Ti(IV) nanoclusters as a promoter on semiconductor photocatalysts for the oxidation of organic compounds
Ti(IV) nanoclusters as a promoter on semiconductor photocatalysts for the oxidation of organic compounds
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DOI：
10.1039/c5ta08340k
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发表时间：
2016-01
影响因子：
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通讯作者：
Ryota Inde;Min Liu;D. Atarashi;E. Sakai;M. Miyauchi
中科院分区：
文献类型：
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作者：
Ryota Inde;Min Liu;D. Atarashi;E. Sakai;M. Miyauchi
半导体的表面修饰是开发可见光敏感光催化剂的潜在方法。在这里，我们报告接枝到金属氧化物光催化剂上的无定形 Ti(IV) 纳米团簇可作为有机污染物（包括乙醛和 2-丙醇）氧化的有效促进剂。通过使用简单的浸渍方法，Ti(IV) 纳米簇可以轻松地接枝到二氧化钛 (TiO2) 和三氧化钨 (WO3) 等金属氧化物上。 Ti(IV)纳米簇接枝TiO2在紫外光照射下的光催化活性远高于裸TiO2，尽管这两种材料的表面积和光子吸收相同。光催化活性的提高归因于Ti(IV)纳米团簇的空穴捕获，形成独特的电子结构，从而实现有效的电荷分离。开尔文探针力显微镜分析表明，Ti(IV)纳米团簇的最高占据分子轨道(HOMO)比块体金红石TiO2的价带具有更大的负电势，这允许空穴从块体TiO2转移到Ti(IV)纳米团簇。 Ti(IV) 纳米团簇的接枝也被证明可以提高 WO3 的光催化活性。 WO3 还需要还原反应促进剂，例如 Cu(II) 纳米团簇，因为其导带 (CB) 能量较低。 Ti(IV) 和 Cu(II) 纳米团簇接枝到 WO3 上产生了迄今为止报道的可见光照射下气态 2-丙醇分解的最高反应速率。
The surface modification of semiconductors is a potential approach for the development of visible-light-sensitive photocatalysts. Here, we report that amorphous Ti(IV) nanoclusters grafted onto metal oxide photocatalysts function as efficient promoters for the oxidation of organic contaminants, including acetaldehyde and 2-propanol. Ti(IV) nanoclusters were facilely grafted onto metal oxides like titanium dioxide (TiO2) and tungsten trioxide (WO3) by using a simple impregnation method. The photocatalytic activity of Ti(IV) nanocluster-grafted TiO2 under UV-light irradiation was much higher than that of bare TiO2, even though the surface area and photon absorption of these two materials were identical. The improved photocatalytic activity was attributable to hole trapping by the Ti(IV) nanoclusters, which form a unique electronic structure, resulting in efficient charge separation. Kelvin probe force microscopy analysis revealed that the highest occupied molecular orbital (HOMO) of the Ti(IV) nanoclusters has a more negative potential than the valence band of bulk rutile TiO2, which allows hole transfer from bulk TiO2 to the Ti(IV) nanoclusters. The grafting of Ti(IV) nanoclusters was also shown to increase the photocatalytic activity of WO3. WO3 also requires reduction reaction promoters, such as Cu(II) nanoclusters, because of the low energy of its conduction band (CB). The grafting of both Ti(IV) and Cu(II) nanoclusters onto WO3 resulted in the highest reaction rate reported to date for the decomposition of gaseous 2-propanol under visible-light irradiation.