Synthesis of advanced titanium-organic hybrid aerogels

Kurzfassung

The ever-growing demand for sustainable and efficient energy solutions has accelerated the search for novel advanced materials with interesting electronic and catalytic properties. Among these materials, titanium dioxide (TiO2) has gathered significant attention due to its promising photocatalytic properties.[1] Due to the outstanding charge carrier separation properties of some TiO2 materials, they can also be used to store photogenerated electrons and conduct time-shifted photocatalysis.[2] For photocatalytic applications, nanomaterials, such as nanoparticles, are often favored over bulk materials because of their large surface area and high number of reactive sites.[1] However, the catalytic efficiency of nanoparticles usually decreases when agglomeration occurs, as the incident light can only excite the outer layer of the formed agglomerates, a significant ratio of active sites is lost. Nanostructured, porous aerogels with large surface areas are a promising approach to tackle this problem. Here the material particles are arranged in a rigid 3-dimensional network that prevents agglomeration and can be designed with sufficient light transmissibility that enables all incorporated particles to be excited upon radiation. The interconnected nature of the particles in aerogels can additionally improve the charge carrier separation in a material.[3,4] We will compare the sol-gel synthesis of titanium dioxide aerogels based on different catalysts and show the influence of different drying parameters on the material properties. We will discuss how different organic additives can alter the morphology and other properties of the material and thereby enable new forms of application. This includes the influence of denaturing agents in the used solvents, the synthesis of hybrid materials with bridging ligands, and the productions of hybrid inorganic-organic aerogel beads. Additionally, we will show how physical reinforcement can improve the material’s mechanical stability.

[1] K. Nakata et al., J. Photoch. Photobio. C 2012, 13, 169–189. [2] T. Berger et al., J. Phys. Chem. B 2005, 109, 6061–6068. [3] A. Rose et al., ACS Appl. Energy Mater. 2022, 5, 14966-14978. [4] A. Valaei et al., J. Chem. Eng. 2025, 524, 168924.