A facile route to synthesize boron-doped g-C3N4 nanosheets with enhanced visible-light photocatalytic activity

The boron-doped g-C3N4 nanosheets (BCNNs) have been successfully synthesized via an ultra-rapid and environment-friendly microwave heating route. The reaction system is quite simple, using boric-acid-modified melamine as raw materials and carbon fibers as microwave absorbent, respectively. Based on the optical characterizations and calculation, the results show an abnormal phenomenon that the introduction of B element into g-C3N4 host leads to the increase in band gap. The enlarged band gap should be ascribed to the quantum confinement effect derived from the special nanosheets microstructure of the obtained BCNNs. For the visible-light photocatalytic experiment, 92.9% rhodamine B can be degraded at room temperature in just 30 min in the presence of BCNNs, and the photodegradation rate constant of BCNNs is 3.3 times that of the pure g-C3N4 (PCN). In comparison with the PCN, the enhanced photocatalytic activity of BCNNs can be attributed to the more satisfactory mesoporous structure, larger surface-to-volume ratio, and higher charge separation.