Detecting the Photoactivity of Anatase TiO2(001)-(1 x 4) Surface by Formaldehyde
Detecting the Photoactivity of Anatase TiO2(001)-(1 x 4) Surface by Formaldehyde
复制标题
用甲醛检测锐钛矿型 TiO2(001)-(1 x 4) 表面的光活性
DOI：
10.1021/acs.jpcc.7b04530
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发表时间：
2017
影响因子：
3.7
通讯作者：
Wang Bing
中科院分区：
文献类型：
--
作者：
Luo Bin;Tang Haoqi;Cheng Zhengwang;Ji Yuanyuan;Cui Xuefeng;Shi Yongliang;Wang Bing
我们报告了我们的研究，使用 CH2O 作为探针，使用程序升温解吸来检测还原锐钛矿 TiO2(001)-(1 × 4) 表面的活性和光活性。我们获得了 CH2O 在表面上的吸附能为 0.55 eV，并发现还原表面中的缺陷位点是热驱动反应产生 C2H4 的唯一活性位点。我们还确定了锐钛矿型 TiO2(001)-(1 × 4) 表面上 CH2O 光分解的途径，其中 C−H 键断裂形成 HCOO− 中间体应该是反应中的关键步骤。紫外光照射后，HCOO–在高温下解离产生CO和H2O。伴随着 H2O 的解吸，我们观察到 C2H4 的产量高于未辐照样品。我们通过将（1×4）脊结构的暂时变化归因于水解吸来解释我们的实验结果，即最初富氧的五重配位Ti原子变为四重配位Ti原子。因此，四重配位的 Ti 位点充当了 CH2O 偶联反应生成 C2H4 的高活性位点。我们的研究结果为锐钛矿型 TiO2(001)-(1 × 4) 表面上 CH2O 的热催化和光催化反应提供了深刻的理解。
We report our investigation using temperature-programmed desorption to detect the activity and the photoactivity of the reduced anatase TiO2(001)-(1 × 4) surface by using CH2O as a probe. We obtain the adsorption energy of 0.55 eV for CH2O on the surface and find that the defect sites in the reduced surface are the only active sites for thermally driven reaction to produce C2H4. We also identify the pathways for photodecomposition of CH2O on the anatase TiO2(001)-(1 × 4) surface, where the C−H bond breaking to form the intermediates of HCOO− should be a key step in the reactions. After the ultraviolet light irradiation, the dissociation of HCOO– produces CO and H2O at elevated temperatures. Accompanied by desorption of H2O, we observe higher production of C2H4than that in the non-irradiated sample. We interpret our experimental results by attributing the temporary change of the (1 × 4) ridge structure to water desorption, that is, the initially oxygen-rich five-fold coordinated Ti atoms change to four-fold coordinated Ti atoms. The four-fold coordinated Ti sites thus act as the highly active sites for the coupling reaction of CH2O to produce C2H4. Our findings here provide insightful understanding for the thermal and photocatalytic reactions of CH2O on the anatase TiO2(001)-(1 × 4) surface.