Electrochemical processing of discrete nanoparticle ions

高质量的，纯化的纳米粒子是基础科学研究和各种（分层）功能材料的技术应用所必需的。碳纳米管是一种典型的纳米粒子，如果能够克服剩余的加工障碍，它将具有巨大的前景。一种最近的路线通过在金属-氨溶液中使用化学充电以形成“纳米管”阴离子来解决这一挑战。充电独特地提供了一种方法，以真正的热力学平衡解决方案的单壁纳米管，并已被证明提供了一种手段，以消除无定形碳和分离金属从半导体馏分;这项技术已经获得商业许可，是一个新的合资企业的主题。然而，在开发了这种方法之后，我们意识到可以通过使用纯电化学充电来避免具有挑战性的碱金属-氨溶液。这种方法代表了一种全新的纳米粒子处理策略，通过电化学溶解和随后的离散纳米粒子离子的电沉积。我们相信，这种方法将是通用的，可能适用于各种电化学稳定的导电纳米颗粒，可能包括贵金属系统，石墨烯和一些过渡金属硫属化物;它提供了无与伦比的电荷密度和化学势控制。这些结果提出了关于离散纳米颗粒电化学的可能性以及与传统原子/离子系统的潜在类比的基本科学问题。他们还提出了新的大规模制造工艺的机会，涉及纳米颗粒，特别是纯化（分馏），功能涂层或复合材料/混合物的共沉积。值得注意的是，许多大规模工业过程依赖于电化学方法，包括铜的纯化和铝的电解提取。纳米粒子离子本身为进一步的化学反应或组装提供了机会。例如，纳米管阴离子对亲电试剂具有反应性，提供了一种以高产率产生官能化的单个物质的方法。精确操纵电荷密度和电势的能力，加上对这些材料复杂态密度的理解，将使这种新的化学被理解、控制和开发。简而言之，该项目将探索一个新的方向：通过电化学加工形成定义明确的离散离子所带来的科学挑战和技术机遇。

High quality, purified nanoparticles are required for both fundamental scientific studies and technological applications in a variety of (hierarchical) functional materials. Carbon nanotubes are an archetypical nanoparticle with enormous promise if the remaining processing hurdles can be overcome. One recent route addresses this challenge by using chemical charging in metal-ammonia solutions to form "nanotubide" anions. Charging uniquely provides an approach to true thermodynamic equilibrium solutions of single walled nanotubes, and has proved to offer a means both to remove amorphous carbon and to separate metallic from semiconducting fractions; this technology has already been licensed commercially and is the subject of a new venture. However, having developed this methodology, we realised that the challenging alkali metal-ammonia solution can be avoided by using pure electrochemical charging. This approach represents an entirely new strategy for nanoparticle processing, through electrochemical dissolution and subsequent electrodeposition of discrete nanoparticle ions. We believe that the approach will be general and may be applicable to a variety of electrochemically stable, conductive nanoparticles, likely including noble metal systems, graphene, and some transition metal chalcogenides; it offers unrivalled control of charge density and chemical potential. The results raise fundamental scientific questions about the possibility of discrete nanoparticle electrochemistry and potential analogies to traditional atomic/ionic systems. They also suggest opportunities for new large scale manufacturing processes involving nanoparticles, particularly purification (fractionation), functional coatings or co-deposition of composites/hybrids. It is worth noting that many large scale industrial processes rely on electrochemical approaches, including the purification of copper, and electrowinning of aluminium. The nanoparticle ions themselves offer opportunities for further chemical reactions or assembly. As an example, nanotubide anions are reactive to electrophiles, offering a means to generate functionalised individual species in high yield. The ability to manipulate charge density and potential accurately, coupled with an understanding of the complex density of states of these materials, will allow this new chemistry to be understood, controlled and exploited.In short, this project will explore a new direction: the scientific challenges and technological opportunities enabled by the formation of well-defined discrete ions through electrochemical processing.