A Low-Cost Metal-Free Photocatalyst Based on Black Phosphorus

An efficient metal-free photocatalyst composed of black phosphorus (BP) and graphitic carbon nitride (CN) is prepared on a large scale by ball milling. Using economical urea and red phosphorus (RP) as the raw materials, the estimated materials cost of BP/CN is 0.235 Euro per gram. The BP/CN heterostructure shows efficient charge separation and possesses abundant active sites, giving rise to excellent photocatalytic H₂ evolution and rhodamine B (RhB) degradation efficiency. Without using a co-catalyst, the metal-free BP/CN emits H₂ consistently at a rate as large as 786 µmol h⁻¹ g⁻¹ and RhB is decomposed in merely 25 min during visible-light irradiation. The corresponding electron/hole transfer and catalytic mechanisms are analyzed and described. The efficient metal-free catalyst is promising in visible-light photocatalysis and the simple ball-milling synthetic method can be readily scaled up.