Preparation And Performance Study Of BiOCl-based Visible Light Composite Photocatalyst

In recent decades,the most serious water pollution is industrial waste water,but conventional water treatment systems are difficult to eliminate the persistent organic pollutants.Semiconductor photocatalysis is considered to be a highly efficient,environmentally friendly technology,its potential in solar energy conversion has attracted widespread attention.However,the traditional light catalyst,such as Ti O₂ has a wide band gap and can only response under ultraviolet light,which greatly limiting the practical application of photocatalysis.Therefore,need a new photocatalyst solve these problems.In recent years,the Bi based semiconductor photocatalysts such as Bi OCl because its[Bi₂O₂]²⁺and the chlorine atom unique double layer structure and potential of photocatalytic degradation ability,caused the widespread attention,but the band gap is wide,so in order to improve the biological activity of a single component,developing a variety of biological composite materials.In this paper,Bi based semiconductors and photosensitive materials are combined to form heterojunctions to promote the separation of photogenerated electron-hole pairs.And metal nanoparticles in the composite are reduced to form plasmon resonance,which synergistic effect can greatly improve the visible light absorption capacity.The photocatalytic performance of the composite photocatalyst and the photodegradation efficiency of several pollutants were analyzed,and the photocatalytic mechanism have also been discussed.The thesis focuses on the following contents:?1?The Bi OCl microsphere was synthesized via the hydrothermal synthesis method.And then Bi-Bi OCl was synthesized by chemical reduction,forming the surface plasmon resonance,then through a simple physical mixing,Bi-Bi OCl/Ag Cl composite microspheres heterojunction were synthesized.The degradation rate of BPA,2,6-dichlorophenol and 2,4,5-trichlorophenol photodegradation efficiency were 99%,96%and 99%,respectively.Moreover,the hydrogen production efficiency was 198.2?mol h^-1 g^-1 and 5 times of the original Bi OCl(45.6?mol h^-1 g^-1).According to a series of performance tests suggest the possible photocatalytic activity mechanism,which was due to the two substances form heterojunction close contact,heterojunction effect and reduction of the Bi formed Z-scheme structure,prolonged the life of electronic,the formation of the SPR effect to speed up the separation of the pairs.?2?The Bi₃O₄Cl nanosheets were successfully synthesized by one-step hydrothermal method and calcining method.Through the simple physical mixing composite Ag Cl photosensitive materials.By using the method of solid state reduction Bi,Ag nanoparticles come to form the plasma resonance at the same time,the new nanomaterials Bi-Bi₃O₄Cl/Ag-Ag Cl ultrathin nanosheets were synthesized.It showed the photocatalyst of ceftriatone sodium TOC removal rate was 98.9%,the reduction of the Cr?VI?reduction efficiency was 98.3%.Moreover,it had good thermal performance,and its mechanism was through a series of optical performance study identified,with photosensitive material compound formed heterojunction effect,shortened the band gap,and then restored the Bi,Ag particles,which created double plasma resonance can improve the photocatalytic performance.