▎ 摘　　要

NOVELTY - Method for facile high-temperature colloidal synthesis of reduced graphene oxide and bismuth selenide nanoplates composite, comprises: synthesizing low-dimensional bismuth selenide nanoplates using the high-temperature colloidal synthesis method in which bismuth nitrate and sodium selenite pentahydrate was dispersed in ethylene glycol followed by stirring. The mixture was refluxed and allowed to cool to room temperature before being added to precipitate the bismuth selenide nanoplates with isopropyl alcohol. The product was subjected to washings with acetone and deionized distilled water to eliminate unreacted compounds and ethylene glycol, and then dried. The reduced graphene oxide/bismuth selenide nanoplates dispersed composite was prepared as, 0.05 g prepared bismuth selenide nanoplates, and reduced graphene oxide were added to deionized water. Finally, the mixture was ultrasonically treated for 3 hours. USE - The method is used for facile high-temperature colloidal synthesis of reduced graphene oxide and bismuth selenide nanoplates composite used as photocatalyst for degradation of organic dyes and inactivation of harmful bacteria for wastewater treatment. The synthesized reduced graphene oxide/bismuth selenide nanoplates composite is used as a photocatalyst to degrade the toxic organic dyes such as methylene blue (MB) and Rhodamine B. The synthesized reduced graphene oxide/bismuth selenide nanoplates composite is used as a photocatalyst to inactivate harmful bacteria such as Escherichia coli and Staphylococcus aureus in presence of visible light irradiation (all claimed). The composite is used as visible-light-driven photocatalyst and photodynamic therapy agent.No biological data is given. ADVANTAGE - The reduced graphene oxide/bismuth selenide nanoplates have high removal efficiency of 93-91% for MB and RhB even after three recycles which suggests that the fabricated material has high stability and sustainability. The 50 ppm of reduced graphene oxide/bismuth selenide nanoplates composite under 30 minutes of visible light irradiation causes almost 97-100% of bacterial killing efficiency. The composite has enhanced photocatalytic performance for bacterial destruction and dye degradation in wastewater treatment. The composite can significantly inhibit the growth of Staphylococcus aureusand Escherichia coli. The synthesized composite can kill the bacteria even in absence of light up and rupture the cell walls resulting in bacterial death. The composite is produced by facile high-temperature colloidal synthesis route. DETAILED DESCRIPTION - Method for facile high-temperature colloidal synthesis of reduced graphene oxide and bismuth selenide nanoplates composite, comprises: initially, synthesizing low-dimensional bismuth selenide nanoplates using the high-temperature colloidal synthesis method in which 1 mM of bismuth nitrate and 1.5 mM of sodium selenite pentahydrate was combined and dispersed in 35 mL of ethylene glycol followed by rigorous and continuous stirring for an hour. Then after, the mixture was refluxed at 260° C for 5 hours and allowed to cool to room temperature before being added to precipitate the bismuth selenide nanoplates with isopropyl alcohol. The product was subjected to multiple piles of washings with acetone and deionized distilled water to eliminate unreacted compounds and ethylene glycol, and then dried at 50° C for 6 hours in a hot air oven. Finally, the obtained bismuth selenide nanoplates powder is subjected to further characterizations. Later, reduced graphene oxide/bismuth selenide nanoplates dispersed composite was prepared as, 0.05 g prepared bismuth selenide nanoplates, and 0.05 g of previously prepared reduced graphene oxide using modified Hummer's method were added to 10 mL of deionized water. Finally, the mixture was ultrasonically treated for 3 hours in an Elmasonic S40 (ultrasonic cleaning unit), 140 W sonication bath.