Nano Black Titania and Solar Applications

Searching of efficient semiconductor photocatalysts utilizing visible-light solar energy for hydrogen generation from water splitting remains a great challenge. Many efforts have been focused on enhancing visible light absorption by narrowing the bandgap of TiO₂, but their visible-light power conversion still remains insufficient. Here we report a new low-temperature approach to synthesize black titania with a unique amorphous core/crystalline shell structure (TiO₂@TiO_2-x). This black titania improves visible and infrared light absorption and ultra-visible light photocatalytic activity. More importantly, the incorporation of nonmetal elements (X = H, N, S, I) into the shells significantly boosts visible-light photocatalytisis on both water splitting and waste-water cleaning. It is worth noting that the amorphous shell and the X termination as a strategy are necessary for titania to narrow bandgap and receive more efficient visible-light photocatalysis than any other reported titania.