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. Structural replication and surface reduction are investigated to afford freestanding mesoporous black titania with nanoscale helicity and its electrochemical properties for lithium‐ion batteries are evaluated.