Recent Advances in Black TiO Nanomaterials for Solar Energy Conversion.

Titanium dioxide (TiO) nanomaterials have been widely used in photocatalytic energy conversion and environmental remediation due to their advantages of low cost, chemical stability, and relatively high photo-activity. However, applications of TiO have been restricted in the ultraviolet range because of the wide band gap. Broadening the light absorption of TiO nanomaterials is an efficient way to improve the photocatalytic activity. Thus, black TiO with extended light response range in the visible light and even near infrared light has been extensively exploited as efficient photocatalysts in the last decade. This review represents an attempt to conclude the recent developments in black TiO nanomaterials synthesized by modified treatment, which presented different structure, morphological features, reduced band gap, and enhanced solar energy harvesting efficiency. Special emphasis has been given to the newly developed synthetic methods, porous black TiO, and the approaches for further improving the photocatalytic activity of black TiO. Various black TiO, doped black TiO, metal-loaded black TiO and black TiO heterojunction photocatalysts, and their photocatalytic applications and mechanisms in the field of energy and environment are summarized in this review, to provide useful insights and new ideas in the related field.