Departments of Biological Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, 76-561, Cambridge, Massachusetts 02139, USA.
Nanoscale. 2019 Jan 17;11(3):1091-1102. doi: 10.1039/c8nr04864a.
Porous metal nanofoams have made significant contributions to a diverse set of technologies from separation and filtration to aerospace. Nonetheless, finer control over nano and microscale features must be gained to reach the full potential of these materials in energy storage, catalytic, and sensing applications. As biologics naturally occur and assemble into nano and micro architectures, templating on assembled biological materials enables nanoscale architectural control without the limited chemical scope or specialized equipment inherent to alternative synthetic techniques. Here, we rationally assemble 1D biological templates into scalable, 3D structures to fabricate metal nanofoams with a variety of genetically programmable architectures and material chemistries. We demonstrate that nanofoam architecture can be modulated by manipulating viral assembly, specifically by editing the viral surface coat protein, as well as altering templating density. These architectures were retained over a broad range of compositions including monometallic and bi-metallic combinations of noble and transition metals of copper, nickel, cobalt, and gold. Phosphorous and boron incorporation was also explored. In addition to increasing the surface area over a factor of 50, as compared to the nanofoam's geometric footprint, this process also resulted in a decreased average crystal size and altered phase composition as compared to non-templated controls. Finally, templated hydrogels were deposited on the centimeter scale into an array of substrates as well as free standing foams, demonstrating the scalability and flexibility of this synthetic method towards device integration. As such, we anticipate that this method will provide a platform to better study the synergistic and de-coupled effects between nano-structure and composition for a variety of applications including energy storage, catalysis, and sensing.
多孔金属纳米泡沫在分离和过滤到航空航天等多种技术中做出了重大贡献。然而，为了充分发挥这些材料在储能、催化和传感应用中的潜力，必须对纳米和微尺度特征进行更精细的控制。由于生物体能自然地组装成纳米和微米结构，因此在组装生物材料上进行模板化可以实现纳米级结构控制，而无需替代合成技术所固有的有限化学范围或专用设备。在这里，我们将 1D 生物模板合理地组装成可扩展的 3D 结构，以制造具有各种遗传可编程结构和材料化学性质的金属纳米泡沫。我们证明，通过操纵病毒组装，特别是通过编辑病毒表面衣壳蛋白，以及改变模板密度，可以调节纳米泡沫的结构。这些结构在包括铜、镍、钴和金等贵金属和过渡金属的单金属和双金属组合在内的广泛组成范围内得以保留。还探索了磷和硼的掺入。与纳米泡沫的几何足迹相比，这种方法不仅将表面积增加了 50 倍以上，而且还导致平均晶体尺寸减小，并改变了与非模板对照相比的相组成。最后，将模板水凝胶沉积在厘米级范围内的一系列基板上以及独立的泡沫上，展示了这种合成方法在器件集成方面的可扩展性和灵活性。因此，我们预计这种方法将为研究各种应用（包括储能、催化和传感）中的纳米结构和组成的协同和去耦效应提供一个平台。
