A sol-gel biotemplating route with cellulose nanocrystals to design a photocatalyst for improving hydrogen generation

Light harvesting capability and charge carrier lifetime play critical roles in determining the photoefficiency of a photocatalyst. Herein, a one-pot method is proposed to design mesostructured TiO2 materials by taking advantage of the ability of cellulose nanocrystals (CNCs) to self-assemble into chiral nematic structures during solvent evaporation. After the xerogel formation, the as-obtained CNC/TiO2 hybrid films exhibit a chiral nematic structure and tunable Bragg peak reflection, generating a lamellar TiO2 mesostructure after the biotemplate removal by calcination. More prominently, this straightforward method can be extended to couple TiO2 with other metal oxides, improving the light-harvesting and charge carrier separation of these photocatalysts, in particular for improving hydrogen generation. This foolproof approach opens new doors for the development of nanostructured materials for solar energy conversion and catalysis.