物理化学学报
物理化學學報
물이화학학보
ACTA PHYSICO-CHIMICA SINICA
2013年
6期
1305-1312
,共8页
张鹏%赵路松%姚江宏%曹亚安
張鵬%趙路鬆%姚江宏%曹亞安
장붕%조로송%요강굉%조아안
Sn4+离子掺杂TiO2%Sn4+离子浓度%瞬态光电压%表面光电压谱%光生电子的寿命
Sn4+離子摻雜TiO2%Sn4+離子濃度%瞬態光電壓%錶麵光電壓譜%光生電子的壽命
Sn4+리자참잡TiO2%Sn4+리자농도%순태광전압%표면광전압보%광생전자적수명
Sn4+-doped TiO2%Content of Sn4+ ions%Transient photovoltage%Surface photovoltage spectroscopy%Life time of photo-generated electrons
采用溶胶-凝胶法制备出纯TiO2和不同浓度Sn4+离子掺杂的TiO2光催化剂(TiO2-Snx%, x%代表Sn4+离子掺杂的 TiO2样品中 Sn4+离子摩尔分数).利用 X 射线衍射(XRD)、X 射线光电子能谱(XPS)和表面光电压谱(SPS)确定了TiO2-Snx%催化剂的晶相结构和能带结构,结果表明:当Sn4+离子浓度较低时, Sn4+离子进入TiO2晶格,取代并占据Ti4+离子的位置,形成取代式掺杂结构(Ti1-xSnxO2),其掺杂能级在导带下0.38 eV处;当Sn4+离子浓度较高时,掺入的Sn4+离子在TiO2表面生成金红石SnO2,形成TiO2和SnO2复合结构(TiO2/SnO2), SnO2的导带位于TiO2导带下0.33 eV处.利用瞬态光电压谱和荧光光谱研究了TiO2-Snx%催化剂光生载流子的分离和复合的动力学过程,结果表明, Sn4+离子掺杂能级和表面SnO2能带存在促进光生载流子的分离,有效地抑制了光生电子与空穴的复合;然而, Sn4+离子掺杂能级能更有效地增加光生电子的分离寿命,提高了光生载流子的分离效率,从而揭示了TiO2-Snx%催化剂的光催化机理.
採用溶膠-凝膠法製備齣純TiO2和不同濃度Sn4+離子摻雜的TiO2光催化劑(TiO2-Snx%, x%代錶Sn4+離子摻雜的 TiO2樣品中 Sn4+離子摩爾分數).利用 X 射線衍射(XRD)、X 射線光電子能譜(XPS)和錶麵光電壓譜(SPS)確定瞭TiO2-Snx%催化劑的晶相結構和能帶結構,結果錶明:噹Sn4+離子濃度較低時, Sn4+離子進入TiO2晶格,取代併佔據Ti4+離子的位置,形成取代式摻雜結構(Ti1-xSnxO2),其摻雜能級在導帶下0.38 eV處;噹Sn4+離子濃度較高時,摻入的Sn4+離子在TiO2錶麵生成金紅石SnO2,形成TiO2和SnO2複閤結構(TiO2/SnO2), SnO2的導帶位于TiO2導帶下0.33 eV處.利用瞬態光電壓譜和熒光光譜研究瞭TiO2-Snx%催化劑光生載流子的分離和複閤的動力學過程,結果錶明, Sn4+離子摻雜能級和錶麵SnO2能帶存在促進光生載流子的分離,有效地抑製瞭光生電子與空穴的複閤;然而, Sn4+離子摻雜能級能更有效地增加光生電子的分離壽命,提高瞭光生載流子的分離效率,從而揭示瞭TiO2-Snx%催化劑的光催化機理.
채용용효-응효법제비출순TiO2화불동농도Sn4+리자참잡적TiO2광최화제(TiO2-Snx%, x%대표Sn4+리자참잡적 TiO2양품중 Sn4+리자마이분수).이용 X 사선연사(XRD)、X 사선광전자능보(XPS)화표면광전압보(SPS)학정료TiO2-Snx%최화제적정상결구화능대결구,결과표명:당Sn4+리자농도교저시, Sn4+리자진입TiO2정격,취대병점거Ti4+리자적위치,형성취대식참잡결구(Ti1-xSnxO2),기참잡능급재도대하0.38 eV처;당Sn4+리자농도교고시,참입적Sn4+리자재TiO2표면생성금홍석SnO2,형성TiO2화SnO2복합결구(TiO2/SnO2), SnO2적도대위우TiO2도대하0.33 eV처.이용순태광전압보화형광광보연구료TiO2-Snx%최화제광생재류자적분리화복합적동역학과정,결과표명, Sn4+리자참잡능급화표면SnO2능대존재촉진광생재류자적분리,유효지억제료광생전자여공혈적복합;연이, Sn4+리자참잡능급능경유효지증가광생전자적분리수명,제고료광생재류자적분리효솔,종이게시료TiO2-Snx%최화제적광최화궤리.
@@@@Pure TiO2 and Sn4+ doped TiO2 (TiO2-Snx%) photocatalysts were prepared by a sol-gel method, where x% represents the nominal molar fraction of Sn4+ ions in the TiO2 structure. The crystal structure and energy band structure of the resultant catalysts were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and surface photovoltage spectroscopy (SPS). The results show that for a low content of Sn4+ ions, the Sn4+ ions are doped into the TiO2 lattice and replace lattice Ti4+ ions in a substitute mode (Ti1-xSnxO2). The energy levels of these Sn4+ ions are located 0.38 eV below the conduction band. Moreover, the rutile SnO2 crystal structure evolves with increasing content of Sn4 + ions, i.e., a TiO2/SnO2 structure is formed. The conduction band of SnO2 is located 0.33 eV lower than that of TiO2. The separation and recombination mechanism of the photo-generated carriers was characterized by photoluminescence and transient photovoltage techniques. The results showed that the formation of the energy levels of Sn4+ ions and the conduction band of rutile SnO2 can enhance the separation of the photo-generated carriers, and suppress the recombination of photo-generated carriers. However, the energy levels of Sn4 + can lead to a much longer life time and higher separation efficiency of the photo-generated carriers. For different content of Sn4 + in Sn4 + ion doped TiO2 (TiO2-Snx%), the abovementioned aspects improve the photocatalytic activity.
