Multiscale Self-Assembly of Nanoparticles into 3-Dimensional Photocatalysts

Multiscale nanoparticle assembly is at the heart of efforts to integrate nanoparticles into macroscopic materials and devices [1]. The idea of arranging nanoparticles in a modular and defined way to larger entities is extremely appealing, because in such a way a nearly indefinite number of different architectures is accessible from a limited set of building blocks. Among the many geometries, 3-dimensional structures like aerogels are unique in the sense that the size-specific properties of the nanobuilding blocks are fully preserved in the macroscopic material [2]. With their extensive porosity and large surface areas aerogels are particularly attractive for applications in gas-phase photocatalysis. However, to exploit the full potential of aerogels in photocatalysis, not only the composition of the aerogels, but also their macroscopic shape and the choice of reactor must be carefully matched to ensure efficient gas flow through and light penetration into the aerogel [3][4].<br/>In this presentation, a widely applicable strategy for the production of two-component aerogels with different geometries from colloidal dispersions of titanium dioxide and noble metal nanoparticles will be presented. Using the example of photocatalytic hydrogen production from methanol, it will be shown how these nanoparticle-based aerogels and the associated reactors can be improved step by step to significantly increase hydrogen production.<br/><br/>[1] M. Niederberger, <i>Multiscale Nanoparticle Assembly: From Particulate Precise Manufacturing to Colloidal Processing</i>, Adv. Funct. Mater. <b>2017</b>, <i>27</i>, 1703647<br/>[2] F. Matter, A.L. Luna, M. Niederberger, <i>From Colloidal Dispersions to Aerogels: How to Master Nanoparticle Gelation</i>, Nano Today <b>2020</b>, <i>30</i>, 100827<br/>[3] F. Matter, M. Niederberger, <i>The Importance of the Macroscopic Geometry in Gas-Phase Photocatalysis</i>, Adv. Sci. <b>2022</b>, <i>9</i>, 2105363<br/>[4] F. Matter, M. Niederberger, <i>Optimization of Mass and Light Transport in Nanoparticle-based Titania Aerogels</i>, Chem. Mater. <b>2023</b>, <i>35</i>, 7995