Nanospiked Particles for Photocatalysis

密歇根大学安娜堡分校的尼古拉斯·科托夫教授在化学系化学催化计划的支持下，开发了光催化纳米颗粒作为一种新型的多相纳米催化剂。这些颗粒是由氧化锌(ZnO)针组成的，这是一种高活性材料，暴露在光下时用于加速(催化)反应。针生长在球形核心周围，能够在爱水和讨厌水的液体中形成悬浮液。具有纳米棒表面的粒子的主要优势是它们能够在亲水的溶剂中分散和进行反应，同时保持其亲水的表面状态。在大多数情况下，纳米光催化剂提高了效率和选择性，降低了能源成本，并简化了许多重要工业过程的制造操作。许多纳米光催化剂只能在水和其他极性溶剂中工作，重要的起始原料和反应产物只能与非极性(憎水)溶剂兼容。纳米颗粒的光催化能力可能会提高塑料制造的效率。这些材料还可能开辟新的反应途径，改善化学和制药生产。在这项研究的过程中，研究生和本科生接受纳米科学和催化方面的先进研究方法的培训。与密歇根地区伊普萨兰蒂学区的科学和艺术教师建立了一个合作项目，以设计新的教学项目，将艺术和科学结合起来，帮助提高人们对纳米科学和技术的兴趣。通过在二氧化硅、氧化铝和二氧化钛微米级芯材上生长氧化锌纳米棒，制备了全方位分散的纳米颗粒。测试了这些催化粒子在有机溶剂中的转化率和选择性，并用于环己烷的光氧化制环己醇和环己酮，这是许多常见聚合物大规模生产的关键前体。对反应机理和反应动力学进行了研究。此外，还进行了详细的实验和理论模拟研究，以期对纳米颗粒的催化活性有一个基本的了解，并为开发无机、胶体、多相光催化剂的工程基础奠定基础。

Professor Nicholas Kotov of the University of Michigan Ann Arbor is supported by the Chemical Catalysis program of the Division of Chemistry to develop photocatalytic nanospiked particles as a new type of heterogeneous nanocatalysts. These particles are made of zinc oxide (ZnO) needles, a highly active material, used to speed up (catalyze) reactions when exposed to light. The needles are grown around a spherical core that have the ability to form suspensions in both water-loving and water-hating liquids. The main advantage of particles with a surface of nanospikes is their ability to disperse and conduct reactions in water-hating solvents while retaining their water-loving surface states. In most cases, nanoscale photocatalysts improve efficiency and selectivity, reduce energy costs and simplify manufacturing operations for many important industrial processes. Many nanoscale photocatalysts work only in water and other polar solvents important starting materials and reaction products are only compatible with nonpolar (water-hating) solvents. The ability of nanospiked particles to perform photocatalysis may improve the efficiency of plastics manufacturing. These materials may also open up new reaction pathways and improve the chemical and pharmaceutical production. During the course this research, graduate and undergraduate students are trained in advanced research methods in nanoscience and catalysis. A collaborative program with science and art teachers in the Ypsalanti, Michigan area school district is established to devise new teaching and learning projects that combine art and science to help promote interest in nanoscience and technology. The omnipdispersive nanospiked particles are synthesized by growing ZnO nanorods on silica, alumina and titania microscale cores. The utility of these catalytic particles in organic solvents with respect to conversion rate and selectivity are tested for the photooxidation of cyclohexane to cyclohexanol and cyclohexanone, which are the key precursors for the large scale production of many common polymers. The reaction mechanism and kinetics are investigated. In addition, detailed experimental and theoretical modelling studies are conducted to arrive at a basic understanding of the catalytic activity of nanospiked particles and to develop an engineering foundation of inorganic, colloidal, heterogeneous photocatalysts.