Synthesis And Visible Light Photocatalytic Performance Research Of BiOCOOH-based Composite Photocatalysts

Photocatalytic technology has attracted more and more attention because of its advantages of energy saving,high efficiency,strong oxidation ability and green environmental protection in environmental pollution control.It is found that BiOCOOH is a novel bismuth-containing photocatalyst which has potential application value in photocatalysis due to its unique layered structure.However,due to its large band gap and low utilization rate of sunlight,its practical application is limited.Hence by a combination with narrow-band semiconductors WO3 and AgI respectively to improve its photocatalytic activity.The WO3/BiOCOOH composite photocatalysts were synthesized by secondary hydrothermal method.The Agl/BiOCOOH composite photocatalysts were synthesized by hydrothermal and precipitation method.And these photocatalysts were characterized by XRD,SEM,TEM,UV-Vis DRS and BET.Through the photocatalytic degradation experiment of Rhodamine B under visible light,the optimal preparation conditions of WO3/BiOCOOH and AgI/BiOCOOH were selected,and the influencing factors and reusability of visible light catalytic degradation of Rhodamine B were further investigated.The research results of this paper show that:(1)When the precursor liquid pH is 1.8,120? hydrothermal 16 h,and the compound molar ratio n(WO3):n(BiOCOOH)=0.4:1,the prepared WO3/BiOCOOH composite photocatalyst has the best visible light photocatalytic degradation effect.After 90 min illumination,the degradation effect of WO3/BiOCOOH was 2.8 and 8.7 times that of BiOCOOH and WO3,respectively.(2)The photocatalytic degradation of Rhodamine B by WO3/BiOCOOH composite photocatalyst showed that when the dosage of the catalyst was 0.5g/L,the solution concentration was 20 mg/L,and the pH was acidic,the photocatalytic degradation effect is the best,and the decolorization rate can reach 95%after 90 min illumination.The addition of NaCl will reduce the photocatalytic degradation effect;the composite photocatalyst has better repeatability;the degradation reaction of Rhodamine B conforms to the first-order reaction kinetics equation,and as the initial concentration increases,the apparent rate constant gradually decreases.(3)The synthesized AgI/BiOCOOH composite photocatalyst has the best photocatalytic activity when the precursor liquid pH is 1.8,120? hydrothermal for 16h,and m(AgI):m(BiOCOOH)=60%.After 30 min illumination,the degradation effect of AgI/BiOCOOH on Rhodamine B was 7.4 times that of BiOCOOH and 1.6 times that of AgI.(4)The photocatalytic degradation of Rhodamine B by AgI/BiOCOOH composite photocatalyst showed that when the dosage of the catalyst was 0.5g/L,the concentration of solution was 15 mg/L,and the pH was acidic,the photocatalytic degradation effect is the best,and the decolorization rate can reach 95%after 30 min illumination.The addition of NaCl will slightly reduce the photocatalytic degradation effect;the composite photocatalyst has good stability and can be used repeatedly;the degradation reaction of Rhodamine B accords with the first-order reaction kinetics equation,and the apparent rate constant decreases with the increase of the initial concentration.