Nanocrystalline Transition-Metal Oxide Spheres with Controlled Multi-Scale Porosity

This article presents original multi‐scale porous nanocrystalline transition‐metal oxide materials (MO2, where M = Ti, Zr, Ce) that have many potential applications. They were prepared through a one step method that combines sol–gel chemistry, multi‐scale templating approaches, aerosol processing, and specific treatments. The final material presents itself as spheres of controlled diameter, made of a periodically organized mesoporous crystalline network that surrounds spherical macropores, in which each single porosity can be easily and independently adjusted. In addition, a porosity gradient can be generated. The strategy highlighted here can be easily applied to many hierarchically structured sol–gel derived materials. Moreover, this process can easily be scaled up, which could lead to a breakthrough in the industrial production of innovative multiscale porosity materials. Industrial production of innovative multiscale porosity materials could be facilitated by the new and easily scaled‐up process reported here. Nanocrystalline transition‐metal oxide spheres of hierarchically and periodically organized porosity (see Figure) have been prepared through a one‐step method that combines sol–gel chemistry, multiscale templating approaches, aerosol processing, and specific treatments.