Phosphorus quantum dots as visible-light photocatalyst for water splitting

Abstract

The discovery and synthesis of phosphorene stimulate the exploration of other two-dimensional (2D) phosphorus allotropes as well as phosphorus nanostructures. The recent successful preparation of phosphorene quantum dots further broadens the application areas of this novel 2D material. Herein we propose, for the first time, to sculpture monolayer black and blue phosphorus into quantum dots for photocatalytic solar water splitting. The size dependency of electronic, optical and photocatalytic properties of monolayer phosphorus quantum dots are systematically investigated. According to our first-principles calculations, these nanostructures possess highly tunable energy gap and work function; their frontier molecular orbitals straddle the water redox potentials with reasonable oxidizing and reducing power; they can harvest the full spectrum of visible light. Therefore, monolayer phosphorus quantum dots are promising candidates of visible-light photocatalysts for water splitting.