Synthesis,Modification And Properties Of Bismuth Oxide Formate Photocatalyst

Photocatalysis has received more and more attention due to its potential applications in solar energy conversion,environmental remedy and organic synthesis.However,there are also many bottlenecks of photocatalyst in the practical application,like the complex preparation methods of photocatalyst,high cost,low output,short life of photocarriers and so on.It is a key step to simplify the synthesis of semiconductor photocatalysts and realize the effective separation of photoelectron and hole pairs.Bismuth oxide formate（HCOOBiO）was firstly prepared from solid-state chemical reaction by a facile room-temperature grinding method.In addition,the halogen doping modification was carried out to improve the photocatalytic performance,which has far-reaching significance for theoretical research and practical application.The research was summarized as follows:（1）Using sodium formate（HCOONa）and bismuth nitrate pentahydrate（Bi（NO₃）₃?5H₂O）as raw materials,the nanosheet HCOOBiO was firstly prepared from solid-state chemical reaction by a facile room-temperature grinding method..The phase,morphology and structure of the samples were characterized by XRD,SEM,DRS and other methods.The results showed that when the molar ratio of HCOONa to Bi is 5,high purity and good crystallinity of HCOOBiO can be obtained.（2）In order to increase the visible light response activity of HCOOBiO,the solid solutions of BiOR-Bi OBr and BiOR-Bi OI（marked as BiORX-n;R=HCOO;X=Br,I;n is molar ratio of X/Bi）were prepared by adding potassium iodide（KI）or potassium bromide（KBr）in one pot and grinding for a period of time.By changing the value of the n to adjust the band gap and band position of the solid solutions,the product with the best visible light absorption ability and photooxidation ability can be obtained.Among them,BiORI-0.4 and BiORBr-0.6 have the best photocatalytic performance.It is confirmed that BiORI-0.4 and BiORBr-0.6 have higher carrier separation efficiency by transient photocurrent and EIS tests.（3）HCOOBiO was further modified by co-doping method.On the basis of grinding to prepare HCOOBiO,KI and KBr were added successively,and BiOR-Bi OI-Bi OBr solid solutions were obtained by grinding（denoted as BiOR_xI_yBr_z,where x is the molar ratio of R/Bi,y is the molar ratio of I/Bi,z is the molar ratio of Br/Bi）,The results showed that when y=z=0.3 the photocatalytic activity of BiOR_0.4I_0.3Br_0.3 solid solution is better than that of BiORI-0.4 and BiORBr-0.6,which is possiblely due to the more suitable band gap,band position and specific surface of BiOR_0.4I_0.3Br_0.3.