Black Titania with Nanoscale Helicity

The fabrication of mesoporous black titanium dioxide (TiO2-x) with a chiral nematic organization of core-shell nanorods is reported. Chiral templating of TiO2 nanoparticles onto gelatin-functionalized cellulose nanocrystals (CNCs) followed by calcination yields carbonized TiO2/CNC helical materials that recover white TiO2 replicas after carbon removal. The hydrothermal surface reduction of the traditional white TiO2 by ascorbic acid affords freestanding chiral nematic black TiO2-x. The black TiO2-x is a visible light active semiconducting mesoporous structure constructed by chiral nematic crystalline-amorphous TiO2 core-shell nanorods. The chiral black TiO2-x nanoparticles supported on mesoporous nanocarbon networks are evaluated as lithium-ion battery anode electrodes. Beyond the current efforts, these black TiO2-x materials and their composites may be useful in the fields of energy storage and catalysis.