中国环境科学
中國環境科學
중국배경과학
China Environmental Science
2015年
11期
3317-3324
,共8页
光催化%钒酸银%改性%二氧化钛
光催化%釩痠銀%改性%二氧化鈦
광최화%범산은%개성%이양화태
photocatalysis%silver vanadate%modification%titania
通过水热法将钒酸银掺杂负载到二氧化钛上,制备了一种新型改性二氧化钛复合光催化剂.利用扫描电镜、透射电镜、X射线衍射、X射线光电子能谱和紫外-可见光漫反射技术对催化剂进行了表征,以亚甲基蓝为目标降解物,考察了该催化剂在可见光下的光催化活性、稳定性等,探讨分析了反应机理.结果表明,可见光下该催化剂降解亚甲基蓝的反应过程符合一级反应动力学,其降解速率常数为0.009min-1,是二氧化钛P25的3倍,且3次回收利用后降解率仅下降4.8%,仍具有较高活性.钒酸银与二氧化钛形成耦合异质结,在可见光照射下,光生电子由钒酸银导带传到二氧化钛导带上,空穴则聚集在钒酸银价带上,产生的h+、·OH等是降解亚甲基蓝的主要物质,电子与受体的结合是反应的限速步骤.
通過水熱法將釩痠銀摻雜負載到二氧化鈦上,製備瞭一種新型改性二氧化鈦複閤光催化劑.利用掃描電鏡、透射電鏡、X射線衍射、X射線光電子能譜和紫外-可見光漫反射技術對催化劑進行瞭錶徵,以亞甲基藍為目標降解物,攷察瞭該催化劑在可見光下的光催化活性、穩定性等,探討分析瞭反應機理.結果錶明,可見光下該催化劑降解亞甲基藍的反應過程符閤一級反應動力學,其降解速率常數為0.009min-1,是二氧化鈦P25的3倍,且3次迴收利用後降解率僅下降4.8%,仍具有較高活性.釩痠銀與二氧化鈦形成耦閤異質結,在可見光照射下,光生電子由釩痠銀導帶傳到二氧化鈦導帶上,空穴則聚集在釩痠銀價帶上,產生的h+、·OH等是降解亞甲基藍的主要物質,電子與受體的結閤是反應的限速步驟.
통과수열법장범산은참잡부재도이양화태상,제비료일충신형개성이양화태복합광최화제.이용소묘전경、투사전경、X사선연사、X사선광전자능보화자외-가견광만반사기술대최화제진행료표정,이아갑기람위목표강해물,고찰료해최화제재가견광하적광최화활성、은정성등,탐토분석료반응궤리.결과표명,가견광하해최화제강해아갑기람적반응과정부합일급반응동역학,기강해속솔상수위0.009min-1,시이양화태P25적3배,차3차회수이용후강해솔부하강4.8%,잉구유교고활성.범산은여이양화태형성우합이질결,재가견광조사하,광생전자유범산은도대전도이양화태도대상,공혈칙취집재범산은개대상,산생적h+、·OH등시강해아갑기람적주요물질,전자여수체적결합시반응적한속보취.
A novel silver vanadate modified titania photocatalyst was prepared by one-pot hydrothermal method in this paper. The product was characterized by scanning electron microscope, transmission electron microscope, X-ray diffraction, X-ray photoelectron spectroscopy and UV-vis diffuse reflectance spectroscopy analysis. Methelene blue(MB) was employed to investigate its photocatalytic activity and stability, and the mechanism of the degradation of MB was also discussed according to experimental results. The results demonstrated that the photocatalytic degradation of MB by silver vanadate modified titania was a first-order reaction, and the rate constant (0.009 min-1) was three times bigger than that of P25 under visible light irradiation. The enhancement of the photocatalytic activity might attribute to the formation of coupling heterojunction between silver vanadate and titanium, and the photo-generated electrons could spontaneously migrate from conduction band of silver vanadate to conduction band of titania while the hole left on the valence band of silver vanadate to generate hydroxyl radical. The oxidation of hole as well as hydroxyl radicals played a leading role in the action. The combination of electron and receptor was the limiting step. In addition, the hybrids showed strong stability and high activity in this study. The degradation rate decreased only 4.8% after repeated for three times.
