Boron-Doped Graphene/ZnO Nanoflower Heterojunction Composite with Superior Photocatalytic Activity

The boron-doped graphene (BG) is synthesized successfully by one pot reduce-doping of graphene oxide (GO) with borane tetrahydrofuran (BH₃·THF) and the novel BG/ZnO p–n heterojunction composite between p-type BG and n-type ZnO is obtained via a simple hydrothermal method. The samples are characterized by scanning electron microscopy, the Raman spectroscopy and the UV–Vis diffuse spectroscopy. The results confirm the formation of p–n junction between BG and ZnO. The photodegradation of MB demonstrate that the BG/ZnO composite has superior photocatalytic activity under UV–Vis or visible irradiation. The photocatalytic activity k value of BG/ZnO p–n heterojunction composite is 3.1 and 4.5 times as that of r-GO/ZnO and pure ZnO under white light and is 1.8 and 3.9 times under visible light, respectively. The superior photocatalytic activity of the BG/ZnO composite is ascribed to the formation of p–n heterojunction. The p–n heterojunction can promote the separation of electron/hole pairs and inhibit the recombination of electrons in conduction band and holes in valence band by transferring holes from the valence band of n-type ZnO to the valence band of p-type BG.