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1、2015年l1月化學(xué)研究633第26卷第6期CHEMICALRESEARCHhttp://hxya.cbpt.cnki.net介孔AgBr/TiO2一SiO2光催化劑的制備及其可見光催化活性徐晶晶,劉建軍,左勝利,于迎春,李保山(北京化工大學(xué)理學(xué)院,北京100029)摘要:通過沉積法將光活性AgBr半導(dǎo)體負載到介孔TiO一SiO2載體上合成了新型的AgBr/TiO~SiO。復(fù)合光催化劑.采用x射線衍射儀、高分辨透射電鏡、紫外一可見吸收光譜儀等分析了AgBr/TiO一SiO復(fù)合光催化劑的結(jié)構(gòu)和光譜性質(zhì);并采用BET法測定了樣品的比表面積和孑L分
2、布.結(jié)果表明,介孔1rjO。一SiO載體的比表面積為135.51TI/g,平均孔徑約為3.8I'lrft,AgBr的負載可以有效地將AgBr/TiO。一SiO復(fù)合光催化劑的吸收光譜從紫外光區(qū)擴展到可見光區(qū),且AgBr和TiO形成了異質(zhì)結(jié)結(jié)構(gòu),強化了AgBr與介孔TiO一SiO載體的協(xié)同作用.以羅丹明B作為探針分子,評價了AgBr負載量對復(fù)合光催化劑可見光催化活性的影響.結(jié)果發(fā)現(xiàn),當AgBr:TiOz—O.1,O.2,o.3和o.4(物質(zhì)的量之比,下同)時,復(fù)合光催化劑的光催化反應(yīng)速率常數(shù)分別為o.0085、O.0286、O.0246和0.01
3、93rain一,活性先增加后減小,當AgBr;TiO2一O.2時,復(fù)合光催化劑表現(xiàn)出最高的光催化活性,并且在5次循環(huán)測試中均表現(xiàn)出較高的光催化活性.關(guān)鍵詞:介孔Ti0一siO;AgBr;可見光;光催化劑;羅丹明B中圖分類號:O643.3文獻標志碼:A文章編號:1008—1011(g015)06—0633—05PreparationofmesoporousAgBr/TiO2一SiO2compositeswithenhancedph0t0catalyticactivityundervisiblelightXUJingjing,LIUJianjun
4、,ZUOShengli,YUYingchun,LIBaoshan(CollegeofScience,BeijingUniversityofChemicalTechnology,Beijing,100029,China)Abstract:NovelAgBr/TiO2-SiO2compositesweresynthesizedbyintroducingphotoactiveAg—BrcomponentontothemesoporousTiO2-SiO2supports.MorphologiesandstructuresofAgBr/TiO2一Si
5、O2compositeswerecharacterizedbyX—raydiffraction,nitrogenadsorption—desorptionisotherm,highresolutiontransmissionelectronmicroscopyandUV—visdiffusereflectancespectra.TheresultsshowthatthemesoporousTiO2-SiO2supportspossesslargespecificsur—faceareasof135.5m/gandaverageporediam
6、eterofabout3.8nm.AgBr—loadingcaneffec—tivelyextendthespectralresponsefromUVtovisibleregionforAgBr/TiO2一SiO2composite.TheformationofAgBr-Ti02heterojunctionenhancesthephotocata1yticactivity.Thesynerget—iceffectbetweenAgBrandTiO2-SiO2hasbeeninvestigated.Thephotocatalyticactivi
7、tywasexaminedbythedegradationforRhBundervisiblelightirradiation.TheeffectsofloadingamountsofAgBronthephotocatalyticactivitiesofAgBr/TiO2一SiO2compositewerestudied.ItisfoundthatthereactionrateconstantsfortheAgBr/TiO2-SiO2compositesareO.0085,O.0286,O.0246and0.0193min一,respecti
8、vely,whilechangingthemolarratiosofAgBr:TiO2一O.1,O.2,O.3andO.4wherethecompositephot