Self-assembled B-doped flower-like graphitic carbon nitride with high specific surface area for enhanced...

Graphitic carbon nitride (g-C₃N₄) is a promising nonmetallic photocatalyst. In this manuscript, B-doped 3D flower-like g-C₃N₄ mesoporous nanospheres (BMNS) were successfully prepared by self-assembly method. The doping of B element promotes the internal growth of hollow flower-like g-C₃N₄ without changing the surface roughness structure, resulting in a porous floc structure, which enhances the light absorption and light reflection ability, thereby improving the light utilization rate. In addition, B element provides lower band gap, which stimulates the carrier movement and increases the activity of photogenerated carriers. The photocatalytic mechanism and process of BMNS were investigated in depth by structural characterization and performance testing. BMNS-10 % shows good degradation for four different pollutants, among which the degradation effect on Rhodamine B (RhB) reaches 97 % in 30 min. The apparent rate constant of RhB degradation by BMNS-10 % is 0.125 min^-1, which is 46 times faster compared to bulk g-C₃N₄ (BCN). And the photocatalyst also exhibits excellent H₂O₂ production rate under visible light. Under λ > 420 nm, the H₂O₂ yield of BMNS-10 % (779.9 μM) in 1 h is 15.9 times higher than that of BCN (48.98 μM). Finally, the photocatalytic mechanism is proposed from the results of free radical trapping experiments.