Double-heterojunction structure of SbxSn1-xO2/TiO2/CdSe for efficient decomposition of gaseous 2-propanol under visible-light irradiation
Double-heterojunction structure of SbxSn1-xO2/TiO2/CdSe for efficient decomposition of gaseous 2-propanol under visible-light irradiation
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DOI：
10.1039/c1ra00551k
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发表时间：
2012
期刊：
影响因子：
3.9
通讯作者：
Sher Bahadur Rawal;A. Chakraborty;Yong Joo Kim;H. Kim;W. Lee
中科院分区：
文献类型：
--
作者：
Sher Bahadur Rawal;A. Chakraborty;Yong Joo Kim;H. Kim;W. Lee
采用SnCl 4·5 H2O和SbCl 3共沉淀法制备了粒径为50 nm的高晶化掺锑氧化锡（ATO; SbxSn 1-xO 2，x = 0.1），并在1000 °C下进行热处理。所制备的ATO纳米粒子呈深蓝色，在可见光范围内具有明显的光吸收。采用溶胶-凝胶法在ATO纳米粒子表面包覆TiO 2，制备了ATO/TiO 2复合材料。在可见光照射下（λ ≥ 420 nm），ATO/TiO 2对气态异丙醇（IP）的光催化降解表现出显著的光催化活性，这可能是由于ATO的价电子能级低于TiO 2的价电子能级，ATO与TiO 2之间的空穴转移机制所致。在ATO/TiO 2表面负载CdSe量子点，制备了ATO/TiO 2/CdSe双异质结结构，显著提高了可见光催化效率。事实上，ATO/TiO 2/CdSe在从IP释放CO2中的催化活性是ATO/TiO 2的1.3倍，是典型的N掺杂TiO 2的2倍。ATO/TiO 2/CdSe的高效率似乎是由于这些半导体之间独特的能带匹配。在可见光照射下，ATO和CdSe的敏化不仅在TiO 2的VB和CB中产生空穴，而且还产生电子。
Highly crystallized antimony-doped tin oxide (ATO; SbxSn1-xO2, x = 0.1) of ∼50 nm size was prepared by co-precipitation of SnCl4·5H2O and SbCl3, followed by heat-treatment at 1000 °C. The prepared ATO nanoparticles of deep blue color revealed a profound light-absorption in the visible range. ATO/TiO2 composites were prepared by covering the surface of ATO nanoparticles with TiO2 using the sol–gel method. Under visible-light irradiation (λ ≥ 420 nm), the prepared ATO/TiO2 showed a notable photocatalytic efficiency in decomposing gaseous 2-propanol (IP), which seemed to be caused by the hole-transfer mechanism between the valence bands (VB) of ATO and TiO2, since the ATO's VB level is located lower than that of TiO2. Subsequently, a double-heterojunction ATO/TiO2/CdSe structure was prepared by loading CdSe quantum dots (QDs) onto the surface of the ATO/TiO2, which dramatically enhanced the visible-light photocatalytic efficiency. In fact, the catalytic activity of ATO/TiO2/CdSe in evolving CO2 from IP, was ∼3 times that of ATO/TiO2 and twice that of typical N-doped TiO2. The unexpectedly high efficiency of ATO/TiO2/CdSe seemingly is due to the unique band matching among these semiconductors. With sensitization of ATO and CdSe, not only the holes but also the electrons are generated in the VB and CB, respectively, of TiO2 under visible-light irradiation.