Metal-free black phosphorus nanosheets-decorated graphitic carbon nitride nanosheets with C-P bonds for excellent photocatalytic nitrogen fixation

Visible light photocatalytic nitrogen fixation, as a low-cost and mild technology, needs efforts to explore an economical photocatalyst with high activity and stability. In this study, a metal-free black phosphorus (BP) nanosheets-decorated graphitic carbon nitride nanosheets photocatalyst (BPCNS) has been successfully synthesized. With BP acting as the cocatalyst, BPCNS shows excellent performance in both visible light nitrogen photofixation and pollutant reduction owing to the increased number of excited electrons and enhanced separation efficiency of charge carriers through formation of C-P covalent bonds. Besides, the chemical structure of the BPCNS with optimal content of BP remains the same after exposure to air for 30 days or after five cycles of photocatalytic nitrogen fixation, since the occupation of the lone pairs on phosphorus atoms largely improves the chemical stability of BP.