Visible-light-active elemental photocatalysts.

Seeking visible-light-active photocatalysts for efficient solar-energy conversion has become an intensifying endeavor worldwide. In this concept paper, general requirements for finding new visible-light-active photocatalysts are briefly introduced, and recent progress in exploring elemental photocatalysts for clean-energy generation and environmental remediation are reviewed. Finally, opportunities and challenges facing elemental photocatalysts are discussed.