Preparation,Characterization And Visible Photocatalytic Activity Of Ag₃PO₄Photocatalyst

With the rapid development of industrialization, the environmenhtal pollution and energy crisis have attracted much more attention. The purification materials based on nano-TiO2become very popular for its low price, chemical stability, nontoxic, energy saving etc. But it is limited by its poor absorption of visible light because TiO2has a large band gap. So it is significant to find a photocatalyst with high efficience under visible light. It has drawn much attention since Ye reported that Ag3PO4is a high efficient photocatalyst with AgNO3as electron caputure agent under visible light on Nature Materials. The photocatalytic activity and stability without electron capture agent need further study. In this wok, the photocatalytic activity and stability of Ag3PO4photocatalyst under visible light were studied. The main contents and conclusions are as follows:Ag3PO4with different microstructures were prepared by a facile ion-exchange rout. Both the two can absorb visible light.The as-prepared composite photocatalysts showed apronounced photocatalytic activity upon decomposition of both ionic and cationic dyestuffs, as well as p-chlorophenol (PC) in aqueous solution under visible light (wavelength≥400nm), while nearly no degradation reaction with benzene and acetone. And cationic dyes (crystal violet and methylene blue) have a higher degradation rate than anionic dyes (methyl orange and orange-G) for the same catalyst. Cubic Ag3PO4has a higher degradation rate than spherical Ag3PO4for the same organic dye solution. In addition to the TOC of crystal violet dye solusion after reaction reduced, methylene blue and methyl orange, orange yellow G and chloride phenol got no obvious change. Thus, the Ag3PO4only involved in a decolorzing reaction process. The organics can not be oxidated into CO2and H2O by AgsPO4. A further explanation of inherent photocatalytic capability was interpreted by total organic carbon content and detection of hydroxyl radicals methods. There were no hydroxyl radicals (·OH) created in system under visible light. The organic molecules were degradated by holes but can not be oxidated into CO2and H2O for the holes got a low potential. The surface of photocatalyst was restred to metal silver after8circles according to the change of colour from olive to dark. The poor stability of Ag3PO4was improved by adding H2O2which act as electron caputure agent in order to protect photocatalyst.