Controlling Self-Assembly of Cellulose Nanocrystal to Synergistically Regulate (001) Reactive Facets and Hierarchical Pore Structure of Anatase Nano-TiO2 for High Photocatalytic Activity

As one of the most efficient and environmentally benign strategies to treat organic dye pollution, TiO2 photocatalytic technology has attracted increasing and wide interests in environmental governance, for which dominantly exposed (001) facets and high porosity are of great importance for catalytic performance. To date, however, how to synergistically regulate the dominant growth of (001) facets and the formation of hierarchical pore structures still remains challenging. Here, we report a limited growth strategy mediated by the self-assembly of cellulose nanocrystal (CNC) to prepare anatase TiO2 nanocatalyst with dominantly exposed (001) reactive facets. Notably, crystal growth in the confined space of layered CNC structures favors exposing (001) facets, and the easy removal of the soft biotemplate facilitates creating hierarchical pores. Furthermore, the (001) facet percentage, pore size, and porosity can be easily modulated by controlling the CNC concentration. After introducing an up-conversion quantum dot as the energy donor, the nanocatalyst can catalyze the degradation of rhodamine B efficiently under visible light irradiation. Such finding indicates that this biotemplating approach will be of great value to develop new functional environmental catalysts with desirable structures and properties.