Design And Photocatalytic Performance Of Bi-based Composite Semiconductor Photocatalyst

Bismuth subcarbonate(Bi2O2CO3)is a Aurivillius oxide and consists of alternating[Bi2O2]2+ and CO32-layers.Bi2O2CO3 is a promising photocatalyst for the degradation of organic dyes,but it has 2.87-3.5 eV band gap and can only absorb less than 5%UV-light.Therefore,it is important to enhance its visible light optical response.In this paper,Bi2O2CO3 photocatalyst was prepared by a simple hydrothermal method.In order to enhance its response to visible light,it was combined with CdS QDs,Bi2S3,Zn0.5Cd0.5S,respectively,and their photocatalytic performance were discussed.(1)A serie of flower-like CdS QDs/Bi2O2CO3 composite photocatalysts were prepared by a two-step method.The series samples were compounded with different amounts of CdS QDs.We studied the phase structure,morphology,optical properties,stability and photocatalytic activity of the prepared samples.The result of UV-vis diffuse reflectance test show that the light absorption range extends from 400 nm to 575 nm.The result of photocatalytic degradation of RhB under visible light showed that RhB could degrade by 10 wt%CdS QDs/Bi2O2CO3 composite photocatalyst about 45%in 120 min,and that of pure Bi2O2CO3 was only about 10%,which confirmed its enhancement.(2)Zn0.5 Cd0.5S and Bi2O2CO3 photocatalysts were prepared by simple hydrothermal method respectively,and then different amounts of Zn0.5Cd0.5S and Bi2O2CO3 were combined by deposition.The result of UV-vis diffuse reflectance test show that the light absorption range extends from 400 nm to 525 nm.The photocatalytic activity was evaluated by photocatalytic degradation of RhB under visible light,and RhB could degrade by 10 wt%Zn0.5Cd0.5S/Bi2O2CO3 composite photocatalyst about 65%in 120 min,which confirmed its improvement.(3)Based on that B12O2CO3 nanoflowers were prepared by a simple one-step hydrothermal method,and then Bi2S3/Bi2O2CO3 heterojunction photocatalyst was prepared by ions exchange to obtain S2-ions with Bi3+ on Bi2O2CO3 nanoflowers to form B12S3.The result of UV-vis diffuse reflectance test show that the light absorption range extends from 400 nm to over 800 nm.The photocatalytic activity was studied by photocatalytic degradation of RhB under visible light.In addition,the effects of S2"concentration and reaction time on photocatalytic activities were analyzed.Among them,RhB could be degraded by 4,1 Bi2S3/Bi2O2CO3 with best performance about 95%in 120 min,which presented its enhancement compared with pure B12O2CO3 nanoflower.