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, multiscale 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.