Preparation And Properties Of Modified Bi₂WO₆and Zn₂GeO₄Ternary Metal Oxide Semiconductor Photocatalysts

With the development of global industry, the environmental pollution hasbecome a serious social problem. Thus, it is quite urgent to develop a simple andhigh-effective method to solve these environmental problems what we are facing. Inthe past few years, due to their great potential in environmental purification,semiconductor photocatalysts have been received the researchers’ extensive attention.Although some exciting achievements have been obtained in the practical applicationbased on the traditional photocatalysts, a few shortages are existed, such as lowefficiency for light absorption, high recombination between photo-induced electronsand holes, difficult recycle and so on. Therefore, it is extremely necessary tosynthesize the new-type and high-efficiency photocatalysts for avoiding thedisadvantages mentioned above. This dissertation mainly focuses on solvothermalsynthesis and photocatalytic properties of the modified Bi2WO6and Zn2GeO4photocatalysts. It contains three parts as following:1. Using urea as nitrogen source, Bi2WO6photocatalysts with different N dopingcontent were prepared via hydrothermal method. The analysis results indicated thatthe morphology of obtained Bi2WO6products was microspheres that composed ofnanosheets. Photocatalytic degradation of RhB in aqueous solution was investigated.The results showed the0.5%N-doped Bi2WO6exhibited the highest photocatalyticperformance. This was attributed to high specific surface area and extensive lightabsorption.2. Both doping and deposition using noble metal could improve catalyticproperties of photocatalysts. In this section, simultaneously Ag doping and depositionZn2GeO4were prepared by solvothermal method. The morphology and structure ofthe resultant products were verified by SEM, TEM, XRD and XPS. The resultsshowed the existence of Ag+and Ag in the resultant product (Ag-Zn2GeO4).Photocatalytic experiments on removal of RhB and colorless phenol in aqueoussolution were carried out with assisted by light irradiation. The results showed that photocatalytic activity of0.1Ag-modified Zn2GeO4was higher than that of the otherAg-modified Zn2GeO4. This was ascribed that the moderate AgNO3made a suitableratio of doped Ag to deposited Ag, resulting the best photocatalytic property.3. Zn2GeO4/ACFs composites were prepared by indirect growth of Zn2GeO4nanorods on carbon fibers. The morphology and structure of Zn2GeO4/ACFs productswere characterized. Density functional theory has been employed to investigate thesurface energies of main Zn2GeO4facet and the interaction energies between mainZn2GeO4facet and CFs. The possible growth mechanism was provided according tothe calculation results. The obtained products exhibited higher photocatalytic activityfor oxidation of p-aminotoluene to p-nitrotoluene.