Structural, Optical and Photocatalytic Activity of Multi-heterojunction BiO/BiOCO/(BiO)CO(OH) Nanoflakes Synthesized via Submerged DC Electrical Discharge in Urea Solution.

In this research, a novel ternary multi-heterojunction BiO/BiOCO/(BiO)CO(OH) photocatalyst is fabricated via submerged DC electrical arc discharge in urea solution. FT-IR, XRD, EDS and PL results confirm the formation of BiO/BiOCO/(BiO)CO(OH) multi-heterojunction. Formation of nanoflake morphology is revealed by FE-SEM and TEM images. The optical properties and intense absorption edge of BiO/BiOCO/(BiO)CO(OH) reveal the proper visible light absorbing ability. The photocatalytic performance of the sample is investigated via the degradation of methylene orange (MeO) and rhodamine B (RB) under visible light irradiation. The photocatalytic activity of BiO/BiOCO/(BiO)CO(OH) is compared with the synthesized sample in water, BiO/Bi/Bi(OH) which exhibits much higher photocatalytic activity. Also, the stable photodegradation efficiency of BiO/BiOCO/(BiO)CO(OH) after four cycles reveals the long-term stability and reusability of the synthesized photocatalyst. The PL intensity of BiO/BiOCO/(BiO)CO(OH) shows an improved separation rate of electron-hole pairs and so enhanced photocatalytic performance. The improved photocatalytic activity can be ascribed to the formation of multi-heterojunctions, flake morphology and intrinsic internal electric field (IEF). Multi-heterojunction nanoflakes enhance the absorbance of visible light and facilitate the separation and transport of photogenerated electron holes through large IEF. Our work offers an effective method for the production of innovative bismuth-based photocatalyst with excellent prospects for the degradation of environmental pollutants and light harvesting for renewable energy generation under visible light.