A General and Robust Route to Highly Diverse Hollow Nanostructures with New Properties

具有中空内部结构的纳米材料（即空心纳米材料）是许多科学技术领域的关键组成部分。空心纳米材料的性能及其在生物传感和催化等应用中的用途强烈依赖于其形状和元素组成等详细结构，并且可能与相同尺寸的固体颗粒不同。然而，如何在化学合成中精细地控制空心纳米材料的结构一直是一个挑战。该项目的目标是建立一种通用的、有效的方法来合成具有可控结构和新性能的空心纳米材料，该项目由材料研究部固体与材料化学项目和金属与金属纳米结构项目共同支持。除了合成新材料外，该项目还研究了热稳定性和与光的不寻常相互作用等特性，这些特性对最终的应用非常重要。该项目为研究生和本科生提供多学科研究培训，特别是来自代表性不足群体的学生。通过一项新的纳米大使计划，本科学生将在他们以前的高中参与纳米材料的推广。该项目还为高中生提供了暑期研究的机会。空心纳米材料在生物医学、成像、传感、催化和电子等领域有着广泛的应用。控制空心纳米结构的结构是调整其物理化学性质的有效途径。这项工作由材料研究部门的固态和材料化学项目以及金属和金属纳米结构项目共同支持，旨在开发一种通用且可靠的方法来精确控制空心纳米材料的结构。该方法依靠电替换反应和牺牲模板再生交替进行。例如，由金、银、铂、钯、铜和含有多种金属的材料制成的空心纳米结构的设计和合成正在得到演示。一系列具有不同结构和新性能的空心纳米结构正在产生。利用高性能电子显微镜研究了空心纳米材料的详细结构及其对加热的响应。利用实验测量和计算模拟研究了纳米材料的等离子体特性。这个项目将有利于研究生和本科生，特别是那些来自代表性不足群体的学生参与研究。这项研究也被整合到K-12学生的外展活动中。通过一项新的纳米大使计划，本科学生将在他们以前的高中参与纳米材料的推广。该项目还为高中生提供了暑期研究的机会。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Non-Technical Summary Nanoscale materials with hollow interiors (i.e., hollow nanomaterials) are critical components in many areas of science and technology. The properties of hollow nanomaterials and their usefulness in applications such as biosensing and catalysis have strong dependence on their detailed structure such as shape and elemental composition and can be different than those of solid particles of the same size. Nevertheless, it has been a challenge to finely control the structure of a hollow nanomaterial in chemical synthesis. The goal of this project, which is jointly supported by the Solid State and Materials Chemistry program and the Metals and Metallic Nanostructures program, both in the Division of Materials Research, is to establish a general and effective method to synthesize hollow nanomaterials with controllable structures and new properties. In addition to synthesizing new materials, this project examines properties such as thermal stability and unusual interactions with light that will be important for eventual applications. This project provides multidisciplinary research training for graduate and undergraduate students particularly from underrepresented groups. Through a new NanoAmbassadors program, undergraduate students will be involved in outreach on nanomaterials at their former high schools. The project also provides high school students with summer research opportunities.Technical SummaryHollow nanomaterials have found widespread uses in many areas, including biomedicine, imaging, sensing, catalysis and electronics. Controlling the structure of hollow nanostructures is an effective approach to tailoring their physicochemical properties. The proposed work, which is jointly supported by the Solid State and Materials Chemistry program and the Metals and Metallic Nanostructures program, both in the Division of Materials Research, seeks to develop a general and robust method to precisely control the structure of hollow nanomaterials. This method relies on alternating processes of galvanic replacement reactions and sacrificial template regeneration. As examples, design and synthesis of hollow nanostructures made of gold, silver, platinum, palladium, copper, and materials containing multiple metals are being demonstrated. A series of hollow nanostructures with diverse structures and new properties are being generated. Detailed structures of the hollow nanomaterials and their structural responses to heating are revealed with high-performance electron microscopy. Plasmonic properties of the nanomaterials are investigated using both experimental measurements and computational simulations. This project will benefit the engagement of graduate and undergraduate students, especially those from underrepresented groups, in research. The research is also integrated into outreach activities for K-12 students. Through a new NanoAmbassadors program, undergraduate students will be involved in outreach on nanomaterials at their former high schools. The project also provides high school students with summer research opportunities.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.