Study On Preparation And Photocatalytic Activity Of A Novel Photocatalyst Bi₂WO₆

This paper introduced a novel photocatalyst,bismuth tungstate(Bi2WO6).Due to its characteristics,including large response range to light and excellent photocatalytic activity,it attracted more and more attention.This study introduced photocatalytic technology and its current status of research and development,and made a brief overview of its application field.In this paper,the preparation method and catalytic activity of bismuth tungstate were elaborated,and the catalytic reaction mechanism was discussed.In this paper,novel photocatalytic material,Bi2WO6,was prepared using sol-gel method.Photocatalysts prepared using this method had several advantages,including uniform particle size,good surface area and high photocatalytic activity.The preparation process was as follows:Bi(?)? W(W)? oxide ? polyethylene glycol ? gel ? heat treatment(calcination)?sample treatment(washing,drying).Then the photocatalytic activity was studied using reducing CO2 reaction,and characterized by XRD,SEM,GC-MS,TG-DTG,UV-Vis DRS and GC-MS.The results showed that Bi2WO6 photocatalyst prepared with precursor solution pH=1 and gel calcining temperature T=450? during the sol-gel process represented better photocatalytic activity in the photocatalytic reduction process of CO2.In the reduction of CO2,when the concentration of NaOH and Na2SO3 in solution was 0.10mol/L,the amount of catalyst was 1.5g/L,the flow rate of CO2 was 150mL/min,the irradiation time was t=7h,and the reaction temperature was about 50?,the catalytic efficiency was the highest and the yield of methanol,the principal product,was up to about 184.7?mol-gcat-1.The mechanism of CO2 photocatalytic reduction was discussed based on experimental data,and the brief reaction process was as follows:CO2 ? HCOOH? HCHO ? CH3OH.The reaction mechanism of methanol during the process was discussed in detail,and mechanisms of other products existed in the reaction solution were also speculated.The influence of "light-surface-heat" synergistic effect on photocatalytic reduction of CO2 was analyzed based on experimental results and it was found that the synergistic effect,supported by appropriate light energy and thermal energy on catalyst surface,could improve the utilization of light energy and the efficiency of photons.