Photocatalytic reduction of CO2 with H2O to CH4 on Cu(I) supported TiO2 nanosheets with defective {001} facets.
Photocatalytic reduction of CO2 with H2O to CH4 on Cu(I) supported TiO2 nanosheets with defective {001} facets.
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DOI：
10.1039/c5cp00647c
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发表时间：
2015-04
期刊：
影响因子：
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通讯作者：
Shuying Zhu;Shijing Liang;Y. Tong;X. An;Jinlin Long;Xianzhi Fu;Xuxu Wang
中科院分区：
文献类型：
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作者：
Shuying Zhu;Shijing Liang;Y. Tong;X. An;Jinlin Long;Xianzhi Fu;Xuxu Wang
通过水热处理和光沉积制备了负载在具有显性暴露{001}面的TiO2纳米片上的高度分散的Cu2O簇。对制备的样品的物理化学性质进行了仔细的表征。利用x射线衍射、透射电子显微镜、紫外-可见漫反射光谱、EPR光谱和原位co -吸附FTIR光谱分别表征了Cu2O团簇的沉积位置和化学状态。结果表明，原位Cu沉积导致TiO2纳米片表面原位形成丰富的氧空位（Vo）。有趣的是，Vo和Cu2O团簇的共存可以有效地促进CO2还原的光活性。表面Vo对CO2的还原有重要作用。同时，沉积的Cu(I)也作为CH4生成的活性位点，保护CH4不被生成的氧化物质降解。对于CO2光还原为CH4，发现Cu2O的含量水平对活性有显著影响。Cu-TiO2-1.0表现出最高的光催化活性，比母体TiO2的光催化活性高30倍以上。高CO2吸附能力、高电子迁移率和高浓度的Vo可能是光催化活性增强的主要原因。然而，样品的表面积对活性的影响可以忽略不计。所有这些证据都是通过二氧化碳吸附，电化学，原位FTIR光谱，原位ERP技术等获得的。用原位傅立叶变换红外光谱对反应中间体进行了检测。最后，根据实验结果提出了一种可能的机理。希望我们的工作能够提供一种最有效的策略来实现二氧化碳太阳能转换的光功能材料的先进性能。
Highly dispersed Cu2O clusters loaded on TiO2 nanosheets with dominant exposed {001} facets are prepared by a hydrothermal treatment followed by photodeposition. The physicochemical properties of the as-prepared samples are characterized carefully. The deposition position and chemical state of the Cu2O clusters are characterized by X-ray diffraction, transmission electron microscopy, UV-vis diffuse reflectance spectroscopy, EPR spectroscopy, and in situ CO-adsorbed FTIR spectroscopy, respectively. The results show that in situ Cu deposition leads to in situ formation of abundant oxygen vacancies (Vo) on the surface of the TiO2 nanosheets. Interestingly, the co-existence of Vo and Cu2O clusters could promote the photoactivity of CO2 reduction efficiently. The surface Vo play a significant role in the reduction of CO2. Meanwhile, the deposited Cu(I) species serve also as active sites for the formation of CH4, and then protect CH4 from degradation by generated oxidation species. For the photoreduction of CO2 to CH4, it is found that the content level of Cu2O has a significant influence on the activity. Cu-TiO2-1.0 shows the highest photocatalytic activity, which is over 30 times higher than that of the parent TiO2. This great enhancement of photocatalytic activity may be contributed by high CO2 adsorption capacity, high electron mobility, and high concentration of Vo. However, the effect of the surface area of the samples on the activity is negligible. All of this evidence is obtained by CO2-sorption, electrochemistry, in situ FTIR spectroscopy, in situ ERP techniques, etc. The reaction intermediates are detected by in situ FTIR spectroscopy. Finally, a probable mechanism is proposed based on the experimental results. It is hoped that our work could render one of the most effective strategies to achieve advanced properties over photofunctional materials for solar energy conversion of CO2.