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 center dot 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.