Highly Selective, Active, and Stable Metal Nanoparticle Catalysts with Ultra-Thin Porous Ceramic Shells for Size-Selective Chemical Reactions

具有金属核和多孔壳结构的尺寸选择性催化剂可以通过反应物的分子区分来提高反应选择性。通过调节多孔膜的孔径大小可以提高催化剂的选择性。然而，选择性通常是以牺牲催化反应性为代价来提高的。拟议的项目旨在开发制备纳米结构尺寸选择性催化剂的方法，这些催化剂具有高选择性和活性。 所提出的尺寸选择性催化剂制备策略可以应用于各种负载型金属催化剂，也可以在其他领域找到应用，包括传感器，燃料电池，电池和超级电容器。本项目的主要目标是：（a）开发具有纳米尺寸的新型纳米结构尺寸选择性催化剂，（小于5 nm厚）多孔陶瓷覆盖层覆盖在每个金属纳米颗粒表面上，和（B）获得对催化剂的结构-活性-选择性关系的基本理解。一种独特的分子层沉积（MLD）技术将被用来合成具有精确的厚度控制和良好定义的多孔结构的高度多孔覆盖层。可以通过改变MLD化学、氧化物类型和多孔结构的形成方法来控制孔的尺寸。有一个计划，从这个项目的结果引入化学工程课程在密苏里州ST和开发一个新的课程：“纳米技术在催化”。研究生和本科生将被招募参加这一研究项目，特别强调通过与密苏里州的林肯大学-一个1890年历史上的黑人学院大学合作，招募代表性不足的少数民族。每年的“纳米材料展”将被开发和使用，以激发普通观众和K-12学生在化学工程和纳米技术领域的兴趣。该奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。

Size-selective catalysts with metal cores and porous shell structures can increase reaction selectivity through molecular discrimination of reactants. The selectivity of a catalyst can be improved by tuning the pore size of the porous films. However, selectivity is generally improved at the expense of catalytic reactivity. The proposed project is aimed at developing methods for preparing nanostructured size-selective catalysts that exhibit both high selectivity and activity. The proposed strategy for size-selective catalyst preparation can be applied to a great variety of supported metal catalysts and may also find applications in other fields, including sensors, fuel cells, batteries, and supercapacitors.The primary objectives of this project are: (a) to develop a novel nanostructured size-selective catalyst with a nanoscale (less than 5 nm thick) porous ceramic overlayer capped on every metal nanoparticle surface and (b) to gain a fundamental understanding of the structure-activity-selectivity relationships of the catalysts. A unique molecular layer deposition (MLD) technique will be utilized to synthesize the highly porous overlayers with precise thickness control and well-defined porous structures. The sizes of pores can be controlled by altering MLD chemistry, oxide types, and formation methods of porous structures. There is a plan to introduce results from this project into the Chemical Engineering curriculum at Missouri S&T and develop a new course: "Nanotechnology in Catalysis". Graduate and undergraduate students will be recruited to participate in this research project with special emphasis on recruiting underrepresented minorities through a collaboration with Lincoln University of Missouri - an 1890 Historically Black College & University. An annual " Nanomaterials Show" will be developed and used to stimulate interest of general audiences and K-12 students in the field chemical engineering and nanotechnology.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.