增加的催化剂质量活性而非常有吸引力。这种催化效率的提高部分归因于催化剂的表面积与体积比的增加，以及使用互补的支撑材料可以增强其催化活性和稳定性。用一些技术，如电沉积，在多孔基质上均匀且可调的纳米晶涂层可能很难实现。制备均匀纳米晶涂层的更复杂技术包括原子层沉积，但在商业规模上重现这些过程以制备催化剂材料可能很困难。在本研究中，制备了负载在三维（3D）多孔结构上的催化纳米晶。所展示的技术利用可扩展的方法，通过使用聚合牺牲模板来实现催化剂的均匀表面覆盖。通过这种模板辅助技术，可以很好地控制催化剂的表面覆盖率、支撑材料的组成和支撑材料的孔隙率。一系列规则多孔支架都用纳米晶均匀涂层进行了制备，例如，由 Ti1-xSixO2 多孔 3D 晶格支撑的 NaYF4 纳米晶、TiO2 多孔 3D 支架上的 Pt 纳米晶、Ni 纳米碗上的 Pd 纳米晶和 3D 组装的 Au/TiO2 纳米碗上的 Pt 纳米晶。通过增加其催化效率和稳定性，可以进一步利用高表面积大孔支撑材料的模板辅助制备来优化催化材料在化学、电化学和光化学反应中的应用。
